I'm attempted to do some brazing, never done it before, although I have
soldered some copper pipes before!

I have a piece of 1/4" plate with a hole drilled in it, I have a piece
of 3/4" black iron pipe threaded into a 3/4" ell (elbow?). This pipe will
pass through the hole in the plate and needs to be brazed to seal it up. I
need it to be leak free.

To get some practice, I tried to see if I could braze the threaded pipe
to the 3/4" ell (elbow?), I cleaned the pipe threads and the ell with
acetone and I screwed the pipe into the ell. I got out my small propane
cylinder with a hand held torch tip. I heated the part till it was a light
colored red and try as I may, could not get the brazing rod to flow
worth a dam. Figured I wasn't getting enough heat, so I got out my #20
cylinder of propane and my torch head from my aluminum melting furnace. I
fired it up and blasted the pipe fitting for quite sometime. The brazing
rod was getting soft and would melt, but in globs and would not stick to
the pipe fittings.

Any tips, comments, suggestions?

This is all the equipment I have, no O/A torch kit, don't know nobody
who has one and don't want to pay someone to do this for me. I want to
learn how to do it.

Thanks.




--
A7N8X-Deluxe, AMD XP2500+ (Un-locked)
2x256mb Crucial PC3200 DDR ram
Palit-Daytona Ti4200/64M AGP

The small torch you describe isn't hot enough to do an adequate job.
You really need oxy-acetylene to braze larger objects.
Also need to use a brazing flux to make the brass flow. Common
household Borax will do in a pinch. Heat the end of the rod and dip it
in the flux before brazing.
It is a pretty simple technique; the same as soldering except with a
higher temperature.
Good luck, Bugs

In article , SomeBody says...

acetone and I screwed the pipe into the ell. I got out my small propane
cylinder with a hand held torch tip.

Too small, not enough heat. Get an O/A rig to do this job.

Jim


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please reply to:
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==================================================

SomeBody wrote:

I'm attempted to do some brazing, never done it before, although I have
soldered some copper pipes before!

I have a piece of 1/4" plate with a hole drilled in it, I have a piece
of 3/4" black iron pipe threaded into a 3/4" ell (elbow?). This pipe will
pass through the hole in the plate and needs to be brazed to seal it up. I
need it to be leak free.

To get some practice, I tried to see if I could braze the threaded pipe
to the 3/4" ell (elbow?), I cleaned the pipe threads and the ell with
acetone and I screwed the pipe into the ell. I got out my small propane
cylinder with a hand held torch tip. I heated the part till it was a light
colored red and try as I may, could not get the brazing rod to flow
worth a dam. Figured I wasn't getting enough heat, so I got out my #20
cylinder of propane and my torch head from my aluminum melting furnace. I
fired it up and blasted the pipe fitting for quite sometime. The brazing
rod was getting soft and would melt, but in globs and would not stick to
the pipe fittings.

Any tips, comments, suggestions?

This is all the equipment I have, no O/A torch kit, don't know nobody
who has one and don't want to pay someone to do this for me. I want to
learn how to do it.

All surfaces to be brazed need to be ground or sanded to bare metal.
Must be clean! No oil or scale. Also flux must be used. Mix a little
powdered flux in water to a thick paste and apply with a small brush
where you want your brazing metal to adhere. Thirdly, I don't think
your torch is hot enough. I always oxy-acetylene for brazing, never had
luck with propane.

Gary Brady
Austin, TX

Thirdly, I don't think your torch is hot enough.

I have managed to silver solder tiny parts with a turbo torch.
It took two propane torches to do a part about 1 inch square.

Silver solder melts around 1200F and I think brazing is even
higher.

It can be done, but you need to figure out how to insulate the work so
you can get the work a little hotter.

You need to have every thing clean and use flux. With propane it will
take longer to get hot enough, this means more time for the work to
oxidize. To counter that you need more flux.

You are at the limit of doing it. If you have access to a ceramics
kiln, you might try that. If you have access to a welder, you might
try using a carbon arc to heat things.

Dan

Tom

Propane gets hot enough but it doesn't deliver nearly as much energy
as acetylene does.

Brazing is soldering but at higher temperatures.

Can you get by with a soldered joint ?

Try cleaning the area with a strong caustic such as Easy Off oven
cleaner to remove oils and greases.

You need to get all three parts (the two parts to be joined and the
braze alloy) hot enough at the same time.

