I'm nearly finished on the panel gaps and intend to attack the front and rear end caps on my coupe. It's apparent I'll need to build up the bodyline on the end caps after I take off the twenty million coats of whatever from the previous owner. What is the best filler to bond to pot-metal? I'm looking for something that has excellent adhesion, and hardens sufficiently to minimize chipping and dings. I'll need to add at least an 1/8"-3/16" of filler across the top to get a nice line to the body panel.

 

BTW, I saw the "Bondo" thread from last week and understand the epoxy-filler-epoxy discussion dealing with filler and moisture. My question primarily deals with the pot-metal end caps and the best filler for that material. I intend to have all four end caps sand blasted and epoxied before I start.

 

Check out 3M 8115. You will need a special applicator gun to mix the product in the tip. It would be a good idea to bolt the spoiler extensions in with about 80% effort so you don't lose all of the bonding adhesive between the parts.

When the adhesive dries, be sure to sand down any that has squeezed out of the cracks and cover with more epoxy and then continue your filler work.




LORD also makes great bonding products, different mixtures for fg to fg, steel to fg, etc. so be sure to purchase the correct product. Depending on where you live, the 3M might be easier to source.

You want to use a quality reinforced filler such as U-Pol SMC to fill and smooth after the parts have cured.

 

i'm assuming your still making the quarter extension removable and you don't need a product like a panel bond adhesive.

3/16" seems like quite a bit even for the poorly fitting factory parts like the extension. can you shift it upward so you won't have to add so much filler? or does that cause issues with the trunk lid? if you could compromise between the two and add a little less filler, then i think you could go with pretty much any lightweight filler you like (excluding BONDO brand) with little to no concern.

 

Agreed, even if you need to elongate the mounting holes to get the part closer, I would for sure try for a better physical fit before I filled that much.

For what it is worth, I think any good filler will stick the the extensions quite well so long as you have an 80 or 36 tooth. 3/16 or more on the edges might be prone to some issue with chipping, but if I had to do it I would.

 

I completely understand, my problem is the prev owner or bodyshop sanded the top edges and now they're too "rounded". I need to build that edge back up. I'm avoiding purchasing new end caps because I've been disappointed with several of the after market parts. In this case I'd rather fix the original or purchase original from a bone yard.

 

If you need the edge on the endcaps I would place a piece of waxpaper on the car then use the filler on the endcap then press it into place, secure it and let it harden up. I would do the body line while on the car then remove and shape it for a perfect radius. A quality filler will work fine.

 

i wouldnt blast the caps....just coat them with some aircraft stripper... it will make quick work of getting the paint gone...then put a good 80 grit tooth on the surface so the epoxy has something to bite into...

 

I have a pair for cheap if you want them. See here...
https://mustangforums.com/forum/clas...s-already.html

 

EZFeed, I just dropped you an email, let's talk.