Acetylene tank size change

Jewelry Discussion
1

I have a Prestolite acetylene torch using a “B” size tank. I have
been asked to do some soldering demos at several shows. I am very
interested in doing this but I don’t want to haul around the tank.
Is there an inexpensive way to change to using the smaller tank (that
I know is available), just for these instances. Is there a different
regulator that will work so I can use the smaller tank? Any info
would be helpful.

Debbie
DeMoy Jewelry Designs

2

Hi Debbie,

You’re looking for an “MC” tank. (“MC”=“Motorcycle”. They used to use
them to supply acetylene to the gas burning headlights on early
motorcycles…)

I’ve never used one, but my memory is that they have a smaller
coupler than the standard “B” connectors. I’m sure the gas house can
sell you a converter coupling. Your normal acetylene regulator
should work just fine. (Keeping in mind that the “B” is also a
nonstandard connector, so if you have a full-size reg, you may
already have a converter on it. You wouldn’t want to have two piled
on top of each other if you can avoid it. So in that case, pull off
the “B” adaptor, and switch out for the “MC”.) If you have the
simpler single dial reg that normally comes with “B” tank torches,
it’s already got a “B” fitting on it, so you’re looking for a B-to-MC
adaptor.

Best of luck,
Brian.

3 
Is there an inexpensive way to change to using the smaller tank
(that I know is available), just for these instances. Is there a
different regulator that will work so I can use the smaller tank?
Any info would be helpful.

The fitting should be the same, but bear in mind - an acetylene tank
can only output so much gas. If the torch requires acetylene flow at
a rate faster than the tank can handle, you’ll end up sucking some
acetone out with it. This is because on the inside of the tank
there’s sort of a honey comb structure, and the acetylene is
dissolved in acetone. This is because normally, if one compresses
acetylene much above 15psi it has a propensity for exploding.

It’s important to make sure that the tank you use can supply enough
gas to run the torch, or you’ll only be able to run the torch for a
few minutes, have to shut down for a bit, then start up again.

Paul Anderson

4

Hi Debbie:

The small MC tank has a different size regulator fitting. Your local
welding supply shop should be able to order or make an adapter for
$15 - $20.

Good luck,
Fred

5 
The fitting should be the same,

No it is not, the small tank is an MC tank with a smaller CGA 200
connecter and the typical tank used by most jewelry folks is the B
tank with a CGA 520 connector. Yes there are adaptors and yes a MC
tank will work fine with a prestolite type torch.

James Binnion
James Binnion Metal Arts

6 
The fitting should be the same,

No it is not, the small tank is an MC tank with a smaller CGA 200
connecter and the typical tank used by most jewelry folks is the B
tank with a CGA 520 connector. Yes there are adaptors and yes a MC
tank will work fine with a prestolite type torch.

James Binnion
James Binnion Metal Arts

7

Debbie,

Consider having the sponsor of the shows provide for your fuel
needs. An alternative would be to procure a small propane tank that
is refillable. This system accepts a regulator, hose and torch tip
and handle. " Smith" would be a good manufacturer for the regulator
etc. Refer to Otto Frei Co. for a description of the above system.
Propane and acetylene hoses, torch tips and handles are not
interchangeable.

rp leaf

8 
No it is not, the small tank is an MC tank with a smaller CGA 200
connecter and the typical tank used by most jewelry folks is the B
tank with a CGA 520 connector.

I stand corrected. Most of my experience has been with bigger tanks.

Paul Anderson