I need to degrease aluminum parts prior to bonding with epoxy. One
part has relatively thin (0.0625in) slots that the other parts fit
into. The epoxy goes into the slots.

I would prefer to use something that isn't hazardous. Someone
suggested Xylene, for example. I don't want to use stuff like that.
We don't have workers who are trained nor the facilities to manage
anything of that sort.

What are my options? Do any of the Citrus-based products work?
Perhaps in a heated ultrasonic tank?

I guess one concern is that the clearner not leave anything behind
that could harm the aluminum-epoxy-aluminum bond.

Thanks,

-Martin

On Aug 12, 4:09*pm, m wrote:
I need to degrease aluminum parts prior to bonding with epoxy. *One
part has relatively thin (0.0625in) slots that the other parts fit
into. *The epoxy goes into the slots.

I would prefer to use something that isn't hazardous. *Someone
suggested Xylene, for example. *I don't want to use stuff like that.
We don't have workers who are trained nor the facilities to manage
anything of that sort.

What are my options? *Do any of the Citrus-based products work?
Perhaps in a heated ultrasonic tank?

I guess one concern is that the clearner not leave anything behind
that could harm the aluminum-epoxy-aluminum bond.

Thanks,

-Martin

It isn't just degreasing you have to do, to get the maximum strength
bond, you have to remove the oxide layer, too. And that has to be
done with the surface under something, either wet with epoxy or with
solvent. What you need to use to get oil and grease off depends on
what's on there to start with. When doing motor home trim on the
powder-coating line, the pieces used to have to go through a power
washer with a proprietary detergent, motor oil was used on the jigs to
bend them up. Then they had to go through an oven to remove the water.
There's a lot of things that will remove oil and grease, a lot fewer
that don't leave residue. Acetone and methyl-ethyl ketone will do a
job on lightly soiled surfaces, you may have to use a degreaser and
then a solvent wash to remove the degreaser residue, depending on what
the parts are contaiminated with. And a lot depends on what sort of
job you're doing. Is this a hobby project and one off, or is it for a
long run of parts in production? You may have to have fume hoods, a
washing station or other setups to satisfy the OSHA-type folks if it's
an industrial operation. And have to pay attention to MSDS, too.
You're opening yourself up to a LOT of legal liability if you don't
train the workers when using any sort of chemicals.

Stan

m wrote:
I need to degrease aluminum parts prior to bonding with epoxy. One
part has relatively thin (0.0625in) slots that the other parts fit
into. The epoxy goes into the slots.

I would prefer to use something that isn't hazardous. Someone
suggested Xylene, for example. I don't want to use stuff like that.
We don't have workers who are trained nor the facilities to manage
anything of that sort.

What are my options? Do any of the Citrus-based products work?
Perhaps in a heated ultrasonic tank?

I guess one concern is that the clearner not leave anything behind
that could harm the aluminum-epoxy-aluminum bond.

Thanks,

-Martin


If it is clean stock you could use alcohol or acetone. Use a dip tank
and drip rack. Just don't allow that clean aluminum to set for more than
a few minutes prior to bonding. Aluminum oxides form REAL fast. What I
would likely do is use the epoxy as a wetting solution and something
like scotch-brite to roughen the surface prior to the final bonding.

--
Steve W.
Near Cooperstown, New York

Life is not like a box of chocolates
it's more like a jar of jalapenos-
what you do today could burn your ass tomorrow!

m writes:

I would prefer to use something that isn't hazardous.

Dawn and water with a toothbrush works as well as any solvent.

On Tue, 12 Aug 2008 19:08:18 -0500, with neither quill nor qualm,
Richard J Kinch quickly quoth:

m writes:

I would prefer to use something that isn't hazardous.

Dawn and water with a toothbrush works as well as any solvent.

Yuck! Then what do you use on the metal, Doc? titter

--
Pain makes man think. Thought makes man wise. Wisdom makes life endurable.
-- John Patrick

"Steve W." wrote in message
...
If it is clean stock you could use alcohol or acetone. Use a dip tank and
drip rack. Just don't allow that clean aluminum to set for more than a few
minutes prior to bonding. Aluminum oxides form REAL fast. What I would
likely do is use the epoxy as a wetting solution and something like
scotch-brite to roughen the surface prior to the final bonding.

