Been watching your vids and site for over 18 months now and you are much appreciated.
I am repairing a 30 year old hopper for a catering machine with TIG.
Done the main repair no problem but when filling a split in the case the filler is not adhering to the parent metal. It looks finished then when I polish it up it just flakes out leaving a hole that is getting worse. The more I try to fix it as the same problem is repeating. Using 316L rods, 1/16" lanthanated, 30amps high and 12 amps low pulsing at 250 hz. The place where it is failing is approx 0.0118 - 0.01968 inch (0.3 -0.5mm) sheet. I am sure it is stainless but this has got me beat. Could you give some advice please as this job is getting expensive (for me). This is the worst job I have done other than a rusty sports bike exhaust repair!
Doc from UK
any outside chance the metal is titanium?
that is what it sounds like.
if you put a grinder on it and it sparks much brighter than steel with bright yellowish white sparks then its titanium.
if it does not spark at all, it may be aluminum.
if it is either titanium or aluminum, you wont be able to weld it to the stainless.
if it is stainless, then getting some argon shielding to the back side might help..or at the least , some copper backing.