Rivets working up through glass on nose

[Paul S.]

Re: Rivets working up through glass on nose

I Know A Way To Fix This Problem So It Will Not Ever Come Back. Sometimes It Can Be Done Without Repainting .For Your Own Sake , Don't Go Grinding or Drilling Into The Outside Of The Surround Panel , You Are Only Asking For Problems (i.e. Filler Shrinkage) I've Done Several Over The Years I Can Explain How ,( It Takes Too Long To Explain And I Can't Type For Sh*t). If Someone Wants To Call Me ,please Do: 330 537 3585 ( Nights)
Paul

[Mike G.]

Re: Rivets working up through glass on nose

remove the rivets and use the bonding adheasive instead or they will re appear in time.

[Kenneth B.]

Re: Rivets working up through glass on nose

Prior to body-off restoration, body man, showed me bumps in the nose just below the hood line. He indicated this was from rivets working up from below. He drilled-out the holes re-filled them, new gelcoat, new paint. Approximately 2 months after new paint was applied, the bumps re-appeared. They were drilled-out again, filled with glass, new gel coat and new paint. Body man is saying other painters are indicating this problem is likely to resurface. Does anyone have experience with this condition?

Maby I got lucky. my LT-1 coupe with original paint has no bumps & is from southern Mich. LT-1 conv. one & a 1/2 repaint no bumps. 454 conv one repaint no bumps all 3 cars Feb/ March build dates. I wonder if process was changed or I just got lucky. The 2 repaints are 10 & 2 years ago.
KEN

[Joe L.]

Re: Rivets working up through glass on nose

Come to think of it, I don't think I've ever seen an early original C3 that didn't have the nose pimples. I expect to see them on these cars.

Jeff-----


I have an original owner 1969. It has absolutely no trace of the rivet "bumps" and has never been repaired. I have a friend who is the original owner of his 1969 and his has absolutely no trace of the "bumps" either.

I believe that the root cause of the "bumps" is corrosion of the aluminum rivets. As the aluminum oxide is created in the corrosion process, its volume is greater than the original aluminum metal converted to oxide. So, it has to have "somewhere to go" and this creates the "bump".

I further believe that the cause of this corrosion is salt applied to the roads in winter in certain states. My car and the car of my friend have lived in California all their lives and have been exposed to no road salt.

[Harmon C.]

Re: Rivets working up through glass on nose

It is a lot of "fun" John. After removing the bar, you have to grind the fiberglass in the area that the bar is to be bonded to. To give it an authentic look, I removed the heads of new rivets and bonded the shanks in the old header bar. You need to peen the shanks so that they appear to be correctly installed. Remove any paint on the top of the header bar. I use Lord Fusor to bond the bar to the upper surround. Make you a jig to clamp the bar at least overnight. Then you can repair the holes in the panel either using fiberglass or using panel adhesive to fill them

This is the way I make this repair. I glass in the holes the same as I do with all those rear deck luggage rack holes. I leave my cars set in the sun after glassing up holes and think it helps stop later shrinking. My shop is small so letting cars set in the sun happens often. I have my body man finish all the places I glass up. If finished right the spots never show up as some of my paint work is ten years old and no problems yet.

[Clem Z.]

Re: Rivets working up through glass on nose

It is a lot of "fun" John. After removing the bar, you have to grind the fiberglass in the area that the bar is to be bonded to. To give it an authentic look, I removed the heads of new rivets and bonded the shanks in the old header bar. You need to peen the shanks so that they appear to be correctly installed. Remove any paint on the top of the header bar. I use Lord Fusor to bond the bar to the upper surround. Make you a jig to clamp the bar at least overnight. Then you can repair the holes in the panel either using fiberglass or using panel adhesive to fill them

does not sound NCRS "correct" to me without the "bumps"

[Jack H.]

Re: Rivets working up through glass on nose

Just being a California car, doesn't guarantee lack of exposure to salt water... Cars that spent time near the ocean (salt air) or those that went to the mountains in the winter (Tahoe, Mamouth, Etc.) can exhibit salt water induced oxidation.

