welding sheet metal

[towscum]

any tips, drill holes to weld? what size? how many? please help.  

[69*F5*SE]

Do you have your trunk floor extentions that go on each side of the trunk floor which attach to the bottom of the quarterpanel, the wheelwell and the trunk pan?  I didn't see any.  

Anyhoo, with the trunk pan in place using a silver Sharpie marker, crawl underneath and trace your frame rails and supports so that you know where to drill your holes for plug welding.  Pull the pan out once you've traced everything underneath, flip it over upside down to drill your holes.  Measure the width of the flanges of the framerails, supports etc. and split the difference and drill in the middle.  All in all, about 3/8" in from your markings.   Your best bet is using a "step" drill bit for a clean burr free top side.  Drill the holes about 2 1/2" to 3" apart.  As far as what size to drill, I've heard from 5/16" to 3/8" in diameter so maybe someone will chime in with a desired diameter.  Ofcourse no welding will take place till you've fit everything together correctly.  This should give you something to go by for now.  I tried. Ted

Someone else will chime in soon with instructions that may be different or similar.  

[green69rt]

 

I used 1/4 inch holes and it worked fine.  Larger is not necessarily better.  AFter all the holes are drilled I put the floor back in and marked through the holes onto the frame with a sharpie.  Then cleaned the frame and the underside of the pan.  Then I  painted over them with about 3 coats of weld-through primer.  I then drilled a few more small holes through the pan and frame so that I could screw the pan down to the frame to hold it tightly in place while I welded it.  When done just remove the screws and tack the holes closed with the welder and you're there!  As for the welder I use a 140 Hobart with gas and .025 wire.  I set the wire speed at about 35 and the gas at about 20-22 cfh.  Just my 

[towscum]

cool, thanks so much, that helped alot, now i know where to start ill post up some pics of my progress.