Theoretically you can use propane because it gets hot enough. However
it delivers the energy so slowly that you lose a great deal.
(Theoretically you can move the same load in a pick up truck that you
can in a semi. You just make more trips.) You could get fire bricks
and try to make a little oven type set up to trap some heat.

Mostly I'll go with the other guys and recommend an oxy acetylene
torch. There are an awful lot of these around. If you were to ask
enough folks I'm sure someone would know of one.

Tom

SomeBody writes:

Any tips, comments, suggestions?

Propane will work up to a point.

I've done some larger pieces with the added heat of a Reil burner like you
describe. You're probably right on the edge of getting it to a high enough
temperature. Try clamping up the big Reil burner to heat the piece
overall, and then apply the biggest hand-helf torch (e.g., Turbotorch, yes,
a 2nd torch) you can find to the joint.

Also make sure you are using a low-temp alloy brazing rod.

Get a jar of some good commercial brazing flux. It will work better and
easier than improvising with borax and such.

On Tue, 11 Oct 2005 12:42:37 +0000, Gary Brady wrote:


Would things improve if I used MAPP gas instead of propane?
I hadn't thought about the scale on the plate? Will grind it down to bare
metal and look for a lower melting rod, instead of the bronze(?) rod I
bought. I do have some insulating kiln bricks that I could make a small
furnace to heat the items. I will used my "Monster" Reil type burner to
heat the items.

Great info and advice, thanks.


SomeBody wrote:

[quoted text muted]

All surfaces to be brazed need to be ground or sanded to bare metal.
Must be clean! No oil or scale. Also flux must be used. Mix a little
powdered flux in water to a thick paste and apply with a small brush
where you want your brazing metal to adhere. Thirdly, I don't think
your torch is hot enough. I always oxy-acetylene for brazing, never had
luck with propane.

Gary Brady
Austin, TX



--
A7N8X-Deluxe, AMD XP2500+ (Un-locked)
2x256mb Crucial PC3200 DDR ram
Palit-Daytona Ti4200/64M AGP

On Tue, 11 Oct 2005 08:56:49 GMT, SomeBody
wrote:

I'm attempted to do some brazing, never done it before, although I have
soldered some copper pipes before!

I have a piece of 1/4" plate with a hole drilled in it, I have a piece
of 3/4" black iron pipe threaded into a 3/4" ell (elbow?). This pipe will
pass through the hole in the plate and needs to be brazed to seal it up. I
need it to be leak free.

To get some practice, I tried to see if I could braze the threaded pipe
to the 3/4" ell (elbow?), I cleaned the pipe threads and the ell with
acetone and I screwed the pipe into the ell. I got out my small propane
cylinder with a hand held torch tip. I heated the part till it was a light
colored red and try as I may, could not get the brazing rod to flow
worth a dam. Figured I wasn't getting enough heat, so I got out my #20
cylinder of propane and my torch head from my aluminum melting furnace. I
fired it up and blasted the pipe fitting for quite sometime. The brazing
rod was getting soft and would melt, but in globs and would not stick to
the pipe fittings.

Any tips, comments, suggestions?

This is all the equipment I have, no O/A torch kit, don't know nobody
who has one and don't want to pay someone to do this for me. I want to
learn how to do it.

Thanks.

Ron Reil wrote of brazing two cannon balls together with his propane
burner, and people use them to melt brass, so brazing is definitely
possible with your propane burner.

You need to contain the heat. Try making an enclosure out of fire
bricks, or perhaps heating the work in your aluminum melting furnace.
Brazing is done at temps somewhat higher than needed to melt aluminum,
typically about 1600 deg F. Light red isn't hot enough, gotta be
orange. Alloys containing silver work at lower temps (1200 or so,
dull red) but are more expensive. You might have better luck with a
silver-brazing material.

The problem isn't so much propane vs acetylene as it is air/fuel
rather than oxy/fuel . Air is only about 20% oxygen. Your burner
needs to flow a lot of air to burn the propane, and that airflow cools
both the flame and the work. Oxy/propane works well for brazing
but requires an oxy/fuel torch.

As thte others have said, you're not getting hot enough and you need to use
flux.
Borax is thte flux to use and you can use any borax supply for this. I've
used 20 Mule Team brand borax as a cheap source and it works well.
For more heat with your equipment, use MAPP gass rather than propane. An
O/A torch works better but if you don't have one, the MSPP gas will work.
Brazing is a version of soldering and all of the soldering rules apply.

