Flowmeter Set Up For Back Purge

[Peter Jack]

A long time ago I said I'd post pictures of the set up that I use when I'm back purging a weld joint. The pictured regulator allows individual control of the gas flow to the torch and to the purge. This results in a much higher quality weld, especially in stainless. When you're welding anything where the back purge isn't required just turn the purge flow off.

One thing to note is that it's obvious that I used Teflon tape to assemble things. I normally wouldn't do that but in this case that's what was available at the time. If you do use tape to assemble a pipe thread joint don't cover the first thread with the tape. That way there is a much smaller chance that a small piece of the tape will get into the assembly and cause issues.

One other note. Teflon tape is only used to seal tapered pipe thread. It doesn't work on straight thread, normally gasketed joints, compression fittings, etc. Used in any other application than the intended use it only makes things worse and harder to clean up. Nuff said!

Pete

[floydjer]

Sterling idea Peter, Thanks. I usualy disconnect the gas line from the mig and use that regulator. Your set-up is MUCH nicer. J.B.

[tallguy]

This may be only loosely related, at best, but here goes . . .

When GTAW welding aluminum, in some instances it can be useful to use a
mixture of helium and argon.  Helium acts as if it provides "more heat", although
it doesn't shield as well as argon does. 

If you use two separate flow regulators (one for helium and one for argon), this
allows you to "fine-tune" the mixture for nice results, instead of just having on-hand
a supply of pre-mixed, purchased gas (such as 25% He/75% Ar). 

[tallguy]

When back-purging, one should remember that the air being displaced (by the purging gas -- such as argon) must have a place
to go.  There should be an "escape route" for that air.  Once it is gone, a large flow of argon won't need to be maintained there.