MIG welding and advice

[JamesCH95]

Originally Posted by techhelpbb

Absolutely correct.

However I rarely do that because I have a handy propane torch to preheat if need be and my welder is getting up there in power capability.

So I was curious (it's been a while) I called AWISCO where I buy my gas and they are getting back to me about the cost difference between the custom mix of 25% Helium / 75% Argon (I bought my previous tank elsewhere and apparently this was something unusual for them) and 100% Argon.

Last I looked the cost of the mixed gasses can reach a point where the cost of savings of the machine (though a donate machine can skew this) can make more sense to buy a more powerful welder (because it's cheaper over usage). Course if your usage is really low maybe it doesn't matter.

You can get a welding gas mixer but they are not typically cheap.

It's true that helium is pricey, and helium prices have spiked recently. My last price out was (in round numbers) $100 for Ar and around $250 for 50/50 (special order). This was for a 300ft^3 bottle refill. FWIW I have used 50/50 and 100ar with a Lincoln Precision TIG 375, their top-end TIG machine at the time, and much preferred 50/50 for aluminum as compared to 100ar.

At work we use a gas mixer, that was a little over a grand. I'm sure one could make their own crude gas mixer for not huge amount of money though, i.e. just 50/50, not 10/90-90/10 like a high-end mixer.

Looking around on the internet, some people think 50/50 is too much helium and suggest between 25/75 down to 5/95. Last time I checked 50/50, 25/75, and 10/90 are available OTS.