(reposted from SED)
I want to try soldering some aluminum plate (0.032”) onto each side
of
a brass cylinder. When trying to solder aluminum in the past I
failed. I think I heard that some Al alloys are easier to solder
than
others. I’ve got a choice (From McMaster-C) of 6061, 2024. 7075, and
1100. Any idea of which is better?

I was also planning on getting some aluminum flux and some Zn/tin
solder from McM-C. Other suggestions welcome.


Thanks


George H.

In article
,
George Herold wrote:

(reposted from SED)
I want to try soldering some aluminum plate (0.032²) onto each side
of
a brass cylinder. When trying to solder aluminum in the past I
failed. I think I heard that some Al alloys are easier to solder
than
others. I¹ve got a choice (From McMaster-C) of 6061, 2024. 7075, and
1100. Any idea of which is better?

I was also planning on getting some aluminum flux and some Zn/tin
solder from McM-C. Other suggestions welcome.

If the temperature coefficients of linear expansion of the brass and the
aluminum don't match to within something like 1%, the joint will surely
tear itself apart, no matter how well soldered the joint is.

Joe Gwinn

On Jun 29, 11:23*am, Joseph Gwinn wrote:
In article
,
*George Herold wrote:

(reposted from SED)
I want to try soldering some aluminum plate (0.032²) onto each side
of
a brass cylinder. *When trying to solder aluminum in the past I
failed. *I think I heard that some Al alloys are easier to solder
than
others. *I¹ve got a choice (From McMaster-C) of 6061, 2024. 7075, and
1100. * Any idea of which is better?

I was also planning on getting some aluminum flux and some Zn/tin
solder from McM-C. *Other suggestions welcome.

If the temperature coefficients of linear expansion of the brass and the
aluminum don't match to within something like 1%, the joint will surely
tear itself apart, no matter how well soldered the joint is.

Joe Gwinn

Hmm, OK thanks. I was thinking of trying a thin layer of epoxy too.
But soldering would be better.
The linear expansion coef. of brass and Al differ by ~ 4E-6/C
http://en.wikipedia.org/wiki/Thermal...ious_materials

So if soldering happens at 300C (?) then the thin aluminum plate has
to shrink by a part per thousand (or so). Maybe 2 mils for a 1.5 inch
diameter cylinder. I have no idea if a thin Al plate can accomidate
such strain. (I'll find out.)

Would a nice soft alloy like 1100 be best?

George H.

On Fri, 29 Jun 2012 11:23:17 -0400, Joseph Gwinn
wrote:

In article
,
George Herold wrote:

(reposted from SED)
I want to try soldering some aluminum plate (0.032²) onto each side
of
a brass cylinder. When trying to solder aluminum in the past I
failed. I think I heard that some Al alloys are easier to solder
than
others. I¹ve got a choice (From McMaster-C) of 6061, 2024. 7075, and
1100. Any idea of which is better?

I was also planning on getting some aluminum flux and some Zn/tin
solder from McM-C. Other suggestions welcome.

If the temperature coefficients of linear expansion of the brass and the
aluminum don't match to within something like 1%, the joint will surely
tear itself apart, no matter how well soldered the joint is.

Nonsense.

--
Ned Simmons

In article
,
George Herold wrote:

On Jun 29, 11:23*am, Joseph Gwinn wrote:
In article
,
*George Herold wrote:

(reposted from SED)
I want to try soldering some aluminum plate (0.032²) onto each side
of
a brass cylinder. *When trying to solder aluminum in the past I
failed. *I think I heard that some Al alloys are easier to solder
than
others. *I¹ve got a choice (From McMaster-C) of 6061, 2024. 7075, and
1100. * Any idea of which is better?

I was also planning on getting some aluminum flux and some Zn/tin
solder from McM-C. *Other suggestions welcome.

If the temperature coefficients of linear expansion of the brass and the
aluminum don't match to within something like 1%, the joint will surely
tear itself apart, no matter how well soldered the joint is.

Joe Gwinn

Hmm, OK thanks. I was thinking of trying a thin layer of epoxy too.
But soldering would be better.
The linear expansion coef. of brass and Al differ by ~ 4E-6/C
http://en.wikipedia.org/wiki/Thermal_expansion#Thermal_expansion_coefficients_f or_various_materials

So if soldering happens at 300C (?) then the thin aluminum plate has
to shrink by a part per thousand (or so). Maybe 2 mils for a 1.5 inch
diameter cylinder. I have no idea if a thin Al plate can accomidate
such strain. (I'll find out.)

Would a nice soft alloy like 1100 be best?

If it's thin enough that it will yield.

I have the impression that the area of the plate is large, and 1.5"
diameter is in the range. A few mils may not sound like much, but when
metals fight, the stresses are large, and solder is weak.

The issue is that below the solidus temperature (where the solder
becomes solid) as the two metals cool they shrink differentially,
putting shear stress on the joint. If the solder gives enough (which
depends on the max dimension between far points that are soldered), then
no problem. Unless we have temperature cycling, which will fatigue the
solder and break the joint.

Rigid epoxy will also fail. What can work is a silicon rubber adhesive,
so long as the adhesive layer is thick enough to accommodate the shear
strain without tearing.

War story: In the 1970s, I and a partner made lab instruments for
measuring how much drugged rats run around (yes, this is useful to
know). The instrument consisted of a big sheet steel base about 12"
wide by about 24" long by maybe 4" high, with a milky plexiglass cover
glued to the top. Light diffused through the plexiglass to light
receptors within the base. The problem was that the glue joint between
plexiglass cover and steel base was breaking, despite use of the best of
adhesives (a silicon rubber adhesive caulk), the covers were coming
loose, and customers were unhappy.

Plexiglass has something like five times the temperature coefficient of
aluminum, never mind steel, so normal variation in temperature in the
customer labs was enough to tear the joints apart, even in labs with
only a few degrees of diurnal variation. We measured the strength of
the joints - it was something like 50 or 100 pounds per inch in a lap
joint, and yet the joints broke within a year.

The solution was simple enough: Put 1/16" thick spacers in the joints
so there was always enough rubber that it didn't tear as temperature
variation caused the cover to get larger and smaller compared to the
steel base.


Anyway, is there any reason the aluminum sheet cannot be brass instead?

The other alternative is an interlayer having intermediate tempco, to
spread the strain out. For instance, stainless steel has a tempco
intermediate between aluminum and brass.


Joe Gwinn

On Jun 29, 1:43*pm, Joseph Gwinn wrote:
In article
,
*George Herold wrote:





On Jun 29, 11:23*am, Joseph Gwinn wrote:
In article
,
*George Herold wrote:

(reposted from SED)
I want to try soldering some aluminum plate (0.032²) onto each side
of
a brass cylinder. *When trying to solder aluminum in the past I
failed. *I think I heard that some Al alloys are easier to solder
than
others. *I¹ve got a choice (From McMaster-C) of 6061, 2024. 7075, and
1100. * Any idea of which is better?

I was also planning on getting some aluminum flux and some Zn/tin
solder from McM-C. *Other suggestions welcome.

If the temperature coefficients of linear expansion of the brass and the
aluminum don't match to within something like 1%, the joint will surely
tear itself apart, no matter how well soldered the joint is.

Joe Gwinn

Hmm, OK thanks. *I was thinking of trying a thin layer of epoxy too.
But soldering would be better.
The linear expansion coef. of brass and Al differ by ~ 4E-6/C
http://en.wikipedia.org/wiki/Thermal_expansion#Thermal_expansion_coef....

So if soldering happens at 300C (?) then the thin aluminum plate has
to shrink by a part per thousand (or so). *Maybe 2 mils for a 1.5 inch
diameter cylinder. *I have no idea if a thin Al plate can accomidate
such strain. *(I'll find out.)

Would a nice soft alloy like 1100 be best?

If it's thin enough that it will yield.

I have the impression that the area of the plate is large, and 1.5"
diameter is in the range. *A few mils may not sound like much, but when
metals fight, the stresses are large, and solder is weak.

The issue is that below the solidus temperature (where the solder
becomes solid) as the two metals cool they shrink differentially,
putting shear stress on the joint. *If the solder gives enough (which
depends on the max dimension between far points that are soldered), then
no problem. *Unless we have temperature cycling, which will fatigue the
solder and break the joint.

Rigid epoxy will also fail. *What can work is a silicon rubber adhesive,
so long as the adhesive layer is thick enough to accommodate the shear
strain without tearing.

Well I'll glue it at room temp and then use it at room temp, so maybe
not as much of a problem.


War story: *In the 1970s, I and a partner made lab instruments for
measuring how much drugged rats run around (yes, this is useful to
know). *The instrument consisted of a big sheet steel base about 12"
wide by about 24" long by maybe 4" high, with a milky plexiglass cover
glued to the top. *Light diffused through the plexiglass to light
receptors within the base. *The problem was that the glue joint between
plexiglass cover and steel base was breaking, despite use of the best of
adhesives (a silicon rubber adhesive caulk), the covers were coming
loose, and customers were unhappy.