When I tried to degrease various sheets of metal to pass the water test
(water runs of in a sheet, does not bead up) I found that acetone by itself
never did a complete job. Usually I had to do a 2-stage procedu Acetone
first, then Zep Industrial Strength Cleaner (that has 2-butoxyethanol, same
as many other cleaners and degreasers including Simple Green, and sodium
silicates). This would pass the test no problem.

However, the cleaner the stuff gets the quicker it oxydizes - sometimes in
front of your very eyes.

There is something about doing the final wash in tap water: It seems to
promote oxydation. I managed to avoid it to some extent by doing the final
washes in distilled water. At least that is my personal impression. I have
not found any literature reference to this phenomenon.

--
Michael Koblic,
Campbell River, BC

Is this a hobby project and one off, or is it for a
long run of parts in production? *You may have to have fume hoods, a
washing station or other setups to satisfy the OSHA-type folks if it's
an industrial operation. *And have to pay attention to MSDS, too.
You're opening yourself up to a LOT of legal liability if you don't
train the workers when using any sort of chemicals.

It's for small-scale industrial production...maybe ten assemblies per
month.

I have a feeling that it might be a better idea to have the machine
shop send the parts to an anodizer before we get them. They can deal
with acid washing, etc. I was trying to avoid anodizing for better
thermal conductivity, but the alternative (having to setup a full-
blown chemical operation in a corner somewhere) just isn't going to
happen. My guess is that we can wipe down the anodized parts with de-
natured alcohol just to clean the surface and then proceed with epoxy
bonding and we'll be just fine.

-Martin

"
If it is clean stock you could use alcohol or acetone. Use a dip tank and
drip rack. Just don't allow that clean aluminum to set for more than a few
minutes prior to bonding. Aluminum oxides form REAL fast. What I

Acetone will leave a residue, Iso alcohol will not. They work real well in
conjunction. Acetone first, wait 5 min, then alcohol. Aluminum oxidizes
within seconds, I've been told.

In article , "Michael Koblic" wrote:

There is something about doing the final wash in tap water: It seems to
promote oxydation. I managed to avoid it to some extent by doing the final
washes in distilled water. At least that is my personal impression. I have
not found any literature reference to this phenomenon.

Possibly due to substantial aeration of the water as it comes out of the tap,
vs. minimal aeration of distilled water being poured from a jug.

On Aug 13, 7:42*am, (Doug Miller) wrote:
In article , "Michael Koblic" wrote:
There is something about doing the final wash in tap water: It seems to
promote oxydation. I managed to avoid it to some extent by doing the final
washes in distilled water. At least that is my personal impression. I have
not found any literature reference to this phenomenon.

Possibly due to substantial aeration of the water as it comes out of the tap,
vs. minimal aeration of distilled water being poured from a jug.

Distillation would remove dissolved air. My shop sink faucet has a
hose adapter instead of an aerator and doesn't cause problems.

"Rick Samuel" wrote in message
...
Acetone will leave a residue, Iso alcohol will not.

CLIP

No kidding! For years, I thought acetone left no "evidence" of use... Then
I tried to prep a window that was tinted on the opposite side for a decal
and found this really annoying oily substance all over the window
afterwards.

We use acetone to prep tapers before installation but I'm betting the
combo-approach is better.
--


Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com

V8013-R



** Posted from http://www.teranews.com **

"Joe AutoDrill" wrote in message
...
"Rick Samuel" wrote in message
...
Acetone will leave a residue, Iso alcohol will not.

CLIP

No kidding! For years, I thought acetone left no "evidence" of use...
Then I tried to prep a window that was tinted on the opposite side for a
decal and found this really annoying oily substance all over the window
afterwards.

Now, I wonder why that is. Basic chemistry tells us that acetone should
evaporate completely leaving no residue. Could it be that it is not an
acetone residue at all but residue of such oils and fat that were there
before acetone was applied, dissolved in acetone and the acetone just
evaporated too quickly? The speed of acetone evaporation is noticeable, just
feel the cooling of the area (or the rag) where the acetone was applied.

