Whats your thoughts on butt welding two sheets of 5'x12' together to make a bottom for a skiff? Bottom thickness is .190 aka 3/16 5052. I have checked with my local steel/alum supplier and he said twelve foot was the longest sheet he could get. I would have to have the twenty foot sheets shipped in which I would prefer however I would like to build me a skiff sometime in the next couple months. The five by twelve sheets of .190 cost $400 per piece.

try to find a diffrent aluminum supplier cause we get 20 foot sheets down here in louisiana all the time cause it cost more to get a cut sheet!!!

Aluminum & Stainless or Pierce Aluminum

Both have places in New Orleans and Broussard

he is in indiana, not la

It's not ideal, being it's going to take more time and attention to keep everything fair, but any aluminum boat over twenty feet is going to have a seam weld, so it's no big deal if done right. We use to seem those 5x12 sheets together all the time on 12' decked over air boat hulls and never had that center seem fail. I've welded on many 100'+ aluminum crew boats and there made of many sheets welded together

Mandel metals in Chicago carries a wide range of material and will have 20 footers

Thanks a bunch guys. I really appreciate your input.

X2 I don't see a problem with it at all especially on 3/16. Get good penetration and you will be fine

Out of curiosity, would you chamfer the ends of the sheet before welding to help with penetration? Or just weld flat end to flat end?

For what he's doing I would bevel the edges and leave a small gap between the sheets

X2. Just be careful when buffing the weld not to dip into the sheet.

It's gonna b hard to keep the weld seam from getting distorted, or dog legging.

On .188" material I wouldn't bother with beveling the edges. I would leave a .188 gap and use a .188 backer plate. The backer plate will help with some of the distortion.

Mag 10

Im having to pay 2.50 per pound here locally. I called Mandel in Chicago and it was 1.87 per pound. They had one twenty foot 3/16 in stock however no idea of when they will have more. I am going to call Tals buddy at Pearce and see what I can come up with.
Thanks for the replys.

K Im not sure. Tal said he could hook me up.

"Would the backer plate be used structurally? Or just to avoid weld splatter?"

It is somewhat structural. It is used to focus the depostion between the components that you are trying to join. The weld nugget will tie the 2 sheets and the backer stip together instead of letting the energy just blow through the gap and thus bettering the posibility of a complete joint penetraion. Because you are adding a strip of material you are creating a "backbone" along that joint that can help with distortion along the length of the weld.

Mag10