Parallel machines?

[delaet20]

I have seen in a few places on here where people have mentioned hooking multiple machines together to increase amperage. The idea interests me. I have searched this both here and on the net, and have not found a lot of info.

I also read on miller's page on paralleling and they recommend diode rather then dc brush machines.

The only machines I have are some old sa200s. Can you do it with these, as I do a fair bit of air-arcing, and more amperage is better. Do they have to be identical machines? I have a short hood and a red face.

Any info would be appreciated, as I know there is a lot of knowledge on this forum.