Floor Pans... Getting screwed?

[Mark Maras]

A quick question about floor pan installation. On the tunnel & rear side of the floor pan, what does everyone do, butt-weld or over-lap the welded seams? If they are over-lapped, I think it would be a good idea to weld the out-side solid to prevent rust. Thoughts?

[Patcon]

I used a small air powered body saw and a die grinder with a cut off wheel. Take zip screws and screw the floor pan where you want it. cut a section so the old panel and the new panel are cut at the same time. Butt weld that section then work around the panel skipping from side to side and end to end. This also allowed me to take a hammer and dolly and work the edges of the pan so they matched the transmission tunnel shape. After a little grinding and some primer the repair is invisible.

[240260280z]

I used a small air powered body saw and a die grinder with a cut off wheel. Take zip screws and screw the floor pan where you want it. cut a section so the old panel and the new panel are cut at the same time. Butt weld that section then work around the panel skipping from side to side and end to end. This also allowed me to take a hammer and dolly and work the edges of the pan so they matched the transmission tunnel shape. After a little grinding and some primer the repair is invisible.

 

 

Charles you are genius!  That is the best method I have ever read!   So clever and efficient!

Edited October 25, 2015 by Blue

[Mark Maras]

Thanks, that sounds great. I really didn't think the over-lap method was the best option. Guess I wanted to hear it from some one that had been down this road before.

 Harbor Freight sells sheet metal welding clamps (8 pack) that I will use for aligning the edges. They worked great for aligning the footwell insert that I welded in. That one I carefully cut & fit. It turned out good but it took a lot longer than I estimated. Doesn't everything? I wasn't looking forward to precisely fitting the floor pan prior to welding. There had to be a better way.

 I'm working on the right side only at this time. When it's done, I'll take a look at the left. It has to be better than the right. No battery. I didn't want to be overwhelmed at the size of the project. Kind of like eating an elephant-you can only do it one bite at a time.

[Patcon]

I can't take credit for that. I have the Kevin Tetz videos and that is how he recommends fitting panels. Rough cut them, then overlay and screw in place then when you finish cut them they are the perfect size and ready to weld in

[wheee!]

I was going to do the same thing basically with cleco fasteners. Butt welds are best! Seamless repairs....

 

Edited October 25, 2015 by wheee!

[Patcon]

I don't own any Clecos but they would work. The 1/4" zip screws like heating and air contractors use work great, are cheap, no predrilling and you end up with a small hole to fill either way. I use a magnetic 1/4" bit holder so it can be set with one hand, leaving the other hand free for panel placement. For what a few Clecos cost you could buy several hundred zip screws and the bit holder.

[wheee!]

True. I have both so maybe I will experiment!

[wheee!]

Yeah, that section of welding the new frame to the old frame under the car is tricky. You can make it a little less upsidedown by jacking up just one side of the car. The 240Z floors go in MUCH easier than 280Z floors. I installed 280Z floors/frames in my race car over the winter and it was tough even with a helper and having the car on a rotisserie!

Chuck

 

Wow.... I'm almost at that stage now... It looks like you left the seat rails in place, cut underneath them, then tacked the floors in from the bottom with a slight overlap. Then welded thru from the inside thru weld holes, then spot welded around from the bottom. I assume you then seam sealed or did you do a complete seam weld?

I was almost thinking of doing a butt weld for the whole pan but that seems a little overkill for this job; too much risk of warpage etc. Thanks for the pics and ideas!

 

I am still torn about doing the zip cut butt weld method too though.... arrggghhh!

Edited December 18, 2015 by wheee!

[cbuczesk]

I probably did a complete seam weld. I think that I then used some filler to eliminate then edge so debris wouldn't catch it.

 

I'm currently working on my AAR 'cuda and am replacing part of the floor pan. I'm going to lap weld because the metal is thin. Years from now I'll put it on the rotisserie and do a more complete/better job.

 

Chuck

[Patcon]

Butt weld. Do it right the first time and forget it.

plus like Chuck said no edge to collect debris...

[madkaw]

Butt weld would make the job a lot harder and prone to mistakes of over cutting. It also makes welding more of a challenge. No one will see it, so I would go the easiest route and lap weld. It's easier to secure in place for welding also.

I plug welded my floors in place holding everything together with clecos. Then I welded seams .