I have gotten conflicting recommendations on what to use to bond the Headlight Support to the body? Will this same material work for the fender to the lower support? Also what is the best filler to use to level out low spots on the body?
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Re: 73 Roadster Fiberglass Work
Most suppliers who sell body panels also sell bonding adhesive. Unless you are using the grey SMC panels GM sold as late service parts, most any polyester base adhesive will be fine.
Good ole pink bondo is the best body filler in my book.
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Re: 73 Roadster Fiberglass Work
Thanks for the info. The panels are original - I think- they are grey. This old car took a hit sometime in its life and I am tring to bring it back. I had heard that there were different adhesives based on when it was shipped. I just don't want to make a mistake! Thanks again. BobComment
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Re: 73 Roadster Fiberglass Work
Bob, I think the light gray with occasional black streak is SMC, where polyester fiberglass is dark charcoal (black) with visible glass fiber sworls. My 70 has several original panels which I believe to be SMC including the door skins and the T-top skins.
Several modern adhesives can be used with SMC; Lord fusor comes to mind, but body shop supply stores should know what you need. These adhesives are probably more expensive than the polyester adhesives, but they do have the advantage of working with either type of fiberglass...polyester based adhesives can only be used with polyester fiberglass.Comment
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Re: 73 Roadster Fiberglass Work
Thank you Chuck, you cleared up the confusion. I thought it was SMC, and I really appreciated knowing the 'good adheasive' can be used on both. Even a 'major' supplier of fiberglass parts had confusing info. After struggling with up to 4 different colors of paint to remove, I am finally starting to fix things and put it back together.Comment
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Re: 73 Roadster Fiberglass Work
The 73 was probably the first to use real SMC and that was on some front end parts like the hood surround panel. Other parts could have been a mixture of types. Some parts are the intermediate material known as Gennite and some were even old polyester parts. For instance the rear deck panel was the last piece to change over to the modern materials and most are old polyester. The door panels on later 69s were the first to change over. Some of those may have had polyester on one side and Gennite on the other. Each year afterwards showed a steady procession of change over until 74 when all major panels were of the new materials.Comment
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Re: 73 Roadster Fiberglass Work
Wayne, Gennite must be what my 70 has on the doors and T-tops. If that is true, then what is Gennite and what type adhesives are used? Can polyester adhesives be used or do you have to use the SMC adhesives?Comment
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Re: 73 Roadster Fiberglass Work
Genite was a product of General Tire Co. It was a low shrink resin that solved most of the surface problems of the polyester panels. General became a major supplier of parts after 68 as a result of its use. You can easily tell the difference between it and the old polyester panels. It has a much smother surface and a characteristic light gray color. I am not a chemist or an expert on the difference between it an SMC, but from experence it is easier to bond than SMC. The factory still used what appears to be a polyester bonding product even into the SMC era, but it is different from the material used previously. The bond was adequate, but not great. This is evidenced by the massive splitting of seams and separation when a late C3 is wrecked. They will litterally explode into their component parts. I would suggest using a modern epoxy based product to bond them. However there are some products on the market that are recomended that are polyester based.Comment
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Re: 73 Roadster Fiberglass Work
I've used epoxy adhesive to reconstuct a C2 front clip using the GM SMC replacment parts. This stuff is great and will bond everthing (including metal)
Epoxy offers about pot life of 45 minutes to an hour versus 10 minutes for the polyester based adhesives. The extra time is HUGE advanage to ensure proper alignment before it kicks.
The disavantage to the stuff I used is that it was Purple in color. They may have the correct shade of charcoal with today's materials.
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Re: 73 Roadster Fiberglass Work
Tracy thanks for the additional info. I have used West products on a sailboat. It is an epoxy product. Perhaps I should use this to bond the headlight support to the surround and the lower corner of the lft front fender to the birdcage.Comment
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Re: 73 Roadster Fiberglass Work
Bob,
Epoxy adhesive is great stuff, but not intended to be used as a substitute for factory assembly practice.
In both applications you've mentioned, there should be a fiberglass bonding strip that is riveted to the birdcage and the headlight support with flat head aluminum rivets.
If these pieces are not present, I would advise that you get them riveted on before bonding the parts together.
Your Assembly Instruction Manual (AIM) should detail the attachment locations.
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