If you have "city gas" available to you, I think there is none better for jewelry use
This may sound (be) pretty ignorant, but can you hook up just any
torch to any gas, if you have the right regulator? I have only used
Smith and Prestolite torches with air/acetylene, and a little torch
with oxy/acet. I would like to set up a torch at home, and have natural
gas available. I would hate to buy a torch only to find I couldn’t use
it! --Noel
My experience has been that usually newbie’s (like myself) use the
Prestolite torch and a B Cylinder of Acetylene. The Prestolite comes
with lots of tips, it is what is used in most colleges (they have them
here at Pima College in Tucson) as well as the Rock Club here…I
have used others as well. I actually love the little Butane Torches
for small work, it is fast, clean and easy to use anywhere! I would
recommend the Prestolite, I also have a Oxy Propane torch for glass
work, the Prestolite saves you the need to buy oxygen (rather
expensive after a long time, I pay 20.00 a cylinder to have a large
one filled, and I use about 1 a week right now…I want an oxygen
generator! Thank you so much
first, marco, let me restate that I feel that in many cases, people
get overly worried about this danger. Yes, it’s real. But common
sense and good workshop practice should allow a safe setup and safe
use for most of us, if we need to use propane. As to what size can be
dangerous? Heck. Any size. The little hand size tanks are hard to
damage, and don’t have all THAT much propane in them. So a slowly
leaking one will run dry before it can do much damage in most
situations. But if you damage the valve area on a full one, causing
a fast leak while your holding the thing, and it ignites, you better
believe you could have a serious problem on your hand. And anything
larger than that, like even the smallest of the BBQ size tanks, can be
more hazardous still. But lets try to remember that these propane
tanks are sold in every hardware store, and gas stations, and even
some grocery stores, and refilled all over the place. They get sold
to people who’ll operate them while totally drunk and trying to
barbaque their dinner while attempting to remain in the standing
position, still drinking their beer. Only a small number of these
idiot manage to barbaque themselves in the process. Those of us with
actual brains connected to our hands, and with those brains turned on
and at least partially functional, should be able to use these tanks
in a safe enough manner, once we know what the potential dangers are,
and take care to see that the equipment is used correctly, and
maintained correctly.
Peter
do you think he suggested the acetylene because acetylene gets hotter and without oxygen i might need the extra heat?"
Yes, it’s substantially hotter, and that makes that single
“prestolite” torch generally more versatile than any other single tank
torch.
Soldering silver will be quicker and produce less fire scale with a
quick hot torch. (Keeping a piece of silver hot for a long time
produces the WORST firescale of all) If all you are doing is small
work at lower temperatures, then propane/air is ok. But if your pieces
are large enough that it takes a long time for them to get hot enough
to solder, then you’ll wish you had the hotter torch. Then at that
point the choice may be an added oxygen tank with the propane. If you
want to melt enough metal to cast it, you’ll need oxygen with your
propane. But an acetylene/air torch can (barely) be used to melt and
cast silver or gold, as well as solder fairly large pieces, so you can
do a wider range of work with one acetylene tank and one torch with
several tips. Later, if you want even more heat (pyros always want
more heat!) you can add oxygen with an oxyacetylene torch and melt
STEEL! – welding – which, as it turns out, is quite valuable for
toolmaking or building kilns, etc., in the course of non-ferris
metalsmithing.
Personally, if I had my first choice in everything, I’d have one of
each of all of them, with all the possible sizes of tips, including a
self-fluxing torch for hollow ware and a large hydrogen/oxygen torch
for casting.
Alan Heugh
http://www.nas.com/~aheugh/
Hydrogen is, compared to propane or acetylene or natural gas,
considerably safer in that it dissipates from a leak at very high
speeds, and is essentially non toxic. but bottlet hydrogen does not
include an odor, so a leak won’t be as noticable. And as the
passengers of the Hindenburg found out, hydrogen in a sufficiently
closed space, leaking, can also become an explosive mix. the tanks
are under high pressure,so need greater caution in preventing the
tank from falling over. And as you note, it needs it’s own special
type of regulator.
