On Sun, 26 Oct 2003 19:29:55 -0800, in rec.crafts.jewelry ilaboo
wrote:


thre is a lIt for the Elma ox-hydrogen torch that consists of boric acid
and potassium hydroxide

am I correct in assumin the potassium hydrogex is used to dry the gfas and
the boric acid to be mixed with wood alcohol so that the temperature of
the flam is decreased and the boric acid deposited acting as a flux?
the reason i am asking is that i have a old oxy-hydrogen torch (googling
not to helpful) no manuals an would like to try getting it working
any info is appreciated

I don't know about the elma torch, as I'm not familier with it. There are two
basic types of oxy/hydrogen torches in general use. One is a traditional torch
using a compressed hydrogen tank and compressed oxygen tank. Those are
generally used without additional hardware, just like an oxy/acetylene torch
would be used, with the mix of hydrogen and oxygen being adjusted to give the
desired flame.

I suspect that you're talking, instead, about the "water" torches, which use
electrolysis of water to produce the oxygen and hydrogen. These generally have
no provision for altering the ratio of oxygen and hydrogen, which would
normally tend to produce a fiercly hot flame. To modify this, most of these
torches imploy a vapor fluxing unit, which bubbles the mixed oxygen and hydrogen
through a solvent mix before it gets to the torch head.

Commonly, this can be Methanol or acetone or another solvent, and it's often
also mixed with boric acid as a fluxing agent to reduce oxidation on the
workpiece, though the most important part of the fluxing unit is just the
solvent, to modify the flame temperatures.. There are several actual mixes
that can be used in the vapor fluxing unit, each giving a different flame
temperature, in order to fine tune the torch to the type of work being done.
All of the "water" torches I've seen state that operation of the torch without a
proper solution in the fluxing unit can/will damage the torch, either due to
excessive flame temperatures damaging the tips, or perhaps by allowing the
possibility of a dangerous flame blowback from the torch tip into the torch.
I'm not sure which is the case. Perhaps both.

Meanwhile, the potassium hydroxide is used within the main body of the torch,
mixed with the water which is broken down by the electric current to produce the
oxygen and hydrogen. It's there as the electrolyte. Without it, current would
not pass through the water, and your torch would not produce fuel and oxygen
gas. The potassium hydroxide needs to only be added when the torch is first set
up, or after the reservoir has been comepletely emptied and cleaned, as it's not
normally used up in the operation of the torch. Only the water level needs to
be topped up as it's used, and distilled or deionized water is normally the best
to use, to avoid excessive build up of other mineral deposits within the torchs

It's possible to buy both the appropriate fluxing solutions for the most
commonly sold brands of these torches, and the premixed electrolyte solution for
first filling the torch.

Somewhere around here I've got the formulas for the recommended different
fluxing solutions for the Krohn fluxed flame torch, which I'd assume would be
the same for other brands. Let me know if you'd like me to dig those up
again...

I'm afraid I don't know the concentration of potassion hydroxide needed for the
electrolyte. Perhaps some other reader can fill that in?

Hope that helps.

Peter Rowe