Plexiglass has something like five times the temperature coefficient of
aluminum, never mind steel, so normal variation in temperature in the
customer labs was enough to tear the joints apart, even in labs with
only a few degrees of diurnal variation. *We measured the strength of
the joints - it was something like 50 or 100 pounds per inch in a lap
joint, and yet the joints broke within a year.

The solution was simple enough: *Put 1/16" thick spacers in the joints
so there was always enough rubber that it didn't tear as temperature
variation caused the cover to get larger and smaller compared to the
steel base.

Anyway, is there any reason the aluminum sheet cannot be brass instead?

Yeah I'm pretty much stuck with aluminum. (But I'm open to other
materials if there are any suggestions.) I just started these
acoustic experiments. I wanted to show impedance matching for
acoustics. (Like a 1/4 wavlength AR coating in optics.) I've got a
brass cylinder that's acting like an acoustic Fabry-Perot cavity.
There are transducers on each side (one source and the other
detector). The transducers have an acoustic impedance of about 3 (in
some units.) The brass has an impedcance of about 40 in the same
units. So to make an AR coating I need 1/4 wavelength of a material
with a mean value between the two. (sqrt(3*40)) ~11.
Aluminum has an impedance of ~17 which seems to be close enough. I
should also try some glass which has about the right impedance.
(10) ..Temp co wise it might be worse.

The other alternative is an interlayer having intermediate tempco, to
spread the strain out. *For instance, stainless steel has a tempco
intermediate between aluminum and brass.

Grin.. yeah nice idea, but not for my application.

Here's a table of acoustic velocities and impedances.

http://ndtsystems.com/Reference/Velo...ity_table.html

George H.

Joe Gwinn- Hide quoted text -

- Show quoted text -

In article
,
George Herold wrote:

On Jun 29, 1:43*pm, Joseph Gwinn wrote:
In article
,
*George Herold wrote:





On Jun 29, 11:23*am, Joseph Gwinn wrote:
In article
,
*George Herold wrote:

(reposted from SED)
I want to try soldering some aluminum plate (0.032²) onto each side
of
a brass cylinder. *When trying to solder aluminum in the past I
failed. *I think I heard that some Al alloys are easier to solder
than
others. *I¹ve got a choice (From McMaster-C) of 6061, 2024. 7075, and
1100. * Any idea of which is better?

I was also planning on getting some aluminum flux and some Zn/tin
solder from McM-C. *Other suggestions welcome.

If the temperature coefficients of linear expansion of the brass and the
aluminum don't match to within something like 1%, the joint will surely
tear itself apart, no matter how well soldered the joint is.

Joe Gwinn

Hmm, OK thanks. *I was thinking of trying a thin layer of epoxy too.
But soldering would be better.
The linear expansion coef. of brass and Al differ by ~ 4E-6/C
http://en.wikipedia.org/wiki/Thermal_expansion#Thermal_expansion_coef...

So if soldering happens at 300C (?) then the thin aluminum plate has
to shrink by a part per thousand (or so). *Maybe 2 mils for a 1.5 inch
diameter cylinder. *I have no idea if a thin Al plate can accomidate
such strain. *(I'll find out.)

Would a nice soft alloy like 1100 be best?

If it's thin enough that it will yield.

But the acoustic loss may be high.


I have the impression that the area of the plate is large, and 1.5"
diameter is in the range. *A few mils may not sound like much, but when
metals fight, the stresses are large, and solder is weak.

The issue is that below the solidus temperature (where the solder
becomes solid) as the two metals cool they shrink differentially,
putting shear stress on the joint. *If the solder gives enough (which
depends on the max dimension between far points that are soldered), then
no problem. *Unless we have temperature cycling, which will fatigue the
solder and break the joint.

Rigid epoxy will also fail. *What can work is a silicon rubber adhesive,
so long as the adhesive layer is thick enough to accommodate the shear
strain without tearing.

Well I'll glue it at room temp and then use it at room temp, so maybe
not as much of a problem.


War story: *In the 1970s, I and a partner made lab instruments for
measuring how much drugged rats run around (yes, this is useful to
know). *The instrument consisted of a big sheet steel base about 12"
wide by about 24" long by maybe 4" high, with a milky plexiglass cover
glued to the top. *Light diffused through the plexiglass to light
receptors within the base. *The problem was that the glue joint between
plexiglass cover and steel base was breaking, despite use of the best of
adhesives (a silicon rubber adhesive caulk), the covers were coming
loose, and customers were unhappy.

Plexiglass has something like five times the temperature coefficient of
aluminum, never mind steel, so normal variation in temperature in the
customer labs was enough to tear the joints apart, even in labs with
only a few degrees of diurnal variation. *We measured the strength of
the joints - it was something like 50 or 100 pounds per inch in a lap
joint, and yet the joints broke within a year.

The solution was simple enough: *Put 1/16" thick spacers in the joints
so there was always enough rubber that it didn't tear as temperature
variation caused the cover to get larger and smaller compared to the
steel base.

Anyway, is there any reason the aluminum sheet cannot be brass instead?

Yeah I'm pretty much stuck with aluminum. (But I'm open to other
materials if there are any suggestions.) I just started these
acoustic experiments. I wanted to show impedance matching for
acoustics. (Like a 1/4 wavlength AR coating in optics.) I've got a
brass cylinder that's acting like an acoustic Fabry-Perot cavity.
There are transducers on each side (one source and the other
detector). The transducers have an acoustic impedance of about 3 (in
some units.) The brass has an impedcance of about 40 in the same
units.

I think acoustic impedances may be expressed in ohms as well. Although
it will depend on the system of units used.


So to make an AR coating I need 1/4 wavelength of a material
with a mean value between the two. (sqrt(3*40))= ~11.
Aluminum has an impedance of ~17 which seems to be close enough. I
should also try some glass which has about the right impedance.
(10) ..Temp co wise it might be worse.

The other alternative is an interlayer having intermediate tempco, to
spread the strain out. *For instance, stainless steel has a tempco
intermediate between aluminum and brass.

Grin.. yeah nice idea, but not for my application.

Here's a table of acoustic velocities and impedances.

http://ndtsystems.com/Reference/Velo...ity_table.html

Ahh. If the temperature range is small, epoxy will work, at least well
enough for experiments. One can get slightly flexible epoxy from
industrial suppliers like Master Bond and Loctite. They will know
what's best. The strongest materials require very good cleaning of
surfaces and cure at 250 F.

I have an old Bransonic ultrasonic cleaning unit with a stainless-steel
tank. The ceramic transducer is epoxied to an aluminum interplate which
is in turn epoxied directly the the stainless steel tank. This unit
still works after decades of use.

Is there any reason not to just drill and tap the brass and mechanically
attach the aluminum plate with a few steel screws, with some silicon
grease between brass and aluminum masses?

Joe Gwinn

On Jun 29, 6:48*am, George Herold wrote:
(reposted from SED)
I want to try soldering some aluminum plate (0.032”) onto each side
of
a brass cylinder. *When trying to solder aluminum in the past I
failed. *I think I heard that some Al alloys are easier to solder
than
others. *I’ve got a choice (From McMaster-C) of 6061, 2024. 7075, and
1100. * Any idea of which is better?

I was also planning on getting some aluminum flux and some Zn/tin
solder from McM-C. *Other suggestions welcome.

Thanks

George H.

It IS possible, but you have to use something to scratch through the
oxide coat first to bare aluminum. Usual practice is to puddle the
solder on the aluminum and use a stainless brush through the molten
solder until the surface is tinned, then sweat the other piece to it.
My Alcoa book suggests that the high zinc-content solders work the
best, another one recommends almost pure tin, go figure. Fluxes
usually have some really active content to dissolve the aluminum oxide
and will result in severe corrosion if not removed/neutralized.

If there's significant stress and it's a butt joint, you may have
cracking and joint failure. In that case you might need some
redesign, like going to solder tabs on your plates and maybe a thin
aluminum shrink-fit tube over your brass to solder to.

Stan

On Fri, 29 Jun 2012 15:29:46 -0400, Joseph Gwinn
wrote:

[...]

Ahh. If the temperature range is small, epoxy will work, at least well
enough for experiments. One can get slightly flexible epoxy from
industrial suppliers like Master Bond and Loctite. They will know
what's best. The strongest materials require very good cleaning of
surfaces and cure at 250 F.

I have an old Bransonic ultrasonic cleaning unit with a stainless-steel
tank. The ceramic transducer is epoxied to an aluminum interplate which
is in turn epoxied directly the the stainless steel tank. This unit
still works after decades of use.

Is there any reason not to just drill and tap the brass and mechanically
attach the aluminum plate with a few steel screws, with some silicon
grease between brass and aluminum masses?


I have not glued aluminum to brass but I have tried many adhesives for
gluing brass to other materials including other metals. I find that
most fail miserably.

The best for gluing steel to brass (which I do most often) is
Household Goop.

Michael Koblic,
Campbell River, BC

On Jun 29, 10:23*am, Joseph Gwinn wrote:
In article
,
*George Herold wrote:

(reposted from SED)
I want to try soldering some aluminum plate (0.032²) onto each side
of
a brass cylinder. *When trying to solder aluminum in the past I
failed. *I think I heard that some Al alloys are easier to solder
than
others. *I¹ve got a choice (From McMaster-C) of 6061, 2024. 7075, and
1100. * Any idea of which is better?

