MIG welding and advice

[techhelpbb]

Originally Posted by JamesCH95

100% Ar is suggested by many, but is not always the best shielding gas. A helium/argon mix is best for welding aluminum (TIG or MIG imo) because helium has much better heat transfer properties. This lets gas-cooled torches run cooler, and transfers more heat to the work. Both of these increase the capabilities of the welder. I like 50/50 mixtures, but even 25% helium makes a big difference. Helium also helps create a more stable MIG arc.

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.