Best approach for welding this setup

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I'm sure this is realtively easy for most, but I consider myself still a newbie, but getting a lot better with welding!  Thanks to many  here!!Using MIG I am replacing a floorpan in my 73 beetle..Half of it gets bolted in, so that is no prob,the other half does get welding in.The new floopan is 22 gauge steel and its lip will be laying on part of the backbone of the tunnel which is much thicker than the pan, 10-14 Gauge -( not sure until I cut to it).  They have to be welded together.SO I am beleiveing that high heat necessary to melt the thicker metal will burn a hole through the floorpan, if it is directly exposed to the gun.I guess I will  have to heat the thicker metal enough to puddle and let the puddle "run into" and melt the thinner metal?Is this the proper approach?Any suggestions?Thanks!Matt
Reply:Use the same setup that you would use for 22 guage or just a touch more. Start the puddle on the thicker metal just a bit to the side of the 22 ga. Let puddle grow just big enough to blend into the 22 ga and start moving. You might like making a tight weave or small circles from the thicker to the 22. You just need to tie it into the 14 ga you don't need complete penetration of the 14 ga. It will actually be easier than lap jointing 2 pieces of 22 ga. Practice on simular metal before welding on the VW.
Reply:Thanks , that sounds good..I will practice on similar thickness of metalsMatt
Reply:I am familiar with the job you are doing. After fully removing the old pan, grind the entire tunnel lip, (it is actually made up of two pieces of approx. 12ga.) where the new pan will rest. Drill 3/8'" holes in the new pan to correspond approx with the same number of spot welds that held the original pan in place. Clean the paint and any rough edges from around these holes (both side of the pan) bolt in place, and fill the holes, use the roof (pad the top) and a simple jack to push the pan down tightly. Sometimes it's in and out with the pan a couple of times before you are ready to weld. The slower you go, the better the job.Just my  opinion, not from a book, just from the road.Howes Welding Inc.www.howesweldinginc.com