Just got a nice quick question. Need to fix up the couple holes in the floor pan atm.

Now i attempted with the MIG, and it just created a huge mess and burned extra holes. I messed around with power/heat levels and wire feed still with no fix. Im just wanting a nice easy weld like normally welding mild steel with minimal grinding to get a decent finish.

I have also attempted braising and a high intense solder with no decent finish.

Would it be worthwhile to just borrow a mates TIG for the job or is their any tip's/tricks im missing out on.

That or im a spastic, and instead of welding it just tack over and over.

With thin metal you should have a heat sink behind when you are welding... I use a piece of copper but ally works just as well... If you are cutting a piece out and replacing with new stell you shouldn't be burning many holes but if you are trying to fix honey comb rust holes you will blow them away... Heat sink is the answer to welding thin steel ;)

Quote:

You sir, are a genius.

Now i feel like a retard for not thinking of it in the first place :(

Another thing to try - was suggested to me when experiencing similar issues. And that is the thickness of the mig wire. I was using 0.9mm, and apparently, the 0.6mm being thinner, carries less current (albeit marginally) and will actually create less heat on similar settings, and be less likely to blow holes, or at least not as severely.

Heat sink definiitely works. Maybe try both? I actually managed to weld a nut to a timing case (on an aussie hemi 6 if anyone cares, to make a cam thrust end stop) - which would normally warp and be useless with an oxy, but I managed it with a block of copper and sat the timing case on it.

If you are really mad keen - I reckon it's probably possible with some mig welders out there to modify them so their lower, or lowest setting is lower than they come from the factory, specifically for very thin metalwork like that. I think I've read about it on another forum. IIRC it was on a forum dedicated to woodwork (no kidding, and I know that sounds 'wrong') - where they were discussing various tweaks to fix weak/inconsistent wire feed motors and transformers on some of the home user level mig welders out there.

0.6mm wire I also swapped to afterwards... It does make a big difference :)

The welding class wurzel and I took, the teacher was obviously a long time qualified welder dude and building a hot rod...... With a wooden chasis lol.... So woodwork forum and welding, nothing supprises me.

I also said were his welds that bad he had to build it out of wood

Another variable is the shield gas. Straight CO2 raises the arc voltage slightly and penetrates deeper, not something you want when welding thin sheet metal.

75/25 argon/CO2 penetrates less than straight CO2, produces smoother welds and spatters less but does not tolerate dirty/rusty surfaces.