I've got a 40 cuf argon bottle with a cheap lincoln electric mig, which
works nicely on aluminum, but leaves low penetration on steel. I want
to make a mixing manifold for argon and co2, but I don't want to spend
$100 for a co2 cylinder. Using a C25 mix, a 16 oz paintball tank holds
about 10 cubic feet, which would require refilling about when the argon
is out. Paintball cylinders cost about $20, and refills cost under $5.
Would it be possible to use a paintball co2 tank with a mixing
manifold for welding? How would I lower the pressure in the co2 tank
(~800 psi) to something close to the regulated argon outlet? A few
needle valves in series with a pressure gauge? Something more
I think you are going to need a regulator for the CO2. Using a needle
valve you could get the mixture right while the gas is flowing. But
when the gas solenoid in the MIG welder was off the CO2 would keep on
coming until it blew out something.
So I would look on Ebay for a CO2 regulator and while you are at it
look for CO2 tanks and CO2 fire extinguishers. I expect some of the
places that sell CO2 fire extinguishers would put in a valve as used
for welding before they shipped.
A 20 lb CO2 cylinder is not all that expensive, and getting it filled
is cheap compared to getting 20 refills of a 16 oz paintball tank.
PS You can get an adapter to allow you to put your argon regulator on
a CO2 bottle and use straight CO2. Not quite as good as C25, but not
all that bad.
Jeremy Samuels wrote:
The problem is I haven't had to refill my argon cylinder yet in the
half year I've had it, and the pressure is still high. Looking at my
argon regulator, I realized that the entire inlet nut can be unscrewed,
and it looks like a NPT fitting. So I buy a $15 CO2 tank, $5 hose with
a 1/8" NPT fitting, a $20 regulator, and some fittings and pressure
gauges for mixing the gasses, which couldn't be more than $70 total,
versus a $100 co2 tank, and $20 regulator, not to mention the $30 in
fittings. For what little welding I do, it would make sense to save
the $50 and get a smaller tank. Any idea how to measure the flow of
the gases? Would pressure gauges work?
The simplist thing I know of to check flow is a gallon zip lock bag.
Time how long it takes to fill the bag and then do the math to convert
from seconds per gallon to cubic feet per hour.
I don't know where you are, but I would try to find a CO2 tank in your
local area because shipping costs money. But I would try some searches
on Ebay. Both CO2 tank and CO2 cylinder. You might be able to score a
20 lb tank in your area for less than $25. I have found tanks at the
local salvage yard, but not often. I think I had to pay $5 for the
last one, plus $16.66 to get it hydrostat tested ( and of course some
for getting gas, I swapped it for a 40 cft tank of C-25 ). I just
think you would be happier in the long run with a 20 lb CO2 tank if it
cost less than $30.
You might get it to work with two flometers and as equal pressure on
each as possible.
Or, you can do like I do and run straight CO2 for mild steel. It's
remarkably cheap, does a good job, some people seem to not like the fact
it spatters a bit more but I don't really notice it. If I'm working on
something really nice I'm going to hit it with the sander to get the
spatter regardless, and if the work doesn't require that approach then
it's no big deal.