Quick urgent question, thick to thin metal.

[t3gav]

Hi guys, I've read a few posts after searching but still a bit confused, I need to weld some 3mm sheet to 1mm sheet, the 3mm is on top of the 1mm (lap joint). I understand I need to concentrate the heat onto the thicker piece and drag it to the thin piece but I'm confused about torch work angle. Is it best to weld directly from above and flick the pool across or should the welder be at a 60 degree angle from vertical aiming at the corner of the 2 pieces but more toward the thicker steel?

Previous posts show the torch aiming at the parent metal but angled toward the top metal but surely this will blow through no? Appreciate a quick reply if pos, want to get cracking tomorrow

 

[BrokenBiker]

ah the same sort of job I am currently doing.

I fin the torch angle is fine at 45 degrees as normal, and weld as a normal lap but focus the puddle on the thicker metal. when I have done it the puddle draws over the thinner material anyway so you just need to concentrate on speed and looking for a hole starting to appear.

im sure someone more experience than me will come along shortly with the correct answer, but this works for me. I tried stiching it but it took ages and didn't give a very nice looking weld

 

[t3gav]

Thanks mate, it was this thread that confused me http://www.mig-welding.co.uk/forum/threads/welding-thick-metal-to-thin-sheet.31201/ the pic Wozzaaah posted show the torch aiming at the thin metal.

 

[t3gav]

Any other thoughts guys?

 

[BrokenBiker]

I have tried the way wozzah shows and it does work, the welds look better but I did find it harder. as for strength and penetration I couldn't see much between them but as I say the ones wozzah suggest do look neater and more profesional

 

[gaz1]

try this thread
some vids on there may help out better when you see it done

http://www.mig-welding.co.uk/forum/threads/lap-joint-3mm-on-8mm.44630/#post-494457

 

[Ricki.B]

Any other thoughts guys?

With is that thinner material if possible turn the job so u can quickly wash down vertically just my opinion