Hi, I just had a go at welding som stainless today, and noticed that it tends to twist and bend a hole lot. is there any tricks to minimise this? I realize that clamps and jigs will help but there will still be a lot tension in the steel.

I'm tig welding if that makes a diffrence.

 

hmmm... well no matter what you do, your going to warp the **** out of stainless.


BUT, you can minimize it. Start as cold as possible, if your scratch starting dont even get it hot enough to contaminate the electrode, and try it on a similar thickness metal before the work, slowly turn it up a few amps, until you can bairly see a puddle forming, get the smallest size tungsten and filler. usually 1/16th is good and .035 filler. on to 1/4 thick stainless a size 4 cup works well, with 35 cfm of argon flow. a bigger cup requires less cfm to get the same amount of weld coverage.


if your welding with high frequency, than basically turn the heat down at the machine, so you have a very fine adjustment at your pedal/****, and turn it down so you can hear the hf, than slowly go up in amperage until you can bairly see the puddle forming. if needed to start the bead add a touch of filler, because stainless is a bitch and alot of times wont fuse on its own.


oh, and most important, BRUSH THE **** OUT OF IT WITH A STAINLESS BRUSH UNTIL IT SHINES AND YOU CAN SEE SCRATCHES IN THE STAINLESS OTHERWISE YOUR GOING TO expletive IT UP. this is the most important part on welding stainless and aluminum. the oxide layer on the stainless has a higher melting temp, and therefore it has to be much hotter to get the puddle going. hot stainless = FUBARD work. remember, tig welding is only for people with extream patientce.

 

yep stainless is like that -

but the more you work with it the more you get a feel for where its going or wants to go. remember, stainless has more thermal creep than almost any other common metal. meaning if you drilled a couple holes 12" apart on a few different grades of steel, stainless, aluminum, etc. then subject them to the same heat conditions, the stainless will move so much the holes wont line up anymore, and when cooled, it wont nessecerily go back to its start point.

if youve seen those spagetti headers on older F1 cars youll notice all kinds of slip joints with springs so the thing can expand and relax. if it were gusseted up, it would just fatigue and fail at the point of least resistence.

also - heaver material can help, picture heating up a block vs. a thin sheet. and sometimes (although not all) preheating can save the day as well.

good luck