MIG Aluminum- Warp control on long flat sheets?

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I have 5 sheets of 1/4" diamond plate, dimensions 48" x 72", riveted to a flatbed frame back to back. They are already mounted, have a 1/8" 45 degree bevel, butted against each other. Rivets are spaced across the entire bed, but I'm still worried about distortion since it has to be spray transfer. Preheating seems impractical due to the sheer size of the sheets, so the current plan is 4" beads scattered evenly across the bed. Any thoughts?
Reply:I don't bother doing 4inch welds scattered weld it in long as possible welds just back step when doing it
Reply:Your drawing is not clear as to 'where?' these partial bevel groove welds will be.The better you can pose the question, the more appropriate the answers can be.Amen to back stepping the welds and working sequentially from the outer edges towards thecenter (if there is a 'center').For long diamond plate weld seams requiring no structural strength per se, just simplysealing or closing a seam edge (which may be your example as well)..........I've run a bead 3-6" stop, water spray cool immediately, air blow off and continue.AL sheet distorts from heat input and allowing this heat to build up and spread asthe welding progresses.Removing this heat immediately--stops distortion.One needs to have the weld parameters dialed in for min. heat input and AL MIG isa low heat input method.Blackbird
Reply:Leave about an 1-8 inch gap so the sheets can pull together. If there is no room for expansion you will end up with several large buckles in the sheets.Miller xmt304,  Miller S22 p12, Miier Maxstar SD, Miller 252 w 30A, Miller super32p12, Lincoln Ranger 9, Thermal Arc 181I with spoolgun, Hypertherm 10000 ,Smith torches. Esab 161lts miniarc.