Welding Tips and Tricks

So, i've got a project i'm about to start working on with a friend, involving some 16ga 304 stainless. The key is, i'm going to be doing some welds on the inside, that i DONT want visible on the backside. No 100% penetration wanted. My welder is a Northern Tool 115v inverter, 80a max, goes down to 20a....obviously scratch start, i've got a 9v torch, 3/32 (or 1/16) 2% Thoriated, stubby gas lens kit..for now, i'm practicing on some 16ga mild steel, i know it wont QUITE be the same, but it's close enough to practice on....er70s2 for now, and 308L for when i do the stainless....

Anyway, if i do 50a, i'm getting 100% penetration on fillet welds, no problem at all....if i do 30a, i'm still getting a ton of burn through to the backside...i dont WANT to back purge, as i only have a 20cf tank, so i'd rather not eat up more gas than i need....i dont NEED 100% penetration on this job, as it will hold together fine without, and wont kill anyone if it breaks lol...any thoughts? do i just need to keep going down lower on the dial? bottom it out at 20a and see what happens?

Can you firmly attach a heatsink to the back side of the area to be welded? A copper or aluminum block clamped to the panel?

Expect some HAZ coloration, but this could be scrubbed afterwards

Just an idea anyway.

Oh, and welcome to the forum!

Trev

TRACKRANGER wrote:Can you firmly attach a heatsink to the back side of the area to be welded? A copper or aluminum block clamped to the panel?

Expect some HAZ coloration, but this could be scrubbed afterwards

Just an idea anyway.

Oh, and welcome to the forum!

Trev

mmmmmm that's true, i like that....i'll have to do some experiments, thanks!

I use aluminum for backing a lot when welding 304 SS. It works pretty well. You are going to have to pay close attention to dipping. If you miss a dip you may have a spot that burns through. Dipping cools the puddle, so a missed dip means that spot got hotter. It will show up more on SS than it does on mild steel.