Inner nose structure repair for 1977 firebird

Schroeder

Promoted Users
I have a few cracks in the 1977 firebird inner nose structure I'm working on. I don't have anything to gauge it against, but I think it's in pretty good shape. It seems to be kinda rough. I think it's a combination to age and deteriorating gel coat (if that's even in here) and flaking paint from over spray that hit this piece when a previous owner painted the outer urethane bumper cover.

The cracks are very tiny and are on very tiny features and tabs. Is the process the same as if this were a large crack in a fiberglass fender in that I grind a bevel in the crack and lay 3 layers of fiberglass down? What about the gel goat issue? Can't say I even know what a gel coat is. Do I need to spray or brush something on this after scuffing it up to restore that? At some point I'm finishing it in SPI white epoxy. Does there need to be a gel coat layer first?

I've picture the US Composites stuff I have to make sure it'll work. I've also pictured some tiny little plastic pieces that serve as quick nuts of sorts. You're supposed to screw right into them. They split, retain the screw, and in splitting open become too big to pull our of the hole they're placed in. Where can I get some of these?
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I believe that headlight panel is SMC fiberglass, it should be repaired with epoxy adhesive instead of standard fiberglass resin. You can use 3m 08219 or there are several other manufacturers that make it. SEM, Polyvance, Evercoat, etc… The white nylon bezel retainer nuts can be had from Classic Industries.
 

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Thanks for the replies guys. Today I noticed there is a tab that's broken off and missing. How do I reconstruct this? Do I mold it out of the 3M 08219? What do I use as the form? A piece of wax paper or tin foil?

Edit: holy crap! A tube of that 3M stuff is $73!!!! What are the cheaper alternatives? What's the evercoat, SEM, and polyvance part numbers you recommend?
 
You can use wax paper, aluminum foil as a backer. Apply the cloth and repair adhesive, once cured, remove the backer and then repeat the process the same way for that side.

SMC will be smooth on both front and back sides due to the type of compression molds used to make the part. The overall appearance of bare SMC looks like marble. Fiberglass will typically have a smooth and a course side, meaning you can see all the layup strands usually on the back.
 
You can use wax paper, aluminum foil as a backer. Apply the cloth and repair adhesive, once cured, remove the backer and then repeat the process the same way for that side.

SMC will be smooth on both front and back sides due to the type of compression molds used to make the part. The overall appearance of bare SMC looks like marble. Fiberglass will typically have a smooth and a course side, meaning you can see all the layup strands usually on the back.

Do you have the product list I should use if it's SMC? You've only mentioned general brands like evercoat. They have a lot of products. I might pick something that isn't the best option if you guys don't direct me.

I'll try figuring out whether it's SMC or just fiberglass. I know I have another one of these from a donor car. It's in perfect shape but it's sat outside for so long that the things hairy. There is no smoothness to it at all. It's a fuzzy, soft piece that needs gel coat or something. If I could restore the surface it'd be a perfect piece for selling. Its current surface finish made me think this this headlight bucket is a fiberglass piece.
 
Do you have the product list I should use if it's SMC? You've only mentioned general brands like evercoat. They have a lot of products. I might pick something that isn't the best option if you guys don't direct me.

I'll try figuring out whether it's SMC or just fiberglass. I know I have another one of these from a donor car. It's in perfect shape but it's sat outside for so long that the things hairy. There is no smoothness to it at all. It's a fuzzy, soft piece that needs gel coat or something. If I could restore the surface it'd be a perfect piece for selling. Its current surface finish made me think this this headlight bucket is a fiberglass piece.
You can restore it with epoxy primer. Just scuff it and shoot. No need for gel coat.
 
You can use Polyvance 2020-t, USC 77702, 3m 08219, or Evercoat 100864 to fabricate and repair the missing tab using fiberglass cloth. These products work on both SMC and fiberglass, standard polyester resin will only work on fiberglass.
As for the cracks, you can use a small drill to make a hole the end of the crack. This stop drill will keep the crack from progressing, v groove it out then fill it in.


You can restore it with epoxy primer. Just scuff it and shoot. No need for gel coat.

When you are done with the repairs, do as Don says above.
 
