which welder?

[sclurgess]

hi ive been welding for a little while now and have got the hang of thin stuff but i recently tried welding to some box section but my welder just laughed and refused to penertrate it. so im wondering what kind of ampage i need to weld 3mm box section ?

thanks and great site. love the aston resto

 

[jolly_roger187]

What are you using at the mo? 3mm...... I've got a 150 turbo and it will eat straight through 3mm, if i let it! Are you working on cars, i'm sure you'll only ever need a 150 if you are, but dont quote me on that.

 

[malcolm]

What are you using at the mo? Are you working on cars, i'm sure you'll only ever need a 150 if you are, but dont quote me on that.

Sorry, couldn't resist doing the quote.

I've never quite been able to meet the welder manufacturer's claims for welding thick stuff. My 150 amp welder is supposed to do 6mm sheet, but I guess that would involve grinding the joint into a V shape. For welding a joint that hasn't been V'd mine would probably manage about 3mm max.

 

[sclurgess]

i think mine is only 100amp it was only a cheap jobbie

 

[malcolm]

The 100 amp welder would struggle with 3mm. Have you tried tapering the sides of the join? That reduces the effective thickness of the metal - at the end of the taper you'd maybe have 0.5mm steel, and by the time you've filled the V with weld you should have worked enough temperature up to melt a bit of the thicker metal.

Has anyone got one of those charts (often to be found printed on the side of a welder) suggesting what amps you'd need to weld different steel thicknesses?

 

[sclurgess]

oooo that rather handy. i remember that then thanks