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Changing Little Torch to Propane


I have a brand new studio and want to change my Little Torch from
acetylene to propane/map gas.

Do I need new regulators or will my current ones work?


always change your hoses and make certain you are using a acetylene
regulator for acetylene and propane for propane…they are not
interchangeable .you may also need a new orifice and/or filter
depending on the style of torch you have…the one regulator that can
be reused is the O2.&.if you put a “y” connector on it you may then
use both fuel gasses on seperate lines with a single oxygen tank, the
y connect and 2 appropriate lines to the torch using x gas…also
propane and mapp gas require different regulators…and depending on
the style torch you have perhaps orifice modification ( but that
voids any warranty)…check your smith manual, as i don’t think you
can use mapp with it…i could be wrong but i think i remeber reading
it somewhere in their literature…



The regulators for acetylene are different.



I thought that the shop was wrong when they told me just to swap
over the tanks!

You might have all saved my life!

Tony Konrath


Different regs required. But you might be able to use the same tips
if you make a small alteration to the exit hole. Propane nozzles
require a recessed hole. I’ve found it’s easy enough to do with a
ball burr where the tip size is reasonably large.


Brian Adam



The only difference between an acetylene regulator and a LP (propane)
regulator is the outlet side gage, the inlet connector and possibly
the LP regulator may have a higher pressure delivery on the output as
it is not unusual to use propane at 50 psi in industrial settings and
it is potentially explosive to use acetylene at anything over 15psi
but most acetylene regulators will produce 20-30 psi if you are
foolish enough to set it there. Fuel gas regulators are manufactured
for use with any one of several gasses including acetylene propane
and MAPP. It is the outlet pressure gage and tank fitting on the
inlet that determine which gas they are used with. So in that view
the person at the shop was right.

There is really only one danger in going from acetylene to propane
with your regulator. If it has been in service a long time with a
large amount of acetylene passed through it there is a chance that
some acetylene compounds (sometimes referred to as varnish) have
built up in the internal areas of the regulator and could cause an
explosion if they were pressurized to above 15 psi. This is not
highly likely but still is a potential problem so there is a real
reason for not just converting it. Before I knew about this I had an
acetylene regulator converted and did not have any problems but it
was not in acetylene service for an extended period of time. I do not
belive that I have ever seen a reference to an accident caused by
this but when working with pressurized gasses you really do want to
be on the safe side of things.

James Binnion
James Binnion Metal Arts


The regulators for acetylene are different. (than propane ones) 

The regulators are virtually the same. Because acetylene is
dangerous above 15 psi, the manufacturer paints a red line on the
"acetylene" version. Propane has no such restriction so there is no
red line and it can be used at much higher pressures. The hoses ARE
different. Acetylene uses a “R” hose and propane uses a “T” hose. An
acetylene hose will start to break down if used with propane. Some
tips are different. The Little Torch tips can be used for both -
except that the smallest tips will not stay lit with propane.
Another example of different tips are those used on the Smith torch
used in many workshops that uses atmospheric air. (found in many
classroom studios) The body of the torch can be used for either
fuel. Most of these are used with acetylene and the tips that look
like a long, bent tube. The propane tip that is used on the same
torch body has a much larger tube fastened on the end. The purpose
of the extra tube on the end is to introduce more air because
propane needs much more oxygen for the same amount of heat as
acetylene. Here is the link to the Smith site that shows pictures of
the propane tips. They are not as common as the acetylene, but put
off a large, diffused flame that is great for larger soldering jobs.

Mitch Adams