In my jewelry work, I use a number of torches, ranging from
cigarette-lighter-based inexpensive butane ones to oxy-propane
and oxy-acetylene. Here are a few things I've found:

1. The fuel/air torches (butane, bernz-o-matic, etc) benefit from
having adjustable mixture. I've added an adjustment to my
bernz-o-matic. It's a piece of scap brass sheet about 1" by 1/4"
rolled into a ring. It is slid over the air inlet holes on the torch
to adjust the mixture. The right mixture helps prevent oxidizing the
work.

2. It is difficult to control heat output from the torches directly
attached to disposable propane cylinders. The angle of the torch
affects pressures and fuel flow. The ones with hoses between the
cylinder and torch head have worked better for me.

3. For gold, silver and brass casting on the cheap with up to an
ounce or so, a high-output (not the regular) bernz-o-matic propane
torch with Mapp gas can work OK. But keep the air/fuel mixture a
little rich.



(TrevorF) wrote:

Hello Des;

For smallish projects, such as light chains and slender rings, I've
found the refillable Benzomatic butane torches to be quite
satisfactory. They're easy to find, refillable from normal lighter
canisters and very convenient to use (no hoses, very light, etc).
What they are not is very versatile. I found I had to keep my
projects quite small and uncomplicated in order to have the Benzo
still able to do the job.

In my own work in sterling and 14k yellow gold I quickly found the
Benzo inadequate so I added an equally inexpensive propane plumber's
torch (disposable canister type). With these two you've got a choice
between a moderately hot but small flame or a moderately hot big fat
bushy flame ... and nothing in between, or more or less. That said
they did allow me to make close to a hundred pieces --chains, rings,
pendants, bracelets, earrings-- including broad-banded, bi-metal
wedding rings for my wife and I.

But as things turned out with the Benzo, so too with the plumber's
torch. I found that the more I wanted to diversify my work the more I
found these two torches rather limiting: you can't really cast, you
often can't do complicated designs (unless you don't mind cooking your
entire piece each and every time which means you're constantly
battling serious fire-scale problems) and you have no ability to do
fine work on larger pieces.

You specifically mentioned annealing and casting. I've found the
propane plumber's torch fairly useful for annealing because of that
big bushy flame that's useful for "painting" the heat into wire coils,
plate, rod, etc. Everything has to be covered in a good firescale
protector though. And setting up a three-sided space with firebricks
will help put the heat on the metal instead of loosing most of it to
heating air.

Casting on the other hand has been a bust for me. I've found that
there just isn't enough heat coming out of the plumber's torch to
handle even as much as an ounce of silver. I've heard that others
have had success here but I just found it frustrating.

FWIW I'm now in the process of graduating to a oxy-acetylene/Little
Torch rig and I'm very much looking forward to higher heats, smaller
flames and the ability to do modest casting work. I think the Benzo
and the plumber's torch will still have their uses.

Cheers,
Trevor F