I’ve learned so much from reading the posts here and you’ve
encouraged me (without knowing it) to take Metalsmithing I at our
local arts center. In our first class the teacher talked about
various gases for soldering and I asked her about using a torch that
I have in the kitchen for caramelizing creme brulee.
We must have been talking at cross-purposes because she thought I
was talking about butane, but when I got home and looked at the
cannister, it’s propane, about a foot tall and five inches across.
Maybe it’s a plumber’s tool - it was purchased in a hardware store.
I know that some people do solder with propane so I’m curious about
how I might adjust the size of the flame to work with small pieces
of jewelry.
Is there a smaller head that I can purchase to attach to the propane
cannister? What would it be called and where do you think I might
find one if there is?
Since there has been recent discussion about teaching metalsmithing,
I’d like share the projects that we’ll be working on in this 9-week
class:
A pin or pendant made of brass
A ring
Chain
We started out by cleaning and sawing a 2" square of copper sheet
into four “puzzle pieces” and our homework was to come up with a
design for the pin/pendant. I’m going for an Egyptian theme for that
and the ring - I have a customer who wants a ring in an Egyptian
motif.
Is there a smaller head that I can purchase to attach to the
propane cannister? What would it be called and where do you think I
might find one if there is?
You do need one. No matter how big the torch head is, it can be
adjusted to a soft lazy flame. It is a common mistake in learning to
solder. It is not the size of the flame, it is the intensity.
Smaller heads sometime required, but as a beginner you will not
encounter these situation for some time. Learn to adjust your torch
to soft. slow flame, barely hot enough to accomplish the task.
I have an article on my website about torch modification how to
achieve even softer flame than what is available from commercial
torch heads. You may want to read it.
I asked her about using a torch that I have in the kitchen for
caramelizing creme brulee.
We must have been talking at cross-purposes because she thought I
was talking about butane, but when I got home and looked at the
cannister, it's propane, about a foot tall and five inches across.
Creme brulee torches are indeed butane torches, not propane. What
you have is a plumber’s torch. A lot can be done, however, with
butane torches. I purchased a more turbo charged handheld butane
torch from my hardware store, when my supermarket bought creme brulee
torch stopped working. It has coped with some pretty hefty projects -
with difficulty in some cases, but coped nonetheless.
If it is the common plumber/home use torch that is easy to find and
uses disposable tanks, there is a torch with a hose that can attach
to it. I think it then, has different tips. This would be a lot
easier to use than holding the whole tank to use it.
If you use a plumber’s torch you may experience what I think of as
flaming when you tip it with the tip lower than the bottle. I
believe what happens is that when the tip is not warm enough the
propane isn’t properly vaporized and so you get an excessive amount
of fuel. I’ve found that if I wait for the flame to heat the tip, or
separately heat the tip with another heat source, I can avoid this
flaming. I’ve also found that this doesn’t happen with all tips.
When I fuse fine silver rings for chains I prefer to use a plumber’s
torch. I find I can heat the ring up quickly by centering the flame
in the ring, focus on the joint for the fusing, then removing it
quickly. The comparatively low temperature of the flame allows me to
have greater control over the speed with which the metal heats up. I
tried using my Meco Midget, but didn’t have as much success. With
this method I am able to line up ring after ring in multiple lines
on a heat resistant surface and join them one after another with
about 95% success.
From an industrial side propane is a curious beast.
The bottles sit upright, so gas is always coming out of the top,
it’s not really going to come out any faster unless you adjust the
regulator, that’s what regulators do. I’ve found that it doesn’t make
a difference where I put the torch/burner with regard to the top of
the bottle.
Problems with propane tanks :-
Freezing up, as the gas is used the expansion of the liquid
propane to a gas makes the outside of the bottle very cold and it
starts to ice up, you will then find that your pressure drops.
Solution: Sit your propane bottle in a tub of water, and throw in a
few bottles of beer for good measure. You could always simply wait
for the tank to defrost… but where’s the fun in that?
A while back someone was telling me that if you tip you propane
cylinder on its side you will get more efficiency out of your gas.
This is actually a bad thing to do as you will waste a lot of gas,
and may blow liquid propane through your regulator and torch/burner.
Incorrect hose connection. Either not enough teflon tape or or
not tightened correctly. Gas fuses are okay, unless you want to put a
lot of PSI through your torch/burner. I usually use 15 PSI on my
forge, and higher for my furnace.
Hand held propane bottles (Bernzomatic) are a different kettle of
fish. The are designed to be used with the bottle inverted any which
way.
The torches being referred to in this thread are directly attached to
the small 1 lb propane cylinder like the Bernzmatic or other small
torches sold in hardware stores for soft solder plumbing repair not
the 20 lb and larger tanks used on your forge. So issues of freezing
and such are not going to be a problem. But you can get liquid
propane out of the small tank torch combination when it is tipped so
that the liquid is near the tank outlet. This results in the
“flaming” that Michael was referring to as there is too much propane
being sprayed into the venturi on the torch and you don’t get the
proper air gas ratio.
A word of caution here also. You mention using teflon tape on hose
connections. Standard hose connections used for welding and brazing
torches have a tapered face seal the threads are not used to
directly seal the connection and the use of teflon tape on any
standard torch, hose, regulator, tank thread is not only not needed
but can actually cause the face seals to leak if any of the tape gets
between the mating surfaces. I know on my two gas forges and many of
the gas forges used by blacksmiths most if not all the the fittings
are pipe threads and even some of the hoses I have seen used on these
forges use pipe threads. On the pipe threads the tapered thread is
what makes the seal and in that case the teflon tape or some other
lubricant (pipe dope) is needed allow for tightening the joint enough
to seal. But I have seen torch hose connections ruined in an attempt
to seal them with teflon tape as the fitting leaks and then more tape
is used and this additional tape and force used to try to seal the
fitting results in the distortion of the thin wall of the brass nut
and the fitting will no longer seal.
What James says about using Teflon tape to seal torch hoses is good
Pipe threads, such as he mentions used in a forge would be TAPER
threads which seal within the threads, they becoming sealed with
increased tightness of the joint. There is no bearing surface on the
end of the pipe itself. Teflon tape helps seal the imperfections
that come from machining the threads themselves. Also used is pipe
joint compound which, most commonly, has Teflon as a major component.
You could also use nothing, tightening the joint more and more until
there is no leak… but why? Teflon tape is cheap!
The joint used in a torch is a compression seal using straight
threads. The seal comes from the beveled seat on the end of the male
end which matches the beveled seat in the female receptacle. There is
no tape or joint compound needed on this, and as James said, can
actually prevent a proper seating of the beveled seal. Additionally,
if you used a joint compound with oil ingredients you could be asking
for real trouble if used on oxygen lines.
Teflon tape helps seal the imperfections that come from machining
the threads themselves.
FWIW: Teflon tape and many pipe joint compounds are intended as
lubricants not sealants. They will not seal an imperfectly cut or
damaged tapered thread, if the imperfections are slight enough they
will self correct during tightening but the real seal is from metal
to metal contact of the tapered threads. Without lubricant you cannot
tighten the threads sufficiently to insure a positive seal. So
applying too much teflon tape just makes it harder to seal the pipe.
There are some joint compounds that are sealants as well as
lubricants as they have a cyanoacrylate resin or other similar
material in them along with the teflon.