--
Michael Koblic,
Campbell River, BC

Now, I wonder why that is. Basic chemistry tells us that acetone should
evaporate completely leaving no residue. Could it be that it is not an
acetone residue at all but residue of such oils and fat that were there
before acetone was applied, dissolved in acetone and the acetone just
evaporated too quickly? The speed of acetone evaporation is noticeable,
just feel the cooling of the area (or the rag) where the acetone was
applied.

That was my initial thought... But we tried it on the glass after it was
totally clean (Windex clean anyway) and it still left the same film whether
we used a clean rag or paper towel.

Something in the acetone leaves what looks like an oily film but apparently
it does not affect products mounted onto Jacobs or Morse tapers as once I
load them, they are often close to impossible to unload - and I like it that
way.
--


Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com

V8013-R



** Posted from http://www.teranews.com **

"Joe AutoDrill" wrote in message
...
Now, I wonder why that is. Basic chemistry tells us that acetone should
evaporate completely leaving no residue. Could it be that it is not an
acetone residue at all but residue of such oils and fat that were there
before acetone was applied, dissolved in acetone and the acetone just
evaporated too quickly? The speed of acetone evaporation is noticeable,
just feel the cooling of the area (or the rag) where the acetone was
applied.

That was my initial thought... But we tried it on the glass after it was
totally clean (Windex clean anyway) and it still left the same film
whether we used a clean rag or paper towel.

Something in the acetone leaves what looks like an oily film but
apparently it does not affect products mounted onto Jacobs or Morse tapers
as once I load them, they are often close to impossible to unload - and I
like it that way.

Acetone itself does not leave a film. However, most of the acetone on the
commercial market is recycled from high-volume industrial uses, where it
picks up oil. The recycling can occur at different levels of quality, and
the ordinary stuff usually contains some oil.

I learned this when I worked in a fiberglass shop at Ranger Yachts. We had a
"commercially pure" grade we used for work where there was going to be some
bonding or painting after the cleaning. I don't know how the grades are
differentiated today but you can be sure, or you could be sure back when I
worked at Ranger, that any acetone you buy in a hardware store or from a
general supplier contains some oil.

--
Ed Huntress

Acetone itself does not leave a film. However, most of the acetone on the
commercial market is recycled from high-volume industrial uses, where it
picks up oil. The recycling can occur at different levels of quality, and
the ordinary stuff usually contains some oil.

I learned this when I worked in a fiberglass shop at Ranger Yachts. We had
a "commercially pure" grade we used for work where there was going to be
some bonding or painting after the cleaning. I don't know how the grades
are differentiated today but you can be sure, or you could be sure back
when I worked at Ranger, that any acetone you buy in a hardware store or
from a general supplier contains some oil.

Generally, I buy it a gallon at a time from Home Depot when I go in.

When I'm in a rush and want to pay through the nose for shipping, I use
McMaster.

Thanks for the background. Very useful.
--


Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com

V8013-R



** Posted from http://www.teranews.com **

"m" wrote in message
...
I need to degrease aluminum parts prior to bonding with epoxy. One
part has relatively thin (0.0625in) slots that the other parts fit
into. The epoxy goes into the slots.

I would prefer to use something that isn't hazardous. Someone
suggested Xylene, for example. I don't want to use stuff like that.
We don't have workers who are trained nor the facilities to manage
anything of that sort.

What are my options? Do any of the Citrus-based products work?
Perhaps in a heated ultrasonic tank?

I guess one concern is that the clearner not leave anything behind
that could harm the aluminum-epoxy-aluminum bond.

Thanks,

-Martin

It looks like you got lots of good advice here, but the point that aluminum
forms a weak oxide layer almost immediately is an overriding one for some
applications. It sounds like your application only loads the epoxy in shear,
which is a lot easier than any job that loads it in peel or cleavage.