It has both pros and cons. It’s the hottest of the fuel gas flames,
when burned with enough oxygen. Often, people use it rather reducing,
since a true neutral flame is just so damned hot. This highly
reducing flame does tend to protect the metal very well from oxygen in
the air, since the excess hydrogen in the flame is an extremely
agressive oxygen “getter”.
One of the esoteric causes of porosity, especially in golds, and
especially in white golds, is the formation of gold or nickle
carbides, formed by reaction of the hot metal with excess carbon in
the reduing flames of acetylene, propane, or natural gas flames (or
from melting in graphite crucibles if they’re getting older). Since
hydrogen does not have any carbon, this problem is completely avoided.
However, the flame is difficult to see, especially when reducing, and
takes practice to control. also, if you’re using a more neutral flame
(more oxygen), then the temperature of the flame will be high enough
to be generating somewhat significant amounts of ultraviolet. Such
use suggests some sort of eye protection that protects for UV.
Personally, at work, I cast with hydrogen. they got it installed
back when they were still trying to cast platinum (this is far and
away the best fuel for melting platinum), and it’s still the casting
torch’s fuel. I’ve gotton used to it well enough, and it works just
fine. But frankly, I still prefer my own setup at home, which is oxy
propane. Perhaps this is just that I’ve more years of experience with
it. But I like being able to see the flame, and I understand what
it’s doing better. My castings at home are better than what we get
at work, but then at home, I’m also usually using small flasks, and a
centrifuge. So it’s hard to say whether it’s the gas or not. I
suspect it’s more the casting method and flask temps than the fuel
gas, that’s the difference.
As to fire scaled silver castings, I’d be surprised if this really
fixes things. Yes, the hydrogen flame is very kind to the
melting/molten silver. But once poured, the silver is then reacting
with air trapped in the pores of the investment, as well as with the
investment itself. Do your silver castings come out of the investment
black? It’s not a function of the torch, it’s the investment. And
this is a bugger to fix. Even companies using induction melt casting
machines, which totally protect the melting metal with shield gases,
and sometimes even see that the atmosphere being drawn through the
flask is also a shield gas, still get oxidiation and sulphide
formation of the sterling silver castings. Your hydrogen torch will
help you with porosity in the casting due to oxidation of the silver
during melting. But it won’t completely solve the firescale problems
in sterling castings.
peter Rowe
There aren’t many things to consider. So this will be shorter.
There are two main types of regulator. Oxygen and fuel gas. You
cannot interchange them, since the threads are different.
Oxygen regulators, in particular, must NEVER be lubricated with
anything. Well, there are a few things that can be used, but don’t
YOU do it. Leave it to the welding shops if your regulator needs
service. Any petrolium based lubricant in the high pressure side of
an oxygen regulator can cause the regulator to explode when high
pressure oxygen hits it, since things that are only mildly flammable
in air, can be come unstable and highly explosive in pure oxygen at
2200 psi.
For good measure, don’t oil the fuel gas regulators either. They
should never need it. If they do, then it’s time to have the
regulator professionally overhauled and cleaned properly. The reason
is that if something you can see is sticking, like the adjustment
knob/handle, then the diaphram inside may also not be functioning
quite as it should, which can lead to leaks.
Use oxygen regulators only for oxygen. Nothing else.
but acetylene regulators can be used for propane or natural gas tanks
also. What you should not do, though, is take an acetylene regulator
off a propane or natural gas tank and put it back on an acetylene
tank, without having it cleaned and service first. I’m not quite
certain what the conflict there is, but I’ve heard it from many
welding supply houses, who’re the experts on regulator care and
feeding, after all.
And don’t expect to take the cheap propane or natural gas regulators,
like those used on bbq tanks, the ones without guages, and move them
to an acetylene tank. won’t work. Don’t do it.