[Jack H.]

Re: Rivets working up through glass on nose

I remember a very low mileage 1970-72 car that came for Bowtie judging at Sun Valley. It had something like 1300 miles on the clock and had spent its life primarily indoors (original belts, original hoses, original oil filter, original oil!). There were no visible header bar rivet 'bumps' in the front end.

So my conclusion is early C3 cars without evidence of oxidation deterioration in this area ARE, in fact, 'NCRS cars'...

[Richard L.]

Re: Rivets working up through glass on nose

I just bought a California-Colorado 71 coupe. The bumps are barely visible, so I surmise that the lack of corrosion (galvanic action/reaction) between the steel bar and the aluminum rivets is the correct answer as many have stated. In order to prevent the dreaded bump condition, I'm thinking of spraying the steel bar with AEROKROIL. Supposedly this liquid will keep rust at bay for a long long time. Any opinions or past experience in this regard?

[Joe L.]

Re: Rivets working up through glass on nose

I just bought a California-Colorado 71 coupe. The bumps are barely visible, so I surmise that the lack of corrosion (galvanic action/reaction) between the steel bar and the aluminum rivets is the correct answer as many have stated. In order to prevent the dreaded bump condition, I'm thinking of spraying the steel bar with AEROKROIL. Supposedly this liquid will keep rust at bay for a long long time. Any opinions or past experience in this regard?

Richard------


I don't think applying the Aerokroil will do any harm although it's not beyond the realm of possibility that the carrier solvent might soak into the fiberglass surrounding the steel reinforcement. However, I doubt that the Aerokroil will do much good, either. Once this type of corrosion begins, it will, unfortunately, proceed inexorably.

By the way, many years ago there was an excellent article in Vette Magazine describing the rather involved process to repair the problems caused by the aluminum rivet corrosion in this area. The article was written by Ralph Eckler, the fiberglass expert that was once a contributing editor to Vette Magazine. That would be an excellent article for the NCRS Restorer to re-print if the copyright could be obtained. Otherwise, it would be a great article for Vette Magazine to re-publish.

[Richard L.]

Re: Rivets working up through glass on nose

Joe-
I'll wait for more responses before I proceed. I don't mind if my hypothesis doesn't work, however I sure don't want to make matters worse! It's possible that others may have tried it and I'd like to know their results.

[Joe L.]

Re: Rivets working up through glass on nose

Joe-
I'll wait for more responses before I proceed. I don't mind if my hypothesis doesn't work, however I sure don't want to make matters worse! It's possible that others may have tried it and I'd like to know their results.

Richard-----


Yes, hearing from folks that have actually tried the method you suggest or some similar method would be the best way to determine the efficacy of it. The only problem is that it's very difficult for anyone to really assess just how well the method did or didn't work since the corrosion process is so slow it would be hard to quantify.

[Wayne W.]

Re: Rivets working up through glass on nose

Part of the problem with the later cars is the shape of the bar. It is a V shape with the point down. This will retain more moisture than the midyears, which seldom have the problem. They are made of the same materials. Many, probably most, C3 cars never develop the problem, but those that have seen a lot of moisture or salt conditions do.

As for why they stopped using the rivets and bonding strips, I think that was mainly because in 73 the surround panel was changed to SMC, and bonding them required an epoxy type material which also work well with the steel bar. It also saved some money for the part.

[Joe L.]

Re: Rivets working up through glass on nose

Many, probably most, C3 cars never develop the problem, but those that have seen a lot of moisture or salt conditions do.

Wayne------


Yes, my 1969 original-owner, always-in-California car has never developed even a hint of the problem.

[Kenneth B.]

Re: Rivets working up through glass on nose

Come to think of it, I don't think I've ever seen an early original C3 that didn't have the nose pimples. I expect to see them on these cars.

MY 1970 19000 mi LT-1 Coupe with original paint has no bumps at all. Corvette came from Howell MI. in 1979 & has been in IN. ever since. I also had a 72 ZR-1 that had original paint with no bumps. Most of the others had some lifting. I wonder if some times some rivets got coated some how?
KEN