Oxy-Acetylene Torch Brazing (video)

[ChuckE2009]

Goodmorning, everyone!!

So... *leans back in chair*

Back in my day, in high school, like three years ago :laughing:

We did a little torch brazing... We made pirate-ships out of like 22 gauge steel, and it was a blast... Actually it WAS a blast, one of my buddies in that class didnt turn his torch off all the way one day, and set it down next to an opening in his boat... Then he started brazing on it a few minites later and it **** near exploded... Ahha, the memories

Where was I going with this, oh yeah, right...

I recently picked up a tube of brazing rods, and the other night my friend Wes (whose been in a number of other videos with me) happened to stop by and we did some Oxy-Acetylene torch brazing, just because.

It wasn't an all out instructional video like I usually do, just some footage of us brazing some 14 gauge steel coupons with commentary on what we're doing and a few tips thrown in there as well. I thought it turned out really well, and people on YouTube seem to like it, so I figured I'd just stop in and share it with y'all real quick. I plan to make more brazing, and some oxy-acetylene videos in the near future.

Hope y'all like the video:

Have a great week, everyone!

 

[Arc weld]

A few things I noticed in this video. Electrodes are for arc welding. A lot of brazing rods are called bronze when they're actually more brass than bronze. Not sure why. Although not as critical as gas welding, it's a good idea to balance your gas pressures. The best way is use your regulators and not even worry what the gauges say. Brazing is opening the pores in the base metal as opposed to fusion welding where you're melting the base metal. If you get a lot of white smoke means you're too hot. The glass like coating is silicon the same as a MIG weld. Silicon is a deoxidizer. It really helps on a lap joint to move the torch in little circles. If your heat is just right you can keep moving in circles along the seam adding lots of brazing rod. Another accepted method(and usually easier) is to add the brazing rod, do a couple little circles and then pull the torch away to let it just solidify/build up and then repeat it down the seam. Properly done you shouldn't see the line where the top plate overlaps the bottom plate and there will be ripples in the bead. The seam should be in the middle of the braze bead. If you're really good, you could have a stack of dimes look. O/A has a big advantage over TIG in that you can easily adjust your heat by just moving the torch further away or closer to the work or just taking it completely away for a second to let the weld/braze cool or solidify.

Try going in circles and see what your results are. A brazed joint will be wider than a welded joint but should be uniform width down the seam. Brazing is great for thin and small things that would be impossible to weld. The electric shut off solenoid on my diesel welder went kaput so I just brazed a connecter on the arm so I could use a common choke cable to shut it off. I didn't need to spend $126 just so it would shut off with the key.

 

[Mark @ Everlast]

Good video.

A few tips: Match the tip size with the pressure for both oxy and acetylene. They should be balanced for both. Something like a 00 tip should use 2 lbs or so minimum. You can get a stack of dimes look. For something that thin, the flame needs to go a little lower.
Don't force the flame to melt the rod, but let the heat of the metal do it.
Next time use the bare rod and a can of flux. It's more economical.

When I was in school we did bend tests on 1/4"...hammered them back flat and bent them the other way.

 

[Arc weld]

I think we used to bend them and the braze shouldn't pull apart at the overlap.

The best way to balance a torch is to start with the regulators completely off. Turn the acetylene on just enough so you can light it, then open the acetylene valve on the torch all the way open. Now slowly turn the regulator up until the flame is just starting to jump from the end of the tip. This tells you the maximum flow that particular tip can use. Next, turn down the acetylene a little with the torch valve so oxygen can be added without blowing the flame out. Now with the oxygen valve on the torch fully open, slowly turn the regulator in to add oxygen to the flame. Now that some oxygen has been added, turn the acetylene valve on the torch fully open again. Keep slowly turning the oxygen regulator in until you get a neutral flame. Both torch valves should be fully open. The torch may be balanced now but the way to check is to turn the acetylene regulator in a tiny bit more and see if the flame changes. If it doesn't, your torch is balanced. If the flame changes, turn the oxygen regulator in slightly till you again get a neutral flame. Sometimes you have to do this last test a couple times but it is the most accurate way to balance any size of torch tip. Don't worry at all what the pressures read on the regulators. The tip is telling you what it can handle. It sounds kind of involved but once you do it, it's pretty simple.

 

[Car Doc]

Yeah good video you did good explaining it! I am lazy I rarely even put a welding tip on my torch any more. I got to where I can do a pretty decent braze job with the cutting tip on a quicky weld its not economical but it works just a matter of managing the heat and rod.

 

[Furu]

While arc welding is relatively new to me, I have done O/A for quite a while. Where I have used brazing most and recently did quite a bit of, is in hydraulic tube fittings. Brazing on fittings is very economical and requires not much more than silver braze, flux, and a torch. There are commercially made braze rings available, made by a few companies but not economical or necessary. Easy to make repairs to tubing as well. To get adequate joints however it is necessary to use a silver braze. Both black and white flux work but I prefer black flux on smaller tubing and white flux on larger tubing. As Mark pointed out use flux and bare rod it is much more economical than that coated stuff. Easier to control as well.

 

[Arc weld]

I think you're comparing silver soldering to brazing. While silver solder is a type of brazing, it is different from brazing like in the video.

 

[Furu]

Actually I am not talking/writing about silver soldering.

You use that for plumbing and do it with a propane torch when dealing with potable water systems. I am talking about silver alloy brazing, about 41-56% silver not the plumbing stuff at all. I like 56%. Propane could not touch it unless you combined propane with oxygen in your torch. Never tried it always used acetylene.

If you used silver solder on a 3000-6000psi hydraulic hardline steel or stainless steel tube you would find not only would it fail but if you were hit by the ensuing leak you might keep the limb if you made it to an emergency room within 15-30 minutes, maybe. Hydraulics are not to be trifled with. And there is a huge difference between silver braze and silver solder and melting points etc.

I have included a couple of links below for review if interested in learning about it. There is a lot more that I did not try to link to as much of the info is in large volumes.

It is also used for joining metals together much like in the video but in more specialized circumstances.

Understanding Brazing Fundamentals
http://www.parker.com/literature/Literature Files/tfd/bulletinpdf/braze.pdf
Silver Brazing vs Silver Soldering | Carbide Processors - YouTube

As is pointed out in the video; terminology is often misused to the detriment of the uninformed user.

 

[Arc weld]

Silver brazing and silver soldering are often used interchangeably just like he said in the video. Silver soldering is sometimes called high temperature brazing as well. Regardless of what it is called, it is not the same as soldering used for plumbing or brazing using brass or bronze filler metal. The OP's video did not use silver based filler metal. Brazing or soldering using silver based filler metal usually relies on capillary action to pull the filler metal into and around the joint, the same as plumbing solder. You get a nice clean joint without much build up. Brazing with brass usually has a lot more build up and doesn't leave nearly as nice a finished joint. Using brass/bronze you can also build it up and fill big holes, kind of like aluminum TIG welding. It's even been used for building up gear teeth and if built up enough, used to successfully repair steel hydraulic lines.

 

[Willl]

You guys all fancy... real braze rod is coathanger.