When storing a regulator, be sure the inlet side (tank side)
connection in particular is properly covered/capped. You don’t want
dirt to get into the high pressure side. For the same reason, when
mounting a regulator, any type, on any tank, first crack open the
valve on the tank for a moment. to blow out any dirt that might have
become lodged inside the connection. Then be sure, in connecting to
the tank, that all connections are tight and secure. Close off all
output valves or lines from the regulator, and screw OUT the
adjustment knob. Now open the tank valve. The high pressure guage
should show you the tank pressure, and the low pressure side should
still read zero, sinc eyou’ve got that side screwed out/turned off.
Now close the tank valve again. The high pressure needle should stay
put, not sink lower. If it looses pressure, then either the regulator
needs service, or the connection to the tank is leaking. Now close all
torch valves, but open any valves to the torch lines themselves. Open
the tank valve again, and screw in the regulator knob to a normal
working pressure. Not turn off the tank valve. for many of us, if
you’ve got more than one torch, or are running lines around, the tank
guage will now slowly start to loose pressure, since it’s difficult to
get a complex setup put together that does not have at least a minor
leak somewhere. But the rate of that pressure loos tells you how much
gas you’re leaking, any time the tanks are on. If it’s excessive,
find and correct the situation. Use soapy water to find gas leaks.
Never a match or flame.
As to adjustments themselves, it varies a great deal on what sort of
fuel, what sort of torch and tip, and what you’re doing. Melting
platinum will require higher oxy pressures than if you’re using a
small tip to solder thin gold wires. You’ll need to experiment here to
find out what works best. Often torch manufacturers can suggest
proper pressures for specific tips or torches.
When you’re done with your torch, turn off the tank after turning off
the torch itself. open a torch valve to bleed the lines, thus
draining the pressure from the regulator. now unscrew the adjusment
knob till it’s no longer putting pressure on the diaphram.
I’m sure there are other points that other people will bring up.
This is just what occurs to me at the moment. Anyone else?
Peter Rowe
I only worked in a shop which used natural gas; I have never “tooled
up” for natural gas I don’t have specifics. I believe manufacturers
provide different orifices for different fuel gases. Even if there is
some minor conversion expense natural gas is a great way to do
jewelry work if you have access.
Jim Small
Small Wonders
Peter, I’m sure that many of us have the Prestolite setup for
acetylene with a single volume gauge but no indicator of pressure. Is
there any way to tell by the flame, the status of the pressure? With
that sort of setup is it appropriate to relieve the pressure on the
diaphragm as well, at the end of the day? Presently, I shut off the
tank, then bleed the line and close the line at the handle. I do not
have a flame arrester, but am thinking that perhaps I should include
a pressure gauge and flame arrester to my setup. What is your opinion?
Thanks for increasing the base!
Susan Ronan
Hello Noel
So far as a torch for natural gas, I checked the Rio catalogue and
they note that the basic Little Torch for Propane is compatible with
natural gas and oxygen. The regulators and tips do change from gas
to gas.
I think you’ll get better service if you just go to the local welding
supply company and talk to an experienced person there. If they
don’t have the exact torch in stock that you need, they can easily
order it. They also have the regulators and necessary compressed
oxygen. I got my torch from Frei and Borell, and love it. Judy in
Kansas
Judy M. Willingham, R.S.
Extension Associate
221 Call Hall Kansas State Univerisity
Manhattan KS 66506
(785) 532-1213 FAX (785) 532-5681
I am old and simple in my approach to pretty much everything…so
take that into account. Advice on torches? Anything you pick will be
fine. They all have advantages and disadvantages. Personally I have
5 torches I use. Two are oxy-acetylene. Two are oxy-propane. The
last is an acetylene only Prestolite. If your goal is to to heat
metals to fuse-solder-melt temperatures, like mine, then they all
solve the problem. Don’t overthink this. The Prestolite was the
torch I began on because it is simple and doesn’t produce an oxidizing
flame. Did lots of work. The finer work is better achieved with
other torches. Pin point heat, higher heat, etc. Just pick a torch
and start melting metal. You will buy another one anyway.
