but joining sheet metal

[Psychosaffa]

is it possible to but join 1.5mm / 2mm sheet metal without it deforming with a mig?

i want to join 2 x 2.5m x 1.25m sheets of steel, but i need it to look like a single complete sheet when done.

 

[Jan]

As a beginner I would think it's possible, but would take some serious technique to make the joint look like a single sheet of the same thickness. The only way I could do it would be by welding from the 'wrong side' and with both sheets flat on the work bench. With such thin metals there would be a lot of deformation as the heat soaks into the work pieces unless some of it was carried away by a heat sink on the good side. A series of tack welds at 100mm intervals followed by adding extra welds to each in turn should help. It would be tedious, but if the correct finish was achieved it would be worth the effort.

 

[hotrodder]

Welds shrink, there's no way round this and while heat sinks can minimize it/keep it localised i can't think of many things more difficult than joining two full sheets together and ending up with an invisible joint. Which way are you wanting to join 'em? Sheet metal is available in a far wider range of sizes than the usual choices of 2000x1000 and 2500x1250 and can also be cut to length off the coil for example... http://www.steelexpress.co.uk/structuralsteel/sheets.html#CR4

 

[BrokenBiker]

i wouldn't bother trying, it will warp and bend all over the place with the welds cooling and contracting. Its not too bad on car body work as its usually not flat stuff and has other sides holding it in shape, but even then you have to take measures not to put too much heat in