Here is one that was attempted to be repaired about 20 yrs ago with standard fiberglass and resin. I ripped it off in about 2.5 seconds like a band aid. This is like SMC
 

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Because now you really got me wanting to know what the heck this thing is made from, I went and dug out one of mine. On the back there is a “PP” and “B” code. Doing a quick internet search it comes up as “PP” Polypropylene, “B” glass fiber reinforced. Now with that info, I’m not sure how to go about fixing it. Epoxy repair material / SMC adhesives may or may not work. Try it and hope for the best.
 

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Did more digging, the TDS sheets for Polyvance 2020-t and 3m 08227 state they will work with polypropylene. They Polyvance are 2-5oz tubes for about $40. The 3m is the 200ml size for $63 both on Amazon.
I have a couple of these to repair as well, so was worth the research.
 
Did more digging, the TDS sheets for Polyvance 2020-t and 3m 08227 state they will work with polypropylene. They Polyvance are 2-5oz tubes for about $40. The 3m is the 200ml size for $63 both on Amazon.
I have a couple of these to repair as well, so was worth the research.
Wow thanks. I wouldn't have known that those markings were a clue. So much great knowledge here. So, you mentioned the 3M one before. I take it that's the one you use and recommend? If this stuff is epoxy I'm guessing it doesn't have much body and is gonna be a thick gravy texture. If this is more or less correct it'll ooze and flatten out. I plan on building a little form out of tin foil that's roughly the shape of the tab that I need to recreate. I'll fill the tin foil form up with the repair material and let it dry.

As far as prepping the base where it has to bond to do I just scuff it up with 80 grit?

EDIT: 3M 08219 is a version that will cure hard. Reviews for the 3M 08227 state that it will be flexible. Are any adhesion promoters required for this to work?
 
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I actually used 3m 08274 which was the 400ml version to fix a big truck tilt hood. No adhesion promoter was required for SMC/Fiberglass. 3m 08219 is the urethane version, you don’t want that.
I just reread the tech sheet for the Polyvance. They recommend using filler prep 1060FP and the flex filler epoxy 2000-t for polypropylene. I missed that the other day, so it sounds like both Polyvance and 3m are on the same page, using a flexible epoxy to repair polypropylene. To do that small tab and a few cracks you may be better off using the tubes of Polyvance 2000t. It will save you from having to get the applicator gun and static mixer nozzles that you need to use the 3m.
You can always call Polyvance and ask their recommendation just to be sure.
 
It does make sense that flexible repair is recommended though. Your shaker and trunk spoilers are SMC and those are very solid and would want a rigid filler. This headlight panel is definitely way more flexible than those.
 
It does make sense that flexible repair is recommended though. Your shaker and trunk spoilers are SMC and those are very solid and would want a rigid filler. This headlight panel is definitely way more flexible than those.
So use the 3M 08274 or polyvance 2000-T to construct the tab? If I go with polyvance I need adhesion promoter 1060FP? I'm getting confused with all the options.

Here are the things I still have on order.

Polyvance Plastic Magic (aerosol) https://a.co/d/ifYMgWz

Flex Filler 2 (tubes) https://a.co/d/8T47UGP

EDIT: I ordered the 1060FP too. I can return the 1050 adhesion promoter of it it's wrong. I can't find the 1060FP data sheet.
Filler Prep Adhesion Promoter https://a.co/d/7Nz1s2S
 
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I think you should be good to go. When you look on their website, the 1060FP is specifically called out to use when intending to repair Polypropylene parts. So use that and the filler. Don’t just glob it on, use a backer, foil or something similar and reconstruct the tab in layers. You can treat it like a fiberglass repair, using fiberglass cloth. You just use the epoxy filler instead of resin.
 
I think you should be good to go. When you look on their website, the 1060FP is specifically called out to use when intending to repair Polypropylene parts. So use that and the filler. Don’t just glob it on, use a backer, foil or something similar and reconstruct the tab in layers. You can treat it like a fiberglass repair, using fiberglass cloth. You just use the epoxy filler instead of resin.

Thanks for the help. I'll give it a go hopefully this week or weekend (if the stuff comes on time) and report back with some pics.
 
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