Brazing capacity of Bernzomatic Oxy/Mapp torch?

Jon, I had one of those little torches for awhile. They are not too bad but go through the gas really fast. They will braze pretty well for stuff that size but I think you ar going to have trouble brazing carbide to brass. The brass and brazing rod melt at the same temp. I would go with a good mapp torch without the O2 and silversolder.
Glenn

"Glenn" wrote: I would go with a good mapp torch without the O2 and silversolder. ^^^^^^^^^^^^^^^^^ I was going to suggest Mapp gas WITH O2 and silver solder.

Thanks, Glenn. I am actually planning on using a brazing ribbon, with a liquidus of 1305F (707C), which should give me a little more room to work with than a rod.
Jon.

I never had any luck at all silver soldering or brazing using any kind of Bernzomatic anything. However, with an oxy/acetylene rig it works fine for me. My general comment is sure, try it, but if it doesn't work right away and quickly, then don't waste your time and expensive little bottles, just go rent an O/A setup and be done with it.
GWE

I have an oxy/acet torch, but would not bother to uncoil the hose for your job. That is if I understand correctly. The ringer is how long is that brass rod.
If it is 6 inches long or less, I would use one or two plain propane torches and stack a couple of insulating fire brick to support the work and keep the heat from radiating away. Plain propane is plenty hot enough for silver brazing.
If that brass rod is long, then it is easier to supply a lot of heat in a hurry and get it brazed without getting the whole rod hot.
Even though you already have the oxy/mapp torch, I would use a plain propane torch to preheat the brass. Just because it is less expensive.
Dan

as something of an advanced hobby machinist..I question the utility of using carbide bonded with brass as any sort of cutting tool, for anything other than a hand scraper.
Gunner
"A prudent man foresees the difficulties ahead and prepares for them; the simpleton goes blindly on and suffers the consequences." - Proverbs 22:3

I've done some - but as said before - runs a lot of Oxygen tanks and the are expensive.
You might have better luck by pre-heating in a furnace or oven and then place it in a insulative area when trying to braze it. E.G. use the oven to get the Heat content up to temperature and use the torch to push it over the top for the braze with a little more humph.
What I did was to get a O/A gauge set and hoses and then a tank of Oxygen and use my 30 gallon of Propane as the fuel. Got the propane torch for the Vector set. Works nice.
Martin
Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder
Grant Erw>

Thanks, Dan, that sounds like a worthwhile plan to me. I'll get the bar as hot as I can with the propane, and then use the oxy/mapp to heat the tip for the actual brazing.
Jon

If it is an insert it has almost certainly not been braze treated.
I would lighlyt grind the contact area of the insert and the contact area of the rod in a bench grinder or with a dremel tool using a stone.
For fixturing I would suggest a fire brick with 1 =BD" hole in from the the bottom half way and a 2" hole in for the top half way. Insert the rod from the bottom. Dip the trimetal braze alloy in Black Flux. Use Black Flux because you will need the extra Boron for an extended heating cycle.
Put the trimetal braze alloy on the rod and put the insert on top of that. Heat through the carbide which will which will help compensate for the differences in thermal expansion. =20
Tom

If it is an insert it has almost certainly not been braze treated.
I would lighlyt grind the contact area of the insert and the contact area of the rod in a bench grinder or with a dremel tool using a stone.
For fixturing I would suggest a fire brick with 1 ½" hole in from the the bottom half way and a 2" hole in for the top half way. Insert the rod from the bottom. Dip the trimetal braze alloy in Black Flux. Use Black Flux because you will need the extra Boron for an extended heating cycle.
Put the trimetal braze alloy on the rod and put the insert on top of that. Heat through the carbide which will which will help compensate for the differences in thermal expansion.
Tom
Thanks, Tom. All I have available locally here is regular silver solder flux, so I'll be using that. Thanks for the sandwich and heating technique suggestions, though, that is something I hadn't figured out how to accomplish yet.
Jon

If by regular flux, you mean white flux then use a lot of it.