--
Why do penguins walk so far to get to their nesting grounds?

If you want to call we will send you a jar of Black Flux free and some
braze alloy. Call Tom or Emily at 800 346-8274. We usually sell
this in large lots instead of giving it away but I like your attitude.
It's people who won't quit that make a better world.

flux info
http://www.carbideprocessors.com/Brazing/book/13.htm

Braze alloy info
http://www.carbideprocessors.com/Brazing/book/12.htm

Sand or grind the material down to a rough / gray (smoetimes called '
white' metal) and use a lot of flux. When you are through you still
want to see some Black Flux left.

cleaning
http://www.carbideprocessors.com/Brazing/book/11.htm

For a temperature / color chart go to
http://www.carbideprocessors.com/Brazing/book/15.htm

This is steel under lab conditions and it is just the surface. You
want to heat the part all the way through so you will need to get it
hotter.

tom

I just found this. It is about carbide but the basics are the same.


Brazing Tungsten Carbide for the First Time

The surface condition of tungsten carbide can make the difference
between parts that are joined with a strength of 100,000 psi. and parts
that fall off by themselves. You need to make sure the surface is
clean and ready for brazing. The best way to determine this is to use
a tungsten carbide supplier that can tell you about the surface
condition of your parts. Often good tungsten carbide comes ready to
braze from the manufacturer. If the parts do not adhere well see the
chapter on cleanliness and surface treatment.

Do not get the tungsten carbide oily or greasy. Make sure the steel is
clean also. Do not heat either part without a protective flux coating.

Flux
Braze alloy joins to metal. Metal oxidizes faster if it is hot. If
you heat metal without flux you will form an oxide layer that is
similar to rust. Brazing over oxide is like painting over rust.
Rarely doe anyone get in trouble using too much flux.

Braze alloy
There are many choices. The safest to use is a pretinned tip or
trimetal also called plymetal or sandwich. It comes as ribbon. It is
flat and has unique properties that relieve stress caused by
overheating. It is a tremendous aid when heating large parts or
working with a torch. It is more expensive than wire. If you are
starting and doing just a few parts this is safer and probably easier.
0.15" (15 thousandths) is about as thick a ribbon as you will need.

Prepare a clean piece of steel. Make sure there are no oils or
greases. Alcohol and detergent or soap may both be necessary. Easy
Off Oven Cleaner works very well but is dangerous. Remember steel
comes oiled to keep it from rusting. An oil layer you cannot see or
feel can ruin a braze joint.

Coat the steel with a layer of Black Flux. (Black flux has more Boron
than White Flux and works longer at higher temperatures.)

Put down your piece of braze alloy cut to shape and coat with a light
layer of flux.

Put the clean tungsten carbide on top of the flux layer and coat the
outside with a thick layer of flux.

Hold the part in place with a ceramic rod while brazing.

Heat the whole part as evenly as possible until the whole joint is at
the proper temperature. This is usually at least a dark cherry red.
Remember that the part has to be hot enough all the way through. This
can be a problem even on the parts as small as saw tips.

Once the parts are hot enough you will see the alloy flow out of the
joint. You may also feel the part move just a bit as the alloy turns
liquid. Once the part is the right color (dark cherry red to cherry
red) and the alloy is coming out just a bit (and it may feel mushy),
then wiggle the part just a little bit to allow any flux or fumes to
escape. If you work the part too hard you can force all the braze
alloy out of the joint and ruin it.

The flux cleans off with warm water. You can use mild brushing if you
wish to speed the process.

I called and talked with Tom, great guy, very helpful.
Tom had sent the package with a #1 can of "Black Flux" and some brazing
wire. He even tossed in a really nice coffee mug filled with candy, Nice
touch!

I haven't begun to do the brazing project yet, got a hurricane heading
my way and need to prepare for the worse. Need to finish up on the
modification to my 10Kw generator project, converting from a evap cooling
to a thermocooling system.

Thanks Tom.


On Wed, 12 Oct 2005 08:06:10
-0700, president wrote:


snip..snip


This is steel under lab conditions and it is just the surface. You
want to heat the part all the way through so you will need to get it
hotter.

tom

--
A7N8X-Deluxe, AMD XP2500+ (Un-locked)
2x256mb Crucial PC3200 DDR ram
Palit-Daytona Ti4200/64M AGP