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Atmospheric Propane Brazing Torch Experiments

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vtsteam:
It's really clear to me that we have enough heat and a high enough temperature to easily braze with, but that heat is scattered over a very large flame. As a result it cannot raise a local temperature high enough to melt brazing rod.

One way of concentrating and collecting that heat in a small space is by enclosing it. Thus a brazing hearth.

Here's a very simple hearth I put together to test this method with the new torch. A few pieces of used insulated firebrick stacked together.

vtsteam:
Success!

vtsteam:



Not a pretty job, but it was just a couple of bandsaw cutoffs laid on top of each other, and had they had been subjected to many previous tests, thus the heavy oxide layer.

It may be that my torch has an excess of oxygen however, which is easy to control with a choke. Early on it had an oxygen deficit and the first flames had a bit of orange in the feather. I was considering opening up the slots or adding another. However, repositioning the gas orifice and adding flare to the flare made this unnecessary.

vtsteam:
I have 4 hand held canister gas torches -- 2 older propane versions and 2 Mapp types. All 4 have an insert located an inch or two from the tip. As a guess they act as flame holders, as mixers, and as flow straighteners to keep the flame size compact. That's a guess.

The older propane torches inserts are shaped as a single larger orifice in the center, and a series of smaller orifices in a ring at the edge of the disk shaped piece. The tip of the torch is not flared on one tip (Bernzomatic brand), and there is a flare in back of the tip on the other (Weller brand)

The mapp gas torches (Bernzomatic) have a newer style "swirl" insert which consists of 4 angled vanes. The tip of the torch has a reverse flare (constriction).

I think I will try to make some inserts for my shop made torch to see if I can reduce and concentrate the flame.

NeoTech:
Ah slide restrictor for the burner could prob. improve it further dont you think? =)

I found your hook up for the burner very refreshing anyway.. not that many parts needed. =)

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