You won't get a strong bond to aluminum just by cleaning it; but it may be
strong enough. The mechanical bond you get from ordinary roughness of the
material actually is pretty good when the joint is loaded only in shear.
High-performance applications use PAA (phosphoric acid anodizing) to get a
strong mechanical bond; PAA gets a tight grip on the parent metal and it has
lots of surface roughness for mechanical bonding. Someone else mentioned the
scratch-in method, were you sand the aluminum through a wet layer of epoxy.
This can work very well -- roughly the same as PAA -- and the bond, they
tell me, is chemical as well as mechanical. I have some experience with
this, using it to bond yacht hardware, and it's been very reliable for me,
even in cleavage joints. But that doesn't sound practical with slots.

As for cleaning, see my note to Joe regarding the impurity of ordinary
commercial acetone. A pure, oil-free detergent may work as well for your job
and it will solve a lot of safety problems -- but that's only a guess. Be
aware that detergents usually are alkaline and they will attack aluminum.
The result is that you'll have an especially fast development of the oxide
layer, but it doesn't have to degrade your joint, since you'll probably have
only a mechanical bond to begin with -- one that works by cogging the epoxy
against the roughness of the underlying aluminum.

The chemistry of detergents is complex these days, and I wouldn't try to
sort them out on my own. I would call a big epoxy supplier and ask them
about detergents that they've had success with. The perfumes, emollients,
bleaches, and other crap in retail brands of detergents may bite you in the
back. The reason I think they should know is that they use detergents to
remove the amine blush on epoxy layups, and they have to be able to get a
good bond after washing, when putting on the next layer of epoxy/cloth or
whatever. The guys at WEST System have always been very helpful and
accommodating to me.

Good luck.

--
Ed Huntress

You won't get a strong bond to aluminum just by cleaning it; but it may be
strong enough. The mechanical bond you get from ordinary roughness of the
material actually is pretty good when the joint is loaded only in shear.
High-performance applications use PAA (phosphoric acid anodizing) to get a
strong mechanical bond; PAA gets a tight grip on the parent metal and it has
lots of surface roughness for mechanical bonding.

Thanks, this and other posts have been very helpful. I'll research
PAA. Is this a process that most anodizing shops can apply or is it
specialized?

Per my prior post, I am now thinking that I might go for an anodized
finish rather than raw aluminum. This would have the anodizing shop
deal with post-machining/stamping cleanup. We could then simply wipe
the parts clean with alcohol and proceed to bonding. My guess is that
anodizing won't be seriously harmful to thermal conductivity. This is
a heatsink application for electronics.

-M

In article ,
"Michael Koblic" wrote:

"Joe AutoDrill" wrote in message
...
"Rick Samuel" wrote in message
...
Acetone will leave a residue, Iso alcohol will not.

CLIP

No kidding! For years, I thought acetone left no "evidence" of use...
Then I tried to prep a window that was tinted on the opposite side for a
decal and found this really annoying oily substance all over the window
afterwards.

Now, I wonder why that is. Basic chemistry tells us that acetone should
evaporate completely leaving no residue. Could it be that it is not an
acetone residue at all but residue of such oils and fat that were there
before acetone was applied, dissolved in acetone and the acetone just
evaporated too quickly? The speed of acetone evaporation is noticeable, just
feel the cooling of the area (or the rag) where the acetone was applied.

As others have pointed out, ordinary acetone usually comes with oil
already included.

However, a trick I have used over the years is to mix acetone and 91%
isopropyl alcohol about 50-50 by volume.

The effect can be dramatic: Get three containers, one with acetone, one
with alcohol, the third empty. Try cleaning a surface with a paper
towel dipped in the acetone - smears stuff around but doesn't really
remove the stuff from the surface. Then try cleaning a surface with a
different paper towel dipped in the alcohol - no effect. Pour the
alcohol and acetone into the third cup, mixing them thoroughly. With
yet another paper towel, try cleaning the surface -- the stuff is
removed immediately.

Why does this work? The acetone dissolves stuff that alcohol cannot
touch, and then evaporates, leaving the stuff as a fine dust dispersed
in the alcohol. Following up with pure alcohol should get the residual
oil as well.

Joe Gwinn

"m" wrote in message
...
You won't get a strong bond to aluminum just by cleaning it; but it may
be
strong enough. The mechanical bond you get from ordinary roughness of the
material actually is pretty good when the joint is loaded only in shear.
High-performance applications use PAA (phosphoric acid anodizing) to get
a
strong mechanical bond; PAA gets a tight grip on the parent metal and it
has
lots of surface roughness for mechanical bonding.