I was also planning on getting some aluminum flux and some Zn/tin
solder from McM-C. *Other suggestions welcome.

If the temperature coefficients of linear expansion of the brass and the
aluminum don't match to within something like 1%, the joint will surely
tear itself apart, no matter how well soldered the joint is.

Joe Gwinn

I looked to see if I could find for myself criteria for brazing of
dissimilar metals. I found this:
http://preview.tinyurl.com/6ndm7k3

I thought that a filler metal needed to be a material that could alloy
with the materials being joined. That's certainly the case with zinc,
brass and aluminum. It seems to be a complicated subject, but I
expect that he's on the right track (if he can control oxidation and
allow space for the filler and alloying).

For what it's worth, I also found this:
http://www.youtube.com/watch?v=lGy7pHx6P3Y

On Jun 29, 3:47*pm, Stanley Schaefer wrote:
On Jun 29, 6:48*am, George Herold wrote:

(reposted from SED)
I want to try soldering some aluminum plate (0.032”) onto each side
of
a brass cylinder. *When trying to solder aluminum in the past I
failed. *I think I heard that some Al alloys are easier to solder
than
others. *I’ve got a choice (From McMaster-C) of 6061, 2024. 7075, and
1100. * Any idea of which is better?

I was also planning on getting some aluminum flux and some Zn/tin
solder from McM-C. *Other suggestions welcome.

Thanks

George H.

It IS possible, but you have to use something to scratch through the
oxide coat first to bare aluminum. *Usual practice is to puddle the
solder on the aluminum and use a stainless brush through the molten
solder until the surface is tinned, then sweat the other piece to it.

Yeah, I figured I'd tin both sides and then mash 'em together..
(not sure exactly how to do the mashing, from center out at least.)

I never thought (or heard) of brushing it while under the solder,
Thanks!
My Alcoa book suggests that the high zinc-content solders work the
best, another one recommends almost pure tin, go figure. *Fluxes
usually have some really active content to dissolve the aluminum oxide
and will result in severe corrosion if not removed/neutralized.

Yeah.. been there with some SS fluxes. Should be fine if I can tin it
all nicely.


If there's significant stress and it's a butt joint, you may have
cracking and joint failure. *In that case you might need some
redesign, like going to solder tabs on your plates and maybe a thin
aluminum shrink-fit tube over your brass to solder to.

Well if solder doesn't work, then maybe some Al 'loaded' epoxy will,
'be the ticket'.


Stan

Thanks again Stan,

George H.

On Jun 29, 8:15*pm, wrote:
On Fri, 29 Jun 2012 15:29:46 -0400, Joseph Gwinn

wrote:

[...]

Ahh. *If the temperature range is small, epoxy will work, at least well
enough for experiments. *One can get slightly flexible epoxy from
industrial suppliers like Master Bond and Loctite. *They will know
what's best. *The strongest materials require very good cleaning of
surfaces and cure at 250 F.

I have an old Bransonic ultrasonic cleaning unit with a stainless-steel
tank. *The ceramic transducer is epoxied to an aluminum interplate which
is in turn epoxied directly the the stainless steel tank. *This unit
still works after decades of use.

Is there any reason not to just drill and tap the brass and mechanically
attach the aluminum plate with a few steel screws, with some silicon
grease between brass and aluminum masses?

I have not glued aluminum to brass but I have tried many adhesives for
gluing brass to other materials including other metals. I find that
most fail miserably.

The best for gluing steel to brass (which I do most often) is
Household Goop.

Michael Koblic,
Campbell River, BC

Hmm, Well in the deep dark past of grad school, we used stycast 1266
to glue Teflon 'washers' into TeCu plates.
Brass can't be that much different.

And there may be better epoxies by now.

George H.

In article
,
"Denis G." wrote:

On Jun 29, 10:23*am, Joseph Gwinn wrote:
In article
,
*George Herold wrote:

(reposted from SED)
I want to try soldering some aluminum plate (0.032²) onto each side
of
a brass cylinder. *When trying to solder aluminum in the past I
failed. *I think I heard that some Al alloys are easier to solder
than
others. *I¹ve got a choice (From McMaster-C) of 6061, 2024. 7075, and
1100. * Any idea of which is better?

I was also planning on getting some aluminum flux and some Zn/tin
solder from McM-C. *Other suggestions welcome.

If the temperature coefficients of linear expansion of the brass and the
aluminum don't match to within something like 1%, the joint will surely
tear itself apart, no matter how well soldered the joint is.

Joe Gwinn

I looked to see if I could find for myself criteria for brazing of
dissimilar metals. I found this:
http://preview.tinyurl.com/6ndm7k3

I thought that a filler metal needed to be a material that could alloy
with the materials being joined. That's certainly the case with zinc,
brass and aluminum. It seems to be a complicated subject, but I
expect that he's on the right track (if he can control oxidation and
allow space for the filler and alloying).

For what it's worth, I also found this:
http://www.youtube.com/watch?v=lGy7pHx6P3Y

Interesting book and webpage. I think I'll read the book.

The issue is not that one cannot braze metal X to metal Y. For the most
part, you can braze anything to anything. The issue is that if one does
not design to handle dissimilar temperature coefficients, the joint will
soon tear itself apart.

This is a big issue in high reliability engineering, especially in the
engineering of packages for semiconductors. There is an
accelerated-aging MIL-SPEC test for such things, where one alternately
plunges a part being tested into hot oil then liquid nitrogen. If
tempcos are not well matched, the part deconstructs itself. This is a
very severe test, but is a good predictor of future failure rate.
Especially in power electronics.

Joe Gwinn

In article ,
wrote:

On Fri, 29 Jun 2012 15:29:46 -0400, Joseph Gwinn
wrote:

[...]

Ahh. If the temperature range is small, epoxy will work, at least well
enough for experiments. One can get slightly flexible epoxy from
industrial suppliers like Master Bond and Loctite. They will know
what's best. The strongest materials require very good cleaning of
surfaces and cure at 250 F.

I have an old Bransonic ultrasonic cleaning unit with a stainless-steel
tank. The ceramic transducer is epoxied to an aluminum interplate which
is in turn epoxied directly the the stainless steel tank. This unit
still works after decades of use.

Is there any reason not to just drill and tap the brass and mechanically
attach the aluminum plate with a few steel screws, with some silicon
grease between brass and aluminum masses?


I have not glued aluminum to brass but I have tried many adhesives for
gluing brass to other materials including other metals. I find that
most fail miserably.

The best for gluing steel to brass (which I do most often) is
Household Goop.

I'm pretty sure it's a chemistry issue. For such things, one asks the
glue manufacturer. If I recall, brass is the problem.

Joe Gwinn

On Jun 29, 9:38*pm, Joseph Gwinn wrote:
In article
,
*"Denis G." wrote:









On Jun 29, 10:23*am, Joseph Gwinn wrote:
In article
,
*George Herold wrote:

(reposted from SED)
I want to try soldering some aluminum plate (0.032²) onto each side
of
a brass cylinder. *When trying to solder aluminum in the past I
failed. *I think I heard that some Al alloys are easier to solder
than
others. *I¹ve got a choice (From McMaster-C) of 6061, 2024. 7075, and
1100. * Any idea of which is better?

I was also planning on getting some aluminum flux and some Zn/tin
solder from McM-C. *Other suggestions welcome.

If the temperature coefficients of linear expansion of the brass and the
aluminum don't match to within something like 1%, the joint will surely
tear itself apart, no matter how well soldered the joint is.

Joe Gwinn

I looked to see if I could find for myself criteria for brazing of
dissimilar metals. *I found this:
http://preview.tinyurl.com/6ndm7k3

I thought that a filler metal needed to be a material that could alloy
with the materials being joined. *That's certainly the case with zinc,
brass and aluminum. *It seems to be a complicated subject, but I
expect that he's on the right track (if he can control oxidation and
allow space for the filler and alloying).

For what it's worth, I also found this:
http://www.youtube.com/watch?v=lGy7pHx6P3Y

Interesting book and webpage. *I think I'll read the book.

The issue is not that one cannot braze metal X to metal Y. *For the most
part, you can braze anything to anything. *The issue is that if one does
not design to handle dissimilar temperature coefficients, the joint will
soon tear itself apart.

This is a big issue in high reliability engineering, especially in the
engineering of packages for semiconductors. *There is an
accelerated-aging MIL-SPEC test for such things, where one alternately
plunges a part being tested into hot oil then liquid nitrogen. *If
tempcos are not well matched, the part deconstructs itself. *This is a
very severe test, but is a good predictor of future failure rate.
Especially in power electronics.

Joe Gwinn

I've a little bit of experience with HAST, but nothing as severe as
what you describe. Military stuff is always pushing the limits.

