Quote History Originally Posted By tinysd:
From your color description, it sounds like you are taking too long and dumping too much heat into the steel. That is the reason it goes from dark to shiny.
You want to establish the puddle quickly and start moving faster than you normally do with mild steel. Keep practicing. While practicing you will notice stainless distorts much worse than steel too.
You can try adjusting the amperage too. Sometimes I use more amps than recommended because it allows me to get the puddle fast and I run the bead faster than normal. It might seem counterintuitive, but it works.
I would practice that before changing cups.
Good luck.
Eta
I know @Seatbelts welds a ton of stainless, but it looks to be much thicker than 16 gauge. Hopefully he can lend his expertise.
View Quote
I don't know why I didn't get the tag but I would say about 90% of what I do now is 1/16th sheet stainless, mostly because I'm one of the only people who can weld it without sugaring it
. It can be a bitch to get it under control but your gonna hear me say a few things that run counter to commonly held advice.
The first being that your amperage is likely to low, and because your having to start a puddle so low and build it until you can add filer the reality is your likely overheating the material and thus its becoming sugared by the time you lay a bead.
Secondly a lot of people are obsessed with obsessively cleaning stainless prior to welding it. I won't tell you thats a bad thing, but I can tell you that unless I have something gunky on the stainless I don't clean shit. If your doing Xray level work then yes clean and remove as many variables as possible, or on certain materials but its just not necessary to clean shit or run a backside purge if you have the basics down. For me it all comes down to two things, first being time. The second being that I don't want to add anything else to the spicy air that is hexavalent chromiuim.
Without some pics its going to be hard to give you a good idea of exactly whats going on. It can be a plethora of things, from the wrong amperage to the wrong type of tungsten, to the travel speed and the filler rate. It sounds like its a amperage issue combined with a travel time issue and if your adding filler you may not be adding enough.
Here's some I took today. 1/16th 308ss sheet metal welded with 1/16th 308l filler welded using a combination of a Furick BBW and Jazzy 10. I run the jazzy for all but the outside fused joints, and I switch to the #18 BBW for this because the cone of gas shields both sides of the joint a lot better. I run about 35chf when I use these cups, so for me its not a problem to dump a good 10 sec post flow but you can probably get away with about 25cfh and a 7 sec post flow
All were run using an Idealarc made in 1990, with a fixed amperage of about 85-95. I don't use a pedal so when I strike an arc I'm at my hottest amperage and if its too hot I just have to readjust or move faster.
And a pro tip, if you can utilize aluminum in the process do it. If I have a joint that's over a few inches and I know I have to weld it all continuously, I will take a 1inch thick plate of aluminum and clamp it to the backside of the joint. It acts as a heat sink and will prevent a lot of sugaring if you keep it clamped tightly and hustle.