Thanks, this and other posts have been very helpful. I'll research
PAA. Is this a process that most anodizing shops can apply or is it
specialized?

I've never had it done, but you'll find plenty of shops that offer it. My
understanding is that it's quite common.

If you know who Ted Mooney is (an expert old timer I've come to respect; I
used to write the Finishing column for American Machinist, and I wrote a lot
about adhesive bonding to metal, but it was decades ago), you'll want to see
his brief comments about it:

http://www.finishing.com/4200-4399/4379.shtml

The comments in that thread go a little overboard for your application, but
they will give you some perspective. None of this stuff is new, BTW. I
researched and wrote about PAA roughly 30 years ago.


Per my prior post, I am now thinking that I might go for an anodized
finish rather than raw aluminum. This would have the anodizing shop
deal with post-machining/stamping cleanup. We could then simply wipe
the parts clean with alcohol and proceed to bonding. My guess is that
anodizing won't be seriously harmful to thermal conductivity. This is
a heatsink application for electronics.

I don't know about the insulating properties of standard thicknesses of PAA.
Anodized layers are basically aluminum oxide, which, at that crystalline
level, is considered to be a ceramic. But my vague recollection is that its
thermal conductivity is high relative to other ceramics.

I would be wary of it, if you need really good thermal conductivity. But the
layer of epoxy itself may be much more insulating, making the thermal
insulation of the anodized layer moot. It's not something I've studied.

PAA is very effective and reliable but it may be more than you need. Not
knowing the strength requirement or the specific loading on the joint, I
can't give you any specific advice about it. All I can tell you is that it's
the standard in industry for bonding to aluminum, especially in aircraft.

Note the comments about applying a primer within two hours. That's something
to watch for, but my recollection is that it's only relevant to very
high-performance applications. It may have something to do with the
hygroscopic property of anodizing. The chemistry of this is over my head,
but anodizing of many types, maybe all types, chemically absorbs and binds
water. It's hard to imagine that your bonding job is going to be very
sensitive to this, because the cogging bond is probably all you need.

--
Ed Huntress

"Ed Huntress" fired this volley in
:

Note the comments about applying a primer within two hours. That's
something to watch for, but my recollection is that it's only relevant
to very high-performance applications. It may have something to do
with the hygroscopic property of anodizing. The chemistry of this is
over my head, but anodizing of many types, maybe all types, chemically
absorbs and binds water. It's hard to imagine that your bonding job is
going to be very sensitive to this, because the cogging bond is
probably all you need.


A freshly anodized surface forms the essence of a molecular sieve. There
are tiny, wormhole-like tunnels all through the surface of the oxide
layer. Those that are sized appropriately will entrap water molecules.

It's not exactly hygroscopic in the sense of attracting moisture by
adding to water of crystalization or by dissolution (like salt or sugar
in humid air), but any moisture that arrives is captured mechanically, so
it amounts to the same thing at a practical level.

LLoyd

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 3.70...
"Ed Huntress" fired this volley in
:

Note the comments about applying a primer within two hours. That's
something to watch for, but my recollection is that it's only relevant
to very high-performance applications. It may have something to do
with the hygroscopic property of anodizing. The chemistry of this is
over my head, but anodizing of many types, maybe all types, chemically
absorbs and binds water. It's hard to imagine that your bonding job is
going to be very sensitive to this, because the cogging bond is
probably all you need.


A freshly anodized surface forms the essence of a molecular sieve. There
are tiny, wormhole-like tunnels all through the surface of the oxide
layer. Those that are sized appropriately will entrap water molecules.

It's not exactly hygroscopic in the sense of attracting moisture by
adding to water of crystalization or by dissolution (like salt or sugar
in humid air), but any moisture that arrives is captured mechanically, so
it amounts to the same thing at a practical level.

LLoyd

Aha. Thanks, Lloyd.

--
Ed Huntress

"Ed Huntress" wrote in message
...

Acetone itself does not leave a film. However, most of the acetone on the
commercial market is recycled from high-volume industrial uses, where it
picks up oil. The recycling can occur at different levels of quality, and
the ordinary stuff usually contains some oil.

