Once you get to 16 ga and thinner stainless steel lap joints, it becomes a delicate dance of hot enough....but not too hot.
Stainless steel needs a bit less amperage than carbon steel.
In fact, usually about 2/3 the amperage needed for carbon steel.
For example, if a .063" thick carbon steel weld requires 63 amps, the same stainless steel weld might require only around 43-47 amps.
Of course there are other variables that can affect this but 2/3 is a pretty good rule of thumb...especially when you are first learning.
As you get more comfortable and proficient, using a bit more amperage can help you increase travel speed.
Stainless steel has low thermal conductivity...meaning heat can build up quickly.
But that doesn't mean stainless should be welded cold and slow.
you do need to use enough amperage to get a puddle established quickly so that you can get moving to outrun the heat.
3 seconds is the max...
2 seconds is even better. if you can get the puddle moving within 2 seconds, you can avoid heat buildup and get better results on stainless.
For this lap joint on .056" thick stainless steel, I only needed 47 amps.
I used .045" er308L filler metal and a Jazzy #10 ceramic cup with 25-30 cfh argon.
The Ceramic jazzy 10 is one of my favorite cups for stainless.
you can get yours in a 2 pack or with a kit like our Arsenal or Challenger kits.
The kits are convenient because they have all the right hardware needed.
All you need to do is pick the right kit for your torch and you can be sure everything will work. ( the video above will get you dialed in on your torch)
click images below to learn more about our Weldmonger/Furick Arsenal kits designed to get you the best results possible on carbon, stainless, nickel, and titanium alloys.