Norman
Peter
Thanks for the post on oxy-hydrogen torches. I have a couple of
additional thoughts.
Copper (and nickle if I remember correctly) absorbs hydrogen when
in the molten state just like silver absorbs oxygen. If you use a
reducing flame when melting alloys that contain copper and nickle
with oxy-hydrogen you will have gas porosity problems from the excess
hydrogen.
Hydrogen reduces the temperature at which the Gypsum (calcium
sulfate)bonded investments break down and liberate sulfur dioxide
which is absorbed by the molten metal and is a major cause of gas
porosity and discoloration of the castings surface due to the
formation of silver and copper sulfides. This temperature is at best
just above the pouring temperature of sterling silver When there are
things like carbon left in the mold from improper burn out and or
free hydrogen in the atmosphere or dissolved in the metal this
reaction temperature is lowered and you start singing the porosity
blues.
In centrifuge casting the extreme heat of the oxy-hydrogen torch
flame that exits through the crucible opening will also break down
the investment causing surface roughness and gas porosity
Oxy-hydrogen is a great fuel for platinum casting but I would stay
away from it for any other kind of work.
As for the black surface on your castings if you do every thing
right it is just an oxide layer and will literally rub off with your
finger. I built a casting machine that keeps the flask totally
enclosed in a inert gas environment. If you let the flask cool down
to for 4-5 min in an inert gas then quench the silver castings break
out white but if you pull the flask out of the machine sooner and
let it sit in air or allow it to cool to room temp before breaking
out like for stone in place casting they will be grey to black . The
investment is porous and allows the oxygen to get to the metal also
the button is exposed and some oxygen can be absorbed and transported
through the casting from the button.
Jim
jbin@well.com
James Binnion Metal Arts
4701 San Leandro St #18
Oakland, CA 94601
510-533-5108
I hope this is a final comment on the Oxy-Acetylene.
Some advice on regulators: On the Oxygen tank, open the valve all the
way until it stops. This is called back seating. It will allow any
amount of oxygen to be released, but not allow it to escape around the
regulator stem.
For Acetylene, and other fuel gasses, open the valve about 1/4 turn.
Just enough to allow the gas to flow. The reason should be obvious,
if something happens, anything, you don’t want to spend a lot of
time closing the valve.
Be Safe,
Rodger
Hello Peter,
Hey,this was a easy to read article fellow !!I loved it! I thaught
lots of students how to work with a torch in order to melt gold or
silver and I was really surprised that the majority of the students
are not aware of the interaction of gas and oil.Some of them thought
that they had to use some oil to lubricate the treads on the gauges
or regulators.So I agree with you and the danger of products is more
related to the persons knowledge about this product then to the
product itself.I’m not saying that gasses are save but you have to
take your precautions in order to work save and that counts for
everything with a dangerous potential.In the middle ages people
swallowed diamond powder since they thought that the mysterious
diamond would heal them.In matter of fact this is the most painfull
dead you can wish.Hunderds of thousand little rasor like particles
cutting your intestinal tract a part …but they didn’t know . If
you really don’t know … don’t mess around with it.
Regards Pedro
Palonso@t-online.de
They get sold to people who'll operate them while totally drunk and trying to barbaque their dinner while attempting to remain in the standing position, still drinking their beer.
Have you been looking over my fence…hahahaha…??
The reason for not switching a regulator from Acetylene to Propane
(or any fuel gas for that matter) is that all of the fuel gases are
oil based. They will leave an oil residue in the hoses and in the
regulator. There are two type hoses involved for gases. Fuel Gases
such as Propane, Propalene, Mapp Gas, and the newest Chemolene, all
have an oil base and have to use hoses marked “T”, which are
impervious to oil. Acetylene on the other hand uses an “R” type
hose, which is rubber based. It will melt, get soft, bubble up, and
deteriorate if used for fuel gases, and the parts that come off can
clog your regulator. If the regulator is used for fuel gas, then
switched back to Acetylene, it will have traces of oil in it, which
could possibly harm your hoses.