On Jun 29, 9:09*pm, "Denis G." wrote:
On Jun 29, 10:23*am, Joseph Gwinn wrote:





In article
,
*George Herold wrote:

(reposted from SED)
I want to try soldering some aluminum plate (0.032²) onto each side
of
a brass cylinder. *When trying to solder aluminum in the past I
failed. *I think I heard that some Al alloys are easier to solder
than
others. *I¹ve got a choice (From McMaster-C) of 6061, 2024. 7075, and
1100. * Any idea of which is better?

I was also planning on getting some aluminum flux and some Zn/tin
solder from McM-C. *Other suggestions welcome.

If the temperature coefficients of linear expansion of the brass and the
aluminum don't match to within something like 1%, the joint will surely
tear itself apart, no matter how well soldered the joint is.

Joe Gwinn

I looked to see if I could find for myself criteria for brazing of
dissimilar metals. *I found this:http://preview.tinyurl.com/6ndm7k3

I thought that a filler metal needed to be a material that could alloy
with the materials being joined. *That's certainly the case with zinc,
brass and aluminum. *It seems to be a complicated subject, but I
expect that he's on the right track (if he can control oxidation and
allow space for the filler and alloying).

For what it's worth, I also found this:http://www.youtube.com/watch?v=lGy7pHx6P3Y- Hide quoted text -

- Show quoted text -

The brass part could be changed. Bronze, TeCu, BeCu if any might be
better?

An Al puck in an oversized hole is an interesting idea.
I assume the solder will shrink less than the Al,
Do I want the puck to be pulled from the sides as well as the face?

George H.

On Fri, 29 Jun 2012 19:15:13 -0700 (PDT), George Herold
wrote:

On Jun 29, 3:47*pm, Stanley Schaefer wrote:
On Jun 29, 6:48*am, George Herold wrote:

(reposted from SED)
I want to try soldering some aluminum plate (0.032”) onto each side
of
a brass cylinder. *When trying to solder aluminum in the past I
failed. *I think I heard that some Al alloys are easier to solder
than
others. *I’ve got a choice (From McMaster-C) of 6061, 2024. 7075, and
1100. * Any idea of which is better?

I was also planning on getting some aluminum flux and some Zn/tin
solder from McM-C. *Other suggestions welcome.

Thanks

George H.

It IS possible, but you have to use something to scratch through the
oxide coat first to bare aluminum. *Usual practice is to puddle the
solder on the aluminum and use a stainless brush through the molten
solder until the surface is tinned, then sweat the other piece to it.

Yeah, I figured I'd tin both sides and then mash 'em together..
(not sure exactly how to do the mashing, from center out at least.)

I never thought (or heard) of brushing it while under the solder,
Thanks!
My Alcoa book suggests that the high zinc-content solders work the
best, another one recommends almost pure tin, go figure. *Fluxes
usually have some really active content to dissolve the aluminum oxide
and will result in severe corrosion if not removed/neutralized.

Yeah.. been there with some SS fluxes. Should be fine if I can tin it
all nicely.


If there's significant stress and it's a butt joint, you may have
cracking and joint failure. *In that case you might need some
redesign, like going to solder tabs on your plates and maybe a thin
aluminum shrink-fit tube over your brass to solder to.

Well if solder doesn't work, then maybe some Al 'loaded' epoxy will,
'be the ticket'.


Stan

Thanks again Stan,

George H.
Greetings George,
What Stan says about scratching the surface through the solder is
right on. You can solder without any flux at all. I have used the
aluminum solders available at the hardware store and the strength is
remarkable. You can buy little stainless brushes that are about the
size of a toothbrush at the hardware store too. Once the surface is
tinned it is easy to solder to anything else. If it was me I would
avoid the use of flux on the aluminum just for ease of cleaning. Once
the solder is molten and you start scratching the aluminum through the
solder you will see that the solder will follow the brush as the
brush moves beyond the area initially covered with solder.
Eric

"George Herold" wrote in message
...
On Jun 29, 3:47 pm, Stanley Schaefer wrote:
On Jun 29, 6:48 am, George Herold wrote:

(reposted from SED)
I want to try soldering some aluminum plate (0.032”) onto each side
of
a brass cylinder. When trying to solder aluminum in the past I
failed. I think I heard that some Al alloys are easier to solder
than
others. I’ve got a choice (From McMaster-C) of 6061, 2024. 7075, and
1100. Any idea of which is better?

I was also planning on getting some aluminum flux and some Zn/tin
solder from McM-C. Other suggestions welcome.

Thanks

George H.

It IS possible, but you have to use something to scratch through the
oxide coat first to bare aluminum. Usual practice is to puddle the
solder on the aluminum and use a stainless brush through the molten
solder until the surface is tinned, then sweat the other piece to it.

Yeah, I figured I'd tin both sides and then mash 'em together..
(not sure exactly how to do the mashing, from center out at least.)

I never thought (or heard) of brushing it while under the solder,
Thanks!
My Alcoa book suggests that the high zinc-content solders work the
best, another one recommends almost pure tin, go figure. Fluxes
usually have some really active content to dissolve the aluminum oxide
and will result in severe corrosion if not removed/neutralized.

Yeah.. been there with some SS fluxes. Should be fine if I can tin it
all nicely.


If there's significant stress and it's a butt joint, you may have
cracking and joint failure. In that case you might need some
redesign, like going to solder tabs on your plates and maybe a thin
aluminum shrink-fit tube over your brass to solder to.

Well if solder doesn't work, then maybe some Al 'loaded' epoxy will,
'be the ticket'.


Stan

Thanks again Stan,

George H.

Since gluing is a possibility then there are a lot of other options. First,
a press fit plug would probably be the best.
If you want to solder, I wouldn't dick around with the zinc stuff. Get some
La-Co Aluminum flux. This is for lead/tin solders. Scrape the aluminum clean
and apply the flux (I usually scrape some more under cover of the flux) then
tin the aluminum with regular plumbers solder. Tin the brass with whatever
flux you prefer. Then clean both parts, apply regular flux and sweat them
together. Practice with the La-Co on some scrap until you get your technique
down.

If you want to glue, epoxy is a pain to bond with AL. The best stuff is an 2
part acrylic from Lord #406/16.
This is the stuff they glue airplanes together with. You need a special
dispenser gun and the first use is pretty spendy, but if you ever get a
chance to try it you will be amazed at how well it works.

Paul K. Dickman

On 6/29/2012 9:24 PM, George Herold wrote:
On Jun 29, 8:15 pm, wrote:
On Fri, 29 Jun 2012 15:29:46 -0400, Joseph Gwinn

wrote:

[...]

Ahh. If the temperature range is small, epoxy will work, at least well
enough for experiments. One can get slightly flexible epoxy from
industrial suppliers like Master Bond and Loctite. They will know
what's best. The strongest materials require very good cleaning of
surfaces and cure at 250 F.

I have an old Bransonic ultrasonic cleaning unit with a stainless-steel
tank. The ceramic transducer is epoxied to an aluminum interplate which
is in turn epoxied directly the the stainless steel tank. This unit
still works after decades of use.

Is there any reason not to just drill and tap the brass and mechanically
attach the aluminum plate with a few steel screws, with some silicon
grease between brass and aluminum masses?

I have not glued aluminum to brass but I have tried many adhesives for
gluing brass to other materials including other metals. I find that
most fail miserably.

The best for gluing steel to brass (which I do most often) is
Household Goop.

Michael Koblic,
Campbell River, BC

Hmm, Well in the deep dark past of grad school, we used stycast 1266
to glue Teflon 'washers' into TeCu plates.
Brass can't be that much different.

And there may be better epoxies by now.

George H.


Nope.

Goop, pick your favorite flavor.

Personally I prefer Plumbers Goop for this job - thinner and easier to
spread evenly.

On Sat, 30 Jun 2012 12:29:36 -0500, Richard
wrote:

Hmm, Well in the deep dark past of grad school, we used stycast 1266
to glue Teflon 'washers' into TeCu plates.
Brass can't be that much different.

And there may be better epoxies by now.

George H.


Nope.

Goop, pick your favorite flavor.

Personally I prefer Plumbers Goop for this job - thinner and easier to
spread evenly.

Yes. The difference between theory and practice.
I will have a look at Plumbers' Goop. Never tried it.

Michael Koblic,
Campbell River, BC

On Fri, 29 Jun 2012 22:40:23 -0400, Joseph Gwinn
wrote:

[...]

The best for gluing steel to brass (which I do most often) is
Household Goop.

I'm pretty sure it's a chemistry issue. For such things, one asks the
glue manufacturer. If I recall, brass is the problem.


The glue manufacturers I asked did not have a dicky. Indeed brass is
the problem. It does not matter how you pre-treat it. Incantations and
saying Lord' prayer backwards does not work either.

Just Goop.

Michael Koblic,
Campbell River, BC

On Sat, 30 Jun 2012 09:10:21 -0700, wrote:

On Fri, 29 Jun 2012 19:15:13 -0700 (PDT), George Herold
wrote:

On Jun 29, 3:47Â*pm, Stanley Schaefer wrote:
On Jun 29, 6:48Â*am, George Herold wrote:

(reposted from SED)
I want to try soldering some aluminum plate (0.032€�) onto each side
of
a brass cylinder. Â*When trying to solder aluminum in the past I
failed. Â*I think I heard that some Al alloys are easier to solder
than
others. Â*Ive got a choice (From McMaster-C) of 6061, 2024. 7075, and
1100. Â* Any idea of which is better?

