tips for stainless mig

I have acquired the necessary material and a 6 foot long 24 inch diameter stainless roller that I am going to build a grill out of ,need some tips on using mig on stainless

all matl, is @ .125 have my choice of miller 251 mig or Lincoln commander 500 with suitcase feeder miller synchro 350 tig{ I prefer not to tig this as quite a bit of welding to accomplish?

any hints or tips

Reply to
williamhenry
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Millermatic 251

0.030" 308L (or 309L) filler wire, just buy a 10lb. spool. You can use standard C25 gas (75% argon/25% CO2), but the welds will be very grey afterwards. A better gas is a helium or oxygen tri-mix. Your local welding supplier should be able to rent small bottle of either for this small job.

With stainless MIG you have to keep your wire stickout extremely short. It helps a lot to have the tip about 1/8" to 1/4" proud of the gas cup. The 251 should have a settings chart inside the door.

Reply to
Ernie Leimkuhler

we have 88/10/2 mix at work and some 035 308wire

do I need to pretreat the area , or post treat the weld with any chemical? I would like a nice looking finished weld ,

though I am willing to hit all the welds with a surface prep wheel in necessary

Reply to
williamhenry

No matter what you will always get an obvious oxide grey oxide layer after MIG welding stainless steel.

A stainless steel wire brush on a grinder will likley buff it away.

You will still have to passivate the stainless if this part is for marine, food service or medical applications.

Reply to
Ernie Leimkuhler

ok how do I passivate it?

Reply to
williamhenry

Pickling paste is available from most welding suppliers. Nasty toxic stuff, but it works.

I use a citric acid solution called Citrisurf which is applied with electricity.

There are passivation shops anywhere there is a boat industry. They can passivate parts for you.

Reply to
Ernie Leimkuhler

Is that the same stuff you use for cutting fluid on aluminum?

Ted

Reply to
Ted Edwards

No that is Big Orange from Zep.

Zep

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Reply to
Ernie Leimkuhler

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