I learned this when I worked in a fiberglass shop at Ranger Yachts. We had
a "commercially pure" grade we used for work where there was going to be
some bonding or painting after the cleaning. I don't know how the grades
are differentiated today but you can be sure, or you could be sure back
when I worked at Ranger, that any acetone you buy in a hardware store or
from a general supplier contains some oil.

So in theory using a "clean" acetone should avoid this problem. By that I
mean stuff like nail polish remover or medical plaster remover. Having said
that I wonder how clean they really are.

--
Michael Koblic,
Campbell River, BC

"Michael Koblic" wrote in message
...

"Ed Huntress" wrote in message
...

Acetone itself does not leave a film. However, most of the acetone on the
commercial market is recycled from high-volume industrial uses, where it
picks up oil. The recycling can occur at different levels of quality, and
the ordinary stuff usually contains some oil.

I learned this when I worked in a fiberglass shop at Ranger Yachts. We
had a "commercially pure" grade we used for work where there was going to
be some bonding or painting after the cleaning. I don't know how the
grades are differentiated today but you can be sure, or you could be sure
back when I worked at Ranger, that any acetone you buy in a hardware
store or from a general supplier contains some oil.

So in theory using a "clean" acetone should avoid this problem. By that I
mean stuff like nail polish remover or medical plaster remover. Having
said that I wonder how clean they really are.

I don't know what to tell you about obtaining the "commercially pure" grade
that is used, or was used, in commercial fiberglass manufacturing. I really
doubt if nail polish remover qualifies, but I've never tried to buy the
stuff myself.

Uh, actually, I did, once, around 25 years ago. But fortunately I learned
that it's not the right stuff for cleaning the blush off of epoxy before I
bought it. (The right stuff for that is detergent and water.) I'd check
Thomas and similar sources. Again, I've been told by people who should know
that you simply can't buy it in a retail store.

--
Ed Huntress

In article , Michael Koblic
writes

"Ed Huntress" wrote in message
...

Acetone itself does not leave a film. However, most of the acetone on the
commercial market is recycled from high-volume industrial uses, where it
picks up oil. The recycling can occur at different levels of quality, and
the ordinary stuff usually contains some oil.

I learned this when I worked in a fiberglass shop at Ranger Yachts. We had
a "commercially pure" grade we used for work where there was going to be
some bonding or painting after the cleaning. I don't know how the grades
are differentiated today but you can be sure, or you could be sure back
when I worked at Ranger, that any acetone you buy in a hardware store or
from a general supplier contains some oil.

So in theory using a "clean" acetone should avoid this problem. By that I
mean stuff like nail polish remover or medical plaster remover. Having said
that I wonder how clean they really are.

Just looked at a bottle of nail varnish remover; it contains lanolin.

--
Chris Holford

In article , "Ed Huntress" wrote:

"Michael Koblic" wrote in message
...

"Ed Huntress" wrote in message
...

Acetone itself does not leave a film. However, most of the acetone on the
commercial market is recycled from high-volume industrial uses, where it
picks up oil. The recycling can occur at different levels of quality, and
the ordinary stuff usually contains some oil.

I learned this when I worked in a fiberglass shop at Ranger Yachts. We
had a "commercially pure" grade we used for work where there was going to
be some bonding or painting after the cleaning. I don't know how the
grades are differentiated today but you can be sure, or you could be sure
back when I worked at Ranger, that any acetone you buy in a hardware
store or from a general supplier contains some oil.

So in theory using a "clean" acetone should avoid this problem. By that I
mean stuff like nail polish remover or medical plaster remover. Having
said that I wonder how clean they really are.

I don't know what to tell you about obtaining the "commercially pure" grade
that is used, or was used, in commercial fiberglass manufacturing. I really
doubt if nail polish remover qualifies, but I've never tried to buy the
stuff myself.

Uh, actually, I did, once, around 25 years ago. But fortunately I learned
that it's not the right stuff for cleaning the blush off of epoxy before I
bought it. (The right stuff for that is detergent and water.) I'd check
Thomas and similar sources. Again, I've been told by people who should know
that you simply can't buy it in a retail store.