I was also planning on getting some aluminum flux and some Zn/tin
solder from McM-C. Â*Other suggestions welcome.

Thanks

George H.

It IS possible, but you have to use something to scratch through the
oxide coat first to bare aluminum. Â*Usual practice is to puddle the
solder on the aluminum and use a stainless brush through the molten
solder until the surface is tinned, then sweat the other piece to it.

Yeah, I figured I'd tin both sides and then mash 'em together..
(not sure exactly how to do the mashing, from center out at least.)

I never thought (or heard) of brushing it while under the solder,
Thanks!
My Alcoa book suggests that the high zinc-content solders work the
best, another one recommends almost pure tin, go figure. Â*Fluxes
usually have some really active content to dissolve the aluminum oxide
and will result in severe corrosion if not removed/neutralized.

Yeah.. been there with some SS fluxes. Should be fine if I can tin it
all nicely.


If there's significant stress and it's a butt joint, you may have
cracking and joint failure. Â*In that case you might need some
redesign, like going to solder tabs on your plates and maybe a thin
aluminum shrink-fit tube over your brass to solder to.

Well if solder doesn't work, then maybe some Al 'loaded' epoxy will,
'be the ticket'.


Stan

Thanks again Stan,

George H.
Greetings George,
What Stan says about scratching the surface through the solder is
right on. You can solder without any flux at all. I have used the
aluminum solders available at the hardware store and the strength is
remarkable. You can buy little stainless brushes that are about the
size of a toothbrush at the hardware store too. Once the surface is
tinned it is easy to solder to anything else. If it was me I would
avoid the use of flux on the aluminum just for ease of cleaning. Once
the solder is molten and you start scratching the aluminum through the
solder you will see that the solder will follow the brush as the
brush moves beyond the area initially covered with solder.
Eric
Another trick is to sand the aluminum clean and OIL it, then solder.
Vegatable oil, kerosine, WD-40, or motor oil will all work. do the
final cleaning/sandong/wire-brushing through the oil and it can't
oxidize so the solder tins the aluminum very easily. After it is
tinned you can solder anything to it.

On Sat, 30 Jun 2012 13:53:45 -0700, wrote:

On Fri, 29 Jun 2012 22:40:23 -0400, Joseph Gwinn
wrote:

[...]

The best for gluing steel to brass (which I do most often) is
Household Goop.

I'm pretty sure it's a chemistry issue. For such things, one asks the
glue manufacturer. If I recall, brass is the problem.


The glue manufacturers I asked did not have a dicky. Indeed brass is
the problem. It does not matter how you pre-treat it. Incantations and
saying Lord' prayer backwards does not work either.

Just Goop.

Michael Koblic,
Campbell River, BC
You saying BRASS is difficult to solder?????

On Sat, 30 Jun 2012 21:15:57 -0400, wrote:

On Sat, 30 Jun 2012 09:10:21 -0700, wrote:

On Fri, 29 Jun 2012 19:15:13 -0700 (PDT), George Herold
wrote:

On Jun 29, 3:47*pm, Stanley Schaefer wrote:
On Jun 29, 6:48*am, George Herold wrote:

(reposted from SED)
I want to try soldering some aluminum plate (0.032”) onto each side
of
a brass cylinder. *When trying to solder aluminum in the past I
failed. *I think I heard that some Al alloys are easier to solder
than
others. *I’ve got a choice (From McMaster-C) of 6061, 2024. 7075, and
1100. * Any idea of which is better?

I was also planning on getting some aluminum flux and some Zn/tin
solder from McM-C. *Other suggestions welcome.

Thanks

George H.

It IS possible, but you have to use something to scratch through the
oxide coat first to bare aluminum. *Usual practice is to puddle the
solder on the aluminum and use a stainless brush through the molten
solder until the surface is tinned, then sweat the other piece to it.

Yeah, I figured I'd tin both sides and then mash 'em together..
(not sure exactly how to do the mashing, from center out at least.)

I never thought (or heard) of brushing it while under the solder,
Thanks!
My Alcoa book suggests that the high zinc-content solders work the
best, another one recommends almost pure tin, go figure. *Fluxes
usually have some really active content to dissolve the aluminum oxide
and will result in severe corrosion if not removed/neutralized.

Yeah.. been there with some SS fluxes. Should be fine if I can tin it
all nicely.


If there's significant stress and it's a butt joint, you may have
cracking and joint failure. *In that case you might need some
redesign, like going to solder tabs on your plates and maybe a thin
aluminum shrink-fit tube over your brass to solder to.

Well if solder doesn't work, then maybe some Al 'loaded' epoxy will,
'be the ticket'.


Stan

Thanks again Stan,

George H.
Greetings George,
What Stan says about scratching the surface through the solder is
right on. You can solder without any flux at all. I have used the
aluminum solders available at the hardware store and the strength is
remarkable. You can buy little stainless brushes that are about the
size of a toothbrush at the hardware store too. Once the surface is
tinned it is easy to solder to anything else. If it was me I would
avoid the use of flux on the aluminum just for ease of cleaning. Once
the solder is molten and you start scratching the aluminum through the
solder you will see that the solder will follow the brush as the
brush moves beyond the area initially covered with solder.
Eric
Another trick is to sand the aluminum clean and OIL it, then solder.
Vegatable oil, kerosine, WD-40, or motor oil will all work. do the
final cleaning/sandong/wire-brushing through the oil and it can't
oxidize so the solder tins the aluminum very easily. After it is
tinned you can solder anything to it.
I tried for the first time recently some tinning flux for plumbing.
This is the flux that has the finely ground nonleaded silver bearing
solder mixed with the flux. It worked very well for a non plumbing job
soldering manganese bronze. I'm gonna try it today on aluminum with
the wire brush trick, like the oil trick above. I'll post the results
here.
Eric

In article ,
wrote:

On Sat, 30 Jun 2012 13:53:45 -0700, wrote:

On Fri, 29 Jun 2012 22:40:23 -0400, Joseph Gwinn
wrote:

[...]

The best for gluing steel to brass (which I do most often) is
Household Goop.

I'm pretty sure it's a chemistry issue. For such things, one asks the
glue manufacturer. If I recall, brass is the problem.


The glue manufacturers I asked did not have a dicky. Indeed brass is
the problem. It does not matter how you pre-treat it. Incantations and
saying Lord' prayer backwards does not work either.

Just Goop.

Michael Koblic,
Campbell River, BC
You saying BRASS is difficult to solder?????

No, glue. I think the zinc reacts badly with some kinds of adhesives.
Aluminum has this problem too. Anyway, there are glues that work, and
glues that don't work.

Joe Gwinn

On 7/1/2012 11:46 AM, Joseph Gwinn wrote:
In ,
wrote:

On Sat, 30 Jun 2012 13:53:45 -0700, wrote:

On Fri, 29 Jun 2012 22:40:23 -0400, Joseph Gwinn
wrote:

[...]

The best for gluing steel to brass (which I do most often) is
Household Goop.

I'm pretty sure it's a chemistry issue. For such things, one asks the
glue manufacturer. If I recall, brass is the problem.


The glue manufacturers I asked did not have a dicky. Indeed brass is
the problem. It does not matter how you pre-treat it. Incantations and
saying Lord' prayer backwards does not work either.

Just Goop.

Michael Koblic,
Campbell River, BC
You saying BRASS is difficult to solder?????

No, glue. I think the zinc reacts badly with some kinds of adhesives.
Aluminum has this problem too. Anyway, there are glues that work, and
glues that don't work.

Joe Gwinn


There are techniques that work as well, not just adhesives.

For instance, for aluminum...
The problem is that aluminum grows an oxide layer is just a few seconds.
So what you have to do is prep the oxide layer and bond to that.
Phosphate wash followed by two-part primer like EpiBond or Randoplate.
Now your glue can bond to the primer and get some adhesion.

Urethane glues will actually work with the primer, Looks like it
dissolves into the primer.

But for general bonding metal to metal, pick a Goop, any Goop,
and stick with it.

In article ,
Richard wrote:

On 7/1/2012 11:46 AM, Joseph Gwinn wrote:
In ,
wrote:

On Sat, 30 Jun 2012 13:53:45 -0700, wrote:

On Fri, 29 Jun 2012 22:40:23 -0400, Joseph Gwinn
wrote:

[...]

The best for gluing steel to brass (which I do most often) is
Household Goop.

I'm pretty sure it's a chemistry issue. For such things, one asks the
glue manufacturer. If I recall, brass is the problem.


The glue manufacturers I asked did not have a dicky. Indeed brass is
the problem. It does not matter how you pre-treat it. Incantations and
saying Lord' prayer backwards does not work either.

Just Goop.

Michael Koblic,
Campbell River, BC
You saying BRASS is difficult to solder?????

No, glue. I think the zinc reacts badly with some kinds of adhesives.
Aluminum has this problem too. Anyway, there are glues that work, and
glues that don't work.