Love and God Bless
-randy
http://www.rocksmyth.com
Home 214-321-6253
Work 469-775-6650
Cell 214-213-0777
I didn't think of myself as a timid person before the issue of fuel gasses.."
I have to admit that after reading all of the postings on
oxyacetylene, I plan to sell my B tanks with three torches attached
(regular, mini & Prestolite) and to exchange the B oxy. tank that I
use with natural gas to a very small one, and refill more often.
During the ten years I taught at three different schools, I often
carried my tanks back and forth, and have had them in my studio, just
outside of my home for many years. I now realize what a huge risk I
have been taking with my home and car insurance not to mention my
life.
I’m going to miss them, but I would rather be safe. And that means my
casting machine goes too. Like to above writer, it will make more
room for my growing collection of oil paintings and the model, toxic
paint and all, better than blowing up.
I hope we haven’t frightened off all of the young people.
I think maybe this thread has over-emphasized the potential dangers
of these fuels. There is no need to remove any of them from your
lives to remain safe in your home/studio/shops. The point was they
are safe if contained. Potentially unsafe, only potentially, if
released. The incidence of explosive accidents is very very low.
Your chances of maiming injuries are much higher every time you drive
your car or cross the street. That said I am moving off my
soapbox…except: Anyone else out there witness the exposive
results of airborne dust particles? Like sanding dust or grain dust
in a silo? Just watch those combustible/oxygen ratios.
Rachel Hayward wrote:
Peter, I'm sure that many of us have the Prestolite setup for acetylene with a single volume gauge but no indicator of pressure. Is there any way to tell by the flame, the status of the pressure?
Sure. If you’re flame is too anaemic to do the job you’re asking of
it, crank up the pressure some more. This regulator won’t give you
more pressure than is safe, so don’t worry about overdoing it. You
don’t need to be more precise with this type of torch. That’s why
they don’t bother with the second guage.
With that sort of setup is it appropriate to relieve the pressure on the diaphragm as well, at the end of the day?
Yes, of course. whether or not there is a second guage on the
regulator affects the price of the regulator, but not the operation of
the diaphram. It should always be released again when the tank is
shut down.
Presently, I shut off the tank, then bleed the line and close the line at the handle.
This removes the pressure of the gas on the diaphram, but it does not
remove the pressure from the adjustment knob on the diaphram, which
over time, could then become deformed by that constant pressure. It’s
a minor point, but releasing it at the end of the day will increase
the lifespan of the regulator.
I do not have a flame arrester, but am thinking that perhaps I should include a pressure gauge and flame arrester to my setup. What is your opinion?
The biggest danger that a backcheck valve protects against, is this:
On a two tank system, if you’ve got oxygen and gas pressures set very
differently, then, especially with a smaller tip, it is possible for
oxygen to back up into the gas line if the oxy pressure is much higher
than the gas pressure, or the gas into the oxy line if the other way
around. Not easy, but possible. In that case, you’ve then got a
flammable mix in the hoses. Normally, the nature of the torch is that
flame/combustion stays outside the torch, but if it should flash back
into the torch, at worst you want it to go no farther than where the
gasses mix, “downwind” from the valves. If there has been backflow
from one gas line to the other, then the flame can get back from the
torch itself into the hoses. Or worse, into the regulators
themselves. Obviously, this would be quite dangerous, since if it
makes it to the regulator, it could then explode. Even if it just
burns a hole into the torch hoses, it’s not a pretty thing to have
happen.
with a single tank, like a prestolite, there is virtually no way for
gas to flow backwards. When you first turn the tank on, there’s air
in the line, but it’s quickly purged by incoming gas. Gas without
oxygen does not burn, thus there’s little chance of a flashback. Thus
a backcheck valve on a single tank torch is probably not needed. But
if it makes you feel safer, go ahead and put one on. (I’m sure your
welding supply dealer will be happy for the sale) And if you ever add
an oxygen tank to your acetylene, with a torch designed for both
gases, then they are pretty much required on both lines.
Peter