Lots of nail polish remover has stuff put in intentionally. Perfumes,
oils, etc. If you want to buy it as a solvent, get the cheapest generic
grade you can. However, I'm sure it won't be very pure. I've used CVS
house brand stuff, and it seems to me that it left a faint residue.

Doug White

On Aug 13, 5:42*am, (Doug Miller) wrote:
In article , "Michael Koblic" wrote:
There is something about doing the final wash in tap water: It seems to
promote oxydation. I managed to avoid it to some extent by doing the final
washes in distilled water. At least that is my personal impression. I have
not found any literature reference to this phenomenon.

Possibly due to substantial aeration of the water as it comes out of the tap,
vs. minimal aeration of distilled water being poured from a jug.

Unless you're using well water, tap water WILL have some amount of
chlorine in it, chlorine WILL attack aluminum. We had a fancy water
conditioner on both the powdercoating and anodyzing lines. Removed
the calcium and magnesium components of the hard water, too. On some
parts, they wiped them down manually with lacquer thinner before
running them through the line.

I've not had any problems with acetone contaminants and I've been
using it for a loong time for prepping parts for epoxies. If somebody
wants some super-clean stuff, pay through the nose for "reagent"
grade. I'm not a heavy user of the stuff, though, buying by the
barrel may get you something other than buying by the gallon. What I
get is "C.P." grade and usually off the shelf at the hardware store or
borg.

Re anodyzing: This is nothing magical, it produces a film of oxide
with hexagonal holes in it, really SMALL hexagonal holes. Anything
you put in the water will go in those holes, which is how they dye the
stuff. Dyed coatings get sealed afterwards, the holes are purposely
swelled shut. Now, I wouldn't want to use that particular surface to
bond to, particularly as the coating is as brittle as glass. Using
phosphoric acid for anodyzing probably etches the surface more and
phosphates the surface, might give the epoxy a bit better mechanical
grip. You might be able to produce the same surface effect with grit
blasting, though.

Stan

On Tue, 12 Aug 2008 15:09:11 -0700 (PDT), m
wrote:

I need to degrease aluminum parts prior to bonding with epoxy. One
part has relatively thin (0.0625in) slots that the other parts fit
into. The epoxy goes into the slots.

I would prefer to use something that isn't hazardous. Someone
suggested Xylene, for example. I don't want to use stuff like that.
We don't have workers who are trained nor the facilities to manage
anything of that sort.

What are my options? Do any of the Citrus-based products work?
Perhaps in a heated ultrasonic tank?

I guess one concern is that the clearner not leave anything behind
that could harm the aluminum-epoxy-aluminum bond.

Thanks,

-Martin
===========
Very good suggestions in the thread. However depending on how
understanding your wife is, and the size of the parts, try
running some sample parts after cleaning with varsol to remove
the gross oil and chips, through your dishwasher. High alkaline
dishwasher detergent will strip the oil and very lightly etch the
surface. A no-spot addative may also help to remove the water
(sheeting action). Be sure to wear clean gloves when removing
the parts to avoid contamination with skin oil. You may find it
helpful to run an empty cycle before doing this to be sure all
the food oils/fats are removed, and another empty cycle after
cleaning the parts.

If this works you can invest in a dishwasher for the shop.

FWIW -- this worked well on the older computer boards, however I
never tried on the newer surface mount stuff.


Unka' George [George McDuffee]
-------------------------------------------
He that will not apply new remedies,
must expect new evils:
for Time is the greatest innovator: and
if Time, of course, alter things to the worse,
and wisdom and counsel shall not alter them to the better,
what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman.
Essays, "Of Innovations" (1597-1625).

wrote:

Unless you're using well water, tap water WILL have some amount of
chlorine in it, chlorine WILL attack aluminum. We had a fancy water
conditioner on both the powdercoating and anodyzing lines. Removed
the calcium and magnesium components of the hard water, too. On some
parts, they wiped them down manually with lacquer thinner before
running them through the line.


Stan

Stan, What shop did you work in with powder and plating? I spent a few
years in a local place doing powder and plating myself. (W.W. Custom
Clad) They have been run into the ground as of late.

--
Steve W.
Near Cooperstown, New York