Joe Gwinn


There are techniques that work as well, not just adhesives.

For instance, for aluminum...
The problem is that aluminum grows an oxide layer is just a few seconds.
So what you have to do is prep the oxide layer and bond to that.
Phosphate wash followed by two-part primer like EpiBond or Randoplate.
Now your glue can bond to the primer and get some adhesion.

Urethane glues will actually work with the primer, Looks like it
dissolves into the primer.

But for general bonding metal to metal, pick a Goop, any Goop,
and stick with it.

How does this work for people to metal?

On 7/1/2012 3:00 PM, Joseph Gwinn wrote:
In articleoemdndDN_PfxDm3SnZ2dnUVZ_vudnZ2d@earthlink .com,
wrote:

On 7/1/2012 11:46 AM, Joseph Gwinn wrote:
In ,
wrote:

On Sat, 30 Jun 2012 13:53:45 -0700, wrote:

On Fri, 29 Jun 2012 22:40:23 -0400, Joseph Gwinn
wrote:

[...]

The best for gluing steel to brass (which I do most often) is
Household Goop.

I'm pretty sure it's a chemistry issue. For such things, one asks the
glue manufacturer. If I recall, brass is the problem.


The glue manufacturers I asked did not have a dicky. Indeed brass is
the problem. It does not matter how you pre-treat it. Incantations and
saying Lord' prayer backwards does not work either.

Just Goop.

Michael Koblic,
Campbell River, BC
You saying BRASS is difficult to solder?????

No, glue. I think the zinc reacts badly with some kinds of adhesives.
Aluminum has this problem too. Anyway, there are glues that work, and
glues that don't work.

Joe Gwinn


There are techniques that work as well, not just adhesives.

For instance, for aluminum...
The problem is that aluminum grows an oxide layer is just a few seconds.
So what you have to do is prep the oxide layer and bond to that.
Phosphate wash followed by two-part primer like EpiBond or Randoplate.
Now your glue can bond to the primer and get some adhesion.

Urethane glues will actually work with the primer, Looks like it
dissolves into the primer.

But for general bonding metal to metal, pick a Goop, any Goop,
and stick with it.

How does this work for people to metal?

Cyanoacrylate. Glues people to almost anything.

In article ,
Richard wrote:

On 7/1/2012 3:00 PM, Joseph Gwinn wrote:
In articleoemdndDN_PfxDm3SnZ2dnUVZ_vudnZ2d@earthlink .com,
wrote:

On 7/1/2012 11:46 AM, Joseph Gwinn wrote:
In ,
wrote:

On Sat, 30 Jun 2012 13:53:45 -0700, wrote:

On Fri, 29 Jun 2012 22:40:23 -0400, Joseph Gwinn
wrote:

[...]

The best for gluing steel to brass (which I do most often) is
Household Goop.

I'm pretty sure it's a chemistry issue. For such things, one asks the
glue manufacturer. If I recall, brass is the problem.


The glue manufacturers I asked did not have a dicky. Indeed brass is
the problem. It does not matter how you pre-treat it. Incantations and
saying Lord' prayer backwards does not work either.

Just Goop.

Michael Koblic,
Campbell River, BC
You saying BRASS is difficult to solder?????

No, glue. I think the zinc reacts badly with some kinds of adhesives.
Aluminum has this problem too. Anyway, there are glues that work, and
glues that don't work.

Joe Gwinn


There are techniques that work as well, not just adhesives.

For instance, for aluminum...
The problem is that aluminum grows an oxide layer is just a few seconds.
So what you have to do is prep the oxide layer and bond to that.
Phosphate wash followed by two-part primer like EpiBond or Randoplate.
Now your glue can bond to the primer and get some adhesion.

Urethane glues will actually work with the primer, Looks like it
dissolves into the primer.

But for general bonding metal to metal, pick a Goop, any Goop,
and stick with it.

How does this work for people to metal?

Cyanoacrylate. Glues people to almost anything.

Yes, but Goop?

On Jun 30, 12:10*pm, wrote:
On Fri, 29 Jun 2012 19:15:13 -0700 (PDT), George Herold





wrote:
On Jun 29, 3:47*pm, Stanley Schaefer wrote:
On Jun 29, 6:48*am, George Herold wrote:

(reposted from SED)
I want to try soldering some aluminum plate (0.032”) onto each side
of
a brass cylinder. *When trying to solder aluminum in the past I
failed. *I think I heard that some Al alloys are easier to solder
than
others. *I’ve got a choice (From McMaster-C) of 6061, 2024. 7075, and
1100. * Any idea of which is better?

I was also planning on getting some aluminum flux and some Zn/tin
solder from McM-C. *Other suggestions welcome.

Thanks

George H.

It IS possible, but you have to use something to scratch through the
oxide coat first to bare aluminum. *Usual practice is to puddle the
solder on the aluminum and use a stainless brush through the molten
solder until the surface is tinned, then sweat the other piece to it.

Yeah, I figured I'd tin both sides and then mash 'em together..
(not sure exactly how to do the mashing, from center out at least.)

I never thought (or heard) of brushing it while under the solder,
Thanks!
My Alcoa book suggests that the high zinc-content solders work the
best, another one recommends almost pure tin, go figure. *Fluxes
usually have some really active content to dissolve the aluminum oxide
and will result in severe corrosion if not removed/neutralized.

Yeah.. been there with some SS fluxes. *Should be fine if I can tin it
all nicely.

If there's significant stress and it's a butt joint, you may have
cracking and joint failure. *In that case you might need some
redesign, like going to solder tabs on your plates and maybe a thin
aluminum shrink-fit tube over your brass to solder to.

Well if solder doesn't work, then maybe some Al 'loaded' epoxy will,
'be the ticket'.

Stan

Thanks again Stan,

George H.

Greetings George,
What Stan says about scratching the surface through the solder is
right on. You can solder without any flux at all. I have used the
aluminum solders available at the hardware store and the strength is
remarkable. You can buy little stainless brushes that are about the
size of a toothbrush at the hardware store too. Once the surface is
tinned it is easy to solder to anything else. If it was me I would
avoid the use of flux on the aluminum just for ease of cleaning. Once
the solder is molten and you start scratching the aluminum through the
solder you *will see that the solder will follow the brush as the
brush moves beyond the area initially covered with solder.
Eric- Hide quoted text -

- Show quoted text -

Thanks Eric that sound promising.

George H.

On Jun 30, 12:50*pm, "Paul K. Dickman"
wrote:
"George Herold" wrote in message

snip previuos stuff

George H.

Since gluing is a possibility then there are a lot of other options. First,
a press fit plug would probably be the best.

Hi Paul, I need a good 'acoustic' joint between the two materials. I
can see a press fit giving good contact around the perimeter, but I
don't know about the two faces. What (I think*) I want is to get rid
of all the air gaps at the boundary. I've been using this ultra sonic
'goop' between the layers, the quality of the coupling depends on
squezzing hard and having the absolute minimum of 'goop'.

If you want to solder, I wouldn't dick around with the zinc stuff. Get some
La-Co Aluminum flux. This is for lead/tin solders. Scrape the aluminum clean
and apply the flux (I usually scrape some more under cover of the flux) then
tin the aluminum with regular plumbers solder. Tin the brass with whatever
flux you prefer. Then clean both parts, apply regular flux and sweat them
together. Practice with the La-Co on some scrap until you get your technique
down.

OK, that looks like an option. I'll order some. (I already committed
to dicking around with the zinc stuff... can't just let it go to
waste.)


If you want to glue, epoxy is a pain to bond with AL. The best stuff is an 2
part acrylic from Lord #406/16.
This is the stuff they glue airplanes together with. You need a special
dispenser gun and the first use is pretty spendy, but if you ever get a
chance to try it you will be amazed at how well it works.

Hmm, did you mean Lord 406/19. There's a lot of that on the web.

Here I was thinking that gluing would be the easy alternative, but the
advice I'm recieveing seems to suggest that it may be harder than I
thought.

Thanks for the wisdom.. at the moment I'll keep the Lord stuff as a
back up plan,
(If all the more commone epoxies we have laying around fail.)

George H.

*I've just started with this acoustic 'gizmo' so....


Paul K. Dickman- Hide quoted text -

- Show quoted text -

On Jun 30, 1:29*pm, Richard wrote:
On 6/29/2012 9:24 PM, George Herold wrote:





On Jun 29, 8:15 pm, wrote:
On Fri, 29 Jun 2012 15:29:46 -0400, Joseph Gwinn

*wrote:

[...]

Ahh. *If the temperature range is small, epoxy will work, at least well
enough for experiments. *One can get slightly flexible epoxy from
industrial suppliers like Master Bond and Loctite. *They will know
what's best. *The strongest materials require very good cleaning of
surfaces and cure at 250 F.

I have an old Bransonic ultrasonic cleaning unit with a stainless-steel
tank. *The ceramic transducer is epoxied to an aluminum interplate which
is in turn epoxied directly the the stainless steel tank. *This unit
still works after decades of use.

Is there any reason not to just drill and tap the brass and mechanically
attach the aluminum plate with a few steel screws, with some silicon
grease between brass and aluminum masses?

