Originally Posted by Dodosmike

Pics for comparison










Large washers were placed on the inside of the car (a '78) for the rivits to grab.

Originally Posted by rvzio

Hard to see the rivets and yes difficult to do but it can be done. For me I ma just trying to keep things as close to original as I can during these modern times. Just another way! They look like pop rivets but they are not.
RVZIO

Originally Posted by Domobomb

For the SMC vs not SMC. My car is a '78 SA.

I am going to use bolts. I don't care so much about what the factory did. Everything else is modified on the car; I intend to autocross.

I'm just trying to get the reproduction reinforcement bracket to fit nicely and line up with the old rivet holes, which it does not.

I was going to use 3/16 bolts because that's what fits. Will that be strong enough? Or should I drill them out and use 1/4"?

Originally Posted by DUB

From what I was told by a customer/friend who actually built the top hood surrounds for the 1975-1982 Corvettes. That the resin used in the process was not polyester based....thus...not the same as the earlier Corvettes....thus a different type of resin and adhesive is needed.



I did not work at molding plant. I worked at the Charlotte assembly plant building the trailers themselves. Which the only reason I mentioned it was due to I do a lot about using solid rivets and bucking them.



Any color of what??? You lost me on this.



If you are strictly commenting on the old archive photo of the assembly worker working on the Corvette underbody/rear tub area.

I agree. That era of Corvette is not SMC. But the original thread starter's Corvette is SMC.



An SMC panel is slick as glass on both sides and is a gray color often times with dark streaks running through it making it look like marble.

The panels from the earlier Corvettes are not as slick and actually will have a very, very light texture to them...and the fibers.... as like has been mentioned....are consistently different.

DUB

Originally Posted by Alan 71

Hi Jim,
While I saw a small assortment of rivet 'heads' used on my car, I think I saw only 2 different 'set' sides.
The most typical, and seemingly used everywhere, was the simple 'mushroom' set.
However, on the support strap for the spare tire tub, the rivets, while having the typical large flat head, have a very precise and consistent shape to the 'set' side.
????
Regards,
Alan




I'm curious about these?

Originally Posted by blade072

Another idea that might help would be to put a urethane adhesive between the reinforcement and the fiberglass underbody. That would make all the surfaces to nest together plus a good adhesion. Then you can rivet or bolt. Make sure you install large washers on the inside of the underbody. I would think that 3/16 would be fine, but for peace of mind, go to 1/4.

Originally Posted by DUB

with adding an adhesive....as long as the surfaces are prepped correctly for the adhesive to have any worth and actually adhere.

The size of fastener is up to you when you bolt the gusset to the body.

BUT what gives me more concern is the caged nut that the body bolt screwed into. I KNOW that GM used the caged square nut for 19 years.

But when I do repairs in this area...and the caging is rusted to pieces...and the nut was shot. When I go back in.... I cut a plate of steel that fits in the bottom of this #4 mount area on the inside....then I add large washer...and then a lock washer and nut. This is so when I get it all tight....that square plate I fitted to the inside of this area is now covering the entire bottom surface area.....and NOT just the surface that the original square nut covered.

DUB

Originally Posted by Domobomb

Thanks Dub,

Yeah, the cage and nut came out in pieces so I plan on just using a bolt like you say.

What's the best way to prep the surface for the adhesive?

I appreciate it. Thanks.