Jeep Cherokee floor pans

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Hello all. Getting ready to undertake my first  big project. Going to be welding in floor pans into my Jeep Cherokee. Kind of torn on a few things.First off I'm going to be using a Hh140, 30 MIG wire with c25 gas. Pretty standard set up I think. Also I'm using pre fabbed floor panels so fitment should be a huge issue. I'm sure I'll run into something though.Where I'm getting fuzzy is whether or not to gap my butt joints or try to fit them as snug as possible. Also whether or not to just spot weld it every 1-2" and seam seal the rest or try to go until I have a continuous weld. I know I need to jump around so as to not heat the metal too much.  For the gapping I was going to pick up some of those clamps from harbor freight. I have been practicing and I'm having a tougher time with gapped metal. Although I don't have proper clamps yet so that could be some of my issue. Penetration definitely isn't an issue here and I have gotten to where I really never blow through. Any words if wisdom? Sent from my SCH-I545 using Tapatalk
Reply:I'd recommend 0.023 wire and the less gap the better. Any points where the floor gets welded on top of say a support bracket, use a zinc-based coating (that can be welded through) between the floor and the bracket - helps to prevent rust in that area.
Reply:Yes, a weld through primer would be a good idea on overlapping joints. A copper spoon can be a big help with slight gaps if you have an issue. If it were me, it would be close fitbutt joints, or a full overlap, approx 1 inch. Either stitch weld it on the edges, or get a spot weld punch, and punch holes for spot welds every 3-6 inches. Spray the ovelaps with weld primer, and be sure to use clamps to keep the sheets pressed together when you weld them up.Good luck!
Reply:I thought about the .023 wire. May still go that route I would just have to buy a new roller and possibly liner for the welder. I need to check the part number on the one it came with. I didn't think about the weld through coating. What would I be looking for there name brands wise? And I guess I don't understand the copper spoon trick?Also I've been going over in my head how to clamp this if I go with no gap or over lap. There are places there is no way I can see to use a clamp.Sent from my SCH-I545 using Tapatalk
Reply:The copper spoon is a nice addition. It does 3 main things. One, its a great heat sink for small spot welds. Its a great backer and shield for gaps to decrease contamination. And they can make great makeshift "prybars" to use to hold something down when you tack it in place.The weld through primer can often be found at NAPA stores, no specific name brand. It is essentially a galvanizing coating, that prevents rust. Just use proper ventilation. If you cant get a welding clamp/sheet metal clamp in there, just use self tapping screws. Zip them back out later, and plug weld the holes.
Reply:I've used this - 3m Weld-Thru Coating II stuff before http://www.amazon.com/3M-05917-Weld-...dp/B0015PG4E0/ - it's pretty good but also expensive. there are other brands that will work just as well... look for 'weld through primer' or 'cold-galvanizing spray' with a very high zinc content.
Reply:Ok. Thanks guys. I'm going to try going the overlap route. Not sure how it all will fit since the new panels are pre fabbed but I guess I'll find out. All I need for my welder is the drive roller and typos the liner is fine for the .023 wire. Thanks for the help. It will be a couple weeks but I'll post updates here when I get it all started.Sent from my SCH-I545 using Tapatalk
Reply:All I use is .030 in my little mig. If you had .023 that would probably be better, but I wouldn't buy a lot of stuff for .023 if I had.030.Tim Beeker.