I have not glued aluminum to brass but I have tried many adhesives for
gluing brass to other materials including other metals. I find that
most fail miserably.

The best for gluing steel to brass (which I do most often) is
Household Goop.

Michael Koblic,
Campbell River, BC

Hmm, *Well in the deep dark past of grad school, we used stycast 1266
to glue Teflon 'washers' into TeCu plates.
Brass can't be that much different.

And there may be better epoxies by now.

George H.

Nope.

Goop, pick your favorite flavor.

Personally I prefer Plumbers Goop for this job - thinner and easier to
spread evenly.- Hide quoted text -

- Show quoted text -

Ahh OK, I'll give it a try if the soldering doesn't work.

Say will the plumbers goop work if the surface is wet?
(I've got this Intex blue plastic pool for the kids.
I noticed a little pin hole leak in the side wall.
I stuck the every present duct tape on it, which has reduced it to a
trickle, but...)

George H.

On Jun 30, 9:15*pm, wrote:
On Sat, 30 Jun 2012 09:10:21 -0700, wrote:
On Fri, 29 Jun 2012 19:15:13 -0700 (PDT), George Herold
wrote:

On Jun 29, 3:47*pm, Stanley Schaefer wrote:
On Jun 29, 6:48*am, George Herold wrote:

(reposted from SED)
I want to try soldering some aluminum plate (0.032”) onto each side
of
a brass cylinder. *When trying to solder aluminum in the past I
failed. *I think I heard that some Al alloys are easier to solder
than
others. *I’ve got a choice (From McMaster-C) of 6061, 2024. 7075, and
1100. * Any idea of which is better?

I was also planning on getting some aluminum flux and some Zn/tin
solder from McM-C. *Other suggestions welcome.

Thanks

George H.

It IS possible, but you have to use something to scratch through the
oxide coat first to bare aluminum. *Usual practice is to puddle the
solder on the aluminum and use a stainless brush through the molten
solder until the surface is tinned, then sweat the other piece to it.

Yeah, I figured I'd tin both sides and then mash 'em together..
(not sure exactly how to do the mashing, from center out at least.)

I never thought (or heard) of brushing it while under the solder,
Thanks!
My Alcoa book suggests that the high zinc-content solders work the
best, another one recommends almost pure tin, go figure. *Fluxes
usually have some really active content to dissolve the aluminum oxide
and will result in severe corrosion if not removed/neutralized.

Yeah.. been there with some SS fluxes. *Should be fine if I can tin it
all nicely.

If there's significant stress and it's a butt joint, you may have
cracking and joint failure. *In that case you might need some
redesign, like going to solder tabs on your plates and maybe a thin
aluminum shrink-fit tube over your brass to solder to.

Well if solder doesn't work, then maybe some Al 'loaded' epoxy will,
'be the ticket'.

Stan

Thanks again Stan,

George H.
Greetings George,
What Stan says about scratching the surface through the solder is
right on. You can solder without any flux at all. I have used the
aluminum solders available at the hardware store and the strength is
remarkable. You can buy little stainless brushes that are about the
size of a toothbrush at the hardware store too. Once the surface is
tinned it is easy to solder to anything else. If it was me I would
avoid the use of flux on the aluminum just for ease of cleaning. Once
the solder is molten and you start scratching the aluminum through the
solder you *will see that the solder will follow the brush as the
brush moves beyond the area initially covered with solder.
Eric

* Another trick is to sand the aluminum clean and OIL it, then solder.
Vegatable oil, kerosine, WD-40, or motor oil will all work. do the
final cleaning/sandong/wire-brushing through the oil and it can't
oxidize so the solder tins the aluminum very easily. After it is
tinned you can solder anything to it.- Hide quoted text -

- Show quoted text -

Interesting idea, Thanks

George H.

On Mon, 2 Jul 2012 06:29:56 -0700 (PDT), George Herold
wrote:

On Jun 30, 12:10*pm, wrote:
On Fri, 29 Jun 2012 19:15:13 -0700 (PDT), George Herold





wrote:
On Jun 29, 3:47*pm, Stanley Schaefer wrote:
On Jun 29, 6:48*am, George Herold wrote:

(reposted from SED)
I want to try soldering some aluminum plate (0.032”) onto each side
of
a brass cylinder. *When trying to solder aluminum in the past I
failed. *I think I heard that some Al alloys are easier to solder
than
others. *I’ve got a choice (From McMaster-C) of 6061, 2024. 7075, and
1100. * Any idea of which is better?

I was also planning on getting some aluminum flux and some Zn/tin
solder from McM-C. *Other suggestions welcome.

Thanks

George H.

It IS possible, but you have to use something to scratch through the
oxide coat first to bare aluminum. *Usual practice is to puddle the
solder on the aluminum and use a stainless brush through the molten
solder until the surface is tinned, then sweat the other piece to it.

Yeah, I figured I'd tin both sides and then mash 'em together..
(not sure exactly how to do the mashing, from center out at least.)

I never thought (or heard) of brushing it while under the solder,
Thanks!
My Alcoa book suggests that the high zinc-content solders work the
best, another one recommends almost pure tin, go figure. *Fluxes
usually have some really active content to dissolve the aluminum oxide
and will result in severe corrosion if not removed/neutralized.

Yeah.. been there with some SS fluxes. *Should be fine if I can tin it
all nicely.

If there's significant stress and it's a butt joint, you may have
cracking and joint failure. *In that case you might need some
redesign, like going to solder tabs on your plates and maybe a thin
aluminum shrink-fit tube over your brass to solder to.

Well if solder doesn't work, then maybe some Al 'loaded' epoxy will,
'be the ticket'.

Stan

Thanks again Stan,

George H.

Greetings George,
What Stan says about scratching the surface through the solder is
right on. You can solder without any flux at all. I have used the
aluminum solders available at the hardware store and the strength is
remarkable. You can buy little stainless brushes that are about the
size of a toothbrush at the hardware store too. Once the surface is
tinned it is easy to solder to anything else. If it was me I would
avoid the use of flux on the aluminum just for ease of cleaning. Once
the solder is molten and you start scratching the aluminum through the
solder you *will see that the solder will follow the brush as the
brush moves beyond the area initially covered with solder.
Eric- Hide quoted text -

- Show quoted text -

Thanks Eric that sound promising.

George H.
You're welcome. I hope it helps.

On Mon, 2 Jul 2012 07:13:19 -0700 (PDT), George Herold
wrote:

On Jun 30, 1:29Â*pm, Richard wrote:
On 6/29/2012 9:24 PM, George Herold wrote:





On Jun 29, 8:15 pm, wrote:
On Fri, 29 Jun 2012 15:29:46 -0400, Joseph Gwinn

Â*wrote:

[...]

Ahh. Â*If the temperature range is small, epoxy will work, at least well
enough for experiments. Â*One can get slightly flexible epoxy from
industrial suppliers like Master Bond and Loctite. Â*They will know
what's best. Â*The strongest materials require very good cleaning of
surfaces and cure at 250 F.

I have an old Bransonic ultrasonic cleaning unit with a stainless-steel
tank. Â*The ceramic transducer is epoxied to an aluminum interplate which
is in turn epoxied directly the the stainless steel tank. Â*This unit
still works after decades of use.

Is there any reason not to just drill and tap the brass and mechanically
attach the aluminum plate with a few steel screws, with some silicon
grease between brass and aluminum masses?

I have not glued aluminum to brass but I have tried many adhesives for
gluing brass to other materials including other metals. I find that
most fail miserably.

The best for gluing steel to brass (which I do most often) is
Household Goop.

Michael Koblic,
Campbell River, BC

Hmm, Â*Well in the deep dark past of grad school, we used stycast 1266
to glue Teflon 'washers' into TeCu plates.
Brass can't be that much different.

And there may be better epoxies by now.

George H.

Nope.

Goop, pick your favorite flavor.

Personally I prefer Plumbers Goop for this job - thinner and easier to
spread evenly.- Hide quoted text -

- Show quoted text -

Ahh OK, I'll give it a try if the soldering doesn't work.

Say will the plumbers goop work if the surface is wet?
(I've got this Intex blue plastic pool for the kids.
I noticed a little pin hole leak in the side wall.
I stuck the every present duct tape on it, which has reduced it to a
trickle, but...)

George H.
"Seal All" is your friend for that application. From Ecclectic
Products - same company that sells ShoeGoo AND goop- A SUBSIDIARY OF
WHILLAMETTE VALLEY CORP

"Gunner Asch" wrote in message
...
On Sun, 01 Jul 2012 23:19:48 -0500, Richard
wrote:

On 7/1/2012 3:00 PM, Joseph Gwinn wrote:
In articleoemdndDN_PfxDm3SnZ2dnUVZ_vudnZ2d@earthlink .com,
wrote:

On 7/1/2012 11:46 AM, Joseph Gwinn wrote:
In ,
wrote:

On Sat, 30 Jun 2012 13:53:45 -0700, wrote:

On Fri, 29 Jun 2012 22:40:23 -0400, Joseph Gwinn
wrote:

[...]

The best for gluing steel to brass (which I do most often) is
Household Goop.

