Cleco Fasteners and Plug Welding

cmfisher4

cmfisher4

Promoted Users
I'm going to be replacing floors and sills on my TR4 and want to try cleco fasteners this time around. I've never used them, but they look like a much better solution than sheet metal screws. I'm just curious about their use.

Do I use the clecos as a precursor to my plug welds? In other words, should I drill cleco holes (and buy right-sized clecos) that match what I'm going to use for my plug welds (1/4-ish) and use that existing hole for my plug welds after pulling the cleco?

Or should I use them as just an attachment point, using 1/8" ones and then put the plug weld holes where I want them (like right next to the cleco so the panels are tightly joined there)? I would then go back and fill in any of the 1/8" holes as necessary.

Now that I type it out, I figure the first solution is not effective because I would lose the clamping force of the cleco if I pull it to then weld it. Given that, what size clecos would you recommend buying?

Thanks,
Chris
 
Clecos aren't used that way. What they are for is for temporary clamping of a replacement panel over the original panel. Then the location of the panel is scribed on the original panel and then the original panel is trimmed to the scribe mark. The clecos are removed and the panel then butt welded and the cleco holes are welded up.
Plug welds are generally only done to replace factory spot welds. Plug welds are usually only done on flanges.

What are you trying to do? I'll try and help if I can. :)
 
I'll add that the use of clecos are not very common in the auto body/restoration trade. They are used mainly by metalshapers for fitting hand formed panels. They are widely used in the aviation industry for replacing aluminum panels. They rivet panels in aviation so the clecoes work well clamping a lap joint. Then the cleco holes get riveted. That is what they were originally designed to be used for.
I guess that you could use them for clamping say a 1/4 panel, but their clamping force is a fraction of what a vise grip type clamp or even sheet metal screws would be.
 
Hey Chris, thanks a lot for the extended replies. Your second response is what I'm trying to do. I have a floor and a two-piece quarter panel that all get welded together. I want to be able to get them all aligned, temporarily, to make sure gaps and all of that are good as I make my repair. I figured clecos would be more convenient for that, and while welding stuff together. The repair panels are complete and are not required to be cut except for minor fitment adjustments.
I used the sheet metal screws and vise grips for the Spitfire, just was wondering if clecos would be better. Seems like it'll be a wash at best.

Thanks!

Chris
 
Hi Chris, Sorry a bit late to your show... check out this video from a high-end e-type coach builder guy. He attaches panels with sheet metal screws and then fills the small 1/8" hole followed by the 1/4" flange hole to make a strong plug weld.

Monocoque Metalworks

Around the 1:30 mark or so...
 
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