I'm pretty sure it's a chemistry issue. For such things, one asks
the
glue manufacturer. If I recall, brass is the problem.


The glue manufacturers I asked did not have a dicky. Indeed brass is
the problem. It does not matter how you pre-treat it. Incantations
and
saying Lord' prayer backwards does not work either.

Just Goop.

Michael Koblic,
Campbell River, BC
You saying BRASS is difficult to solder?????

No, glue. I think the zinc reacts badly with some kinds of adhesives.
Aluminum has this problem too. Anyway, there are glues that work, and
glues that don't work.

Joe Gwinn


There are techniques that work as well, not just adhesives.

For instance, for aluminum...
The problem is that aluminum grows an oxide layer is just a few
seconds.
So what you have to do is prep the oxide layer and bond to that.
Phosphate wash followed by two-part primer like EpiBond or Randoplate.
Now your glue can bond to the primer and get some adhesion.

Urethane glues will actually work with the primer, Looks like it
dissolves into the primer.

But for general bonding metal to metal, pick a Goop, any Goop,
and stick with it.

How does this work for people to metal?

Cyanoacrylate. Glues people to almost anything.

Had a case of that yesterday over at Kern Medical Center. Woman went
into the rest room, dropped trou..and parked her ass on the
seat.....which someone had doped nicely with super glue.

She sat there for some time..then tried to get up...after some further
time..she started screaming for help. It was even further before anyone
heard her. Fire department came..tried various things..nothing
worked..seems the lady was a bit obese..and they were having trouble
getting solvent into that lard/seat interface..so they ultimately
unbolted the seat, flipped her on her face..put her on a gurney and took
her down to the ER..where evidently they got the seat off..some 4 hours
later.

Reported on the local news..to great snickers and hands over mouth.

VBG

Gunner


Here's another Gunner confabulated story. This incident happened in a
Wallmart in Monticello, Kentucky, nowhere near Kern County CA. Google it,
there are thousands of hits. Funny that none of these I found mention the
particular details of unbolting the seat and flipping her over. These were
made up for purposes of good story telling I presume?

The specialty rods marketed for repairing and/or joining aluminum parts will
also work well with most non-ferrous metals.. which would include joining
aluminum to many other alloys.

One can expect considerably more joint strength when using the aluminum
repair rods, than the strength from using lead-type soft solder.

When the workpiece(s) can tolerate the higher sustained temperature of about
750 degrees F to join them, the aluminum repair rod will typically yield
very strong joints.

--
WB
..........


wrote in message
...
On Fri, 29 Jun 2012 19:15:13 -0700 (PDT), George Herold
wrote:

On Jun 29, 3:47 pm, Stanley Schaefer wrote:
On Jun 29, 6:48 am, George Herold wrote:

(reposted from SED)
I want to try soldering some aluminum plate (0.032") onto each side
of
a brass cylinder. When trying to solder aluminum in the past I
failed. I think I heard that some Al alloys are easier to solder
than
others. I've got a choice (From McMaster-C) of 6061, 2024. 7075, and
1100. Any idea of which is better?

I was also planning on getting some aluminum flux and some Zn/tin
solder from McM-C. Other suggestions welcome.

Thanks

George H.

It IS possible, but you have to use something to scratch through the
oxide coat first to bare aluminum. Usual practice is to puddle the
solder on the aluminum and use a stainless brush through the molten
solder until the surface is tinned, then sweat the other piece to it.

Yeah, I figured I'd tin both sides and then mash 'em together..
(not sure exactly how to do the mashing, from center out at least.)

I never thought (or heard) of brushing it while under the solder,
Thanks!
My Alcoa book suggests that the high zinc-content solders work the
best, another one recommends almost pure tin, go figure. Fluxes
usually have some really active content to dissolve the aluminum oxide
and will result in severe corrosion if not removed/neutralized.

Yeah.. been there with some SS fluxes. Should be fine if I can tin it
all nicely.


If there's significant stress and it's a butt joint, you may have
cracking and joint failure. In that case you might need some
redesign, like going to solder tabs on your plates and maybe a thin
aluminum shrink-fit tube over your brass to solder to.

Well if solder doesn't work, then maybe some Al 'loaded' epoxy will,
'be the ticket'.


Stan

Thanks again Stan,

George H.
Greetings George,
What Stan says about scratching the surface through the solder is
right on. You can solder without any flux at all. I have used the
aluminum solders available at the hardware store and the strength is
remarkable. You can buy little stainless brushes that are about the
size of a toothbrush at the hardware store too. Once the surface is
tinned it is easy to solder to anything else. If it was me I would
avoid the use of flux on the aluminum just for ease of cleaning. Once
the solder is molten and you start scratching the aluminum through the
solder you will see that the solder will follow the brush as the
brush moves beyond the area initially covered with solder.
Eric

On Mon, 2 Jul 2012 17:27:22 -0700, "anorton"
wrote:


"Gunner Asch" wrote in message
.. .
On Sun, 01 Jul 2012 23:19:48 -0500, Richard
wrote:

On 7/1/2012 3:00 PM, Joseph Gwinn wrote:
In articleoemdndDN_PfxDm3SnZ2dnUVZ_vudnZ2d@earthlink .com,
wrote:

On 7/1/2012 11:46 AM, Joseph Gwinn wrote:
In ,
wrote:

On Sat, 30 Jun 2012 13:53:45 -0700, wrote:

On Fri, 29 Jun 2012 22:40:23 -0400, Joseph Gwinn
wrote:

[...]

The best for gluing steel to brass (which I do most often) is
Household Goop.

I'm pretty sure it's a chemistry issue. For such things, one asks
the
glue manufacturer. If I recall, brass is the problem.


The glue manufacturers I asked did not have a dicky. Indeed brass is
the problem. It does not matter how you pre-treat it. Incantations
and
saying Lord' prayer backwards does not work either.

Just Goop.

Michael Koblic,
Campbell River, BC
You saying BRASS is difficult to solder?????

No, glue. I think the zinc reacts badly with some kinds of adhesives.
Aluminum has this problem too. Anyway, there are glues that work, and
glues that don't work.

Joe Gwinn


There are techniques that work as well, not just adhesives.

For instance, for aluminum...
The problem is that aluminum grows an oxide layer is just a few
seconds.
So what you have to do is prep the oxide layer and bond to that.
Phosphate wash followed by two-part primer like EpiBond or Randoplate.
Now your glue can bond to the primer and get some adhesion.

Urethane glues will actually work with the primer, Looks like it
dissolves into the primer.

But for general bonding metal to metal, pick a Goop, any Goop,
and stick with it.

How does this work for people to metal?

Cyanoacrylate. Glues people to almost anything.

Had a case of that yesterday over at Kern Medical Center. Woman went
into the rest room, dropped trou..and parked her ass on the
seat.....which someone had doped nicely with super glue.

She sat there for some time..then tried to get up...after some further
time..she started screaming for help. It was even further before anyone
heard her. Fire department came..tried various things..nothing
worked..seems the lady was a bit obese..and they were having trouble
getting solvent into that lard/seat interface..so they ultimately
unbolted the seat, flipped her on her face..put her on a gurney and took
her down to the ER..where evidently they got the seat off..some 4 hours
later.

Reported on the local news..to great snickers and hands over mouth.

VBG

Gunner


Here's another Gunner confabulated story. This incident happened in a
Wallmart in Monticello, Kentucky, nowhere near Kern County CA. Google it,
there are thousands of hits. Funny that none of these I found mention the
particular details of unbolting the seat and flipping her over. These were
made up for purposes of good story telling I presume?


If I remember correctly, the first time I heard that story the ass on
the throne was the NCOIC of the Missile Assembly Shop at Udorn RTAFB,
Thailand in about 1971-2. The other details have remained almost
exactly the same though.

An urban myth perpetrated down through the ages :-)

On 7/3/2012 1:53 PM, Gunner Asch wrote:
....

But it appears to be a very dirty trick that has managed to survive to
be occasionally played on the helpless.
....

I keep wondering about the "how?", though...generally a super glue
(2-methyl cyanoacrylate) has a setup time measured in a few seconds or a
minute or so on the outside. It seems fairly unlikely to me the time
between stall occupancies would be so short as to there to be a large
enough amount still active as to cause such wholesale adhesion and/or if
there were such a large amount in place it wouldn't have been noticed...

Just seems totally strange to me...and the the same story was reported
on local news here as well.

--

On Tue, 03 Jul 2012 14:09:15 -0500, dpb wrote:

On 7/3/2012 1:53 PM, Gunner Asch wrote:
...

But it appears to be a very dirty trick that has managed to survive to
be occasionally played on the helpless.
...

I keep wondering about the "how?", though...generally a super glue
(2-methyl cyanoacrylate) has a setup time measured in a few seconds or a
minute or so on the outside. It seems fairly unlikely to me the time
between stall occupancies would be so short as to there to be a large
enough amount still active as to cause such wholesale adhesion and/or if
there were such a large amount in place it wouldn't have been noticed...

Just seems totally strange to me...and the the same story was reported
on local news here as well.

Watch for a lawsuit against Wallymart?