I just received 71 vette from parents in florida. It has been sitting at least 12 years in the humid salty air. Mostly a lot of rusted suspension parts. My main concern is when looking at the car from the side. There are several "bumps" between the lights and hood that seem to be coming from under the paint/fiberglass. I am assuming, as there are many rusted parts under car, whatever is under body there must be rusting... so the question is whats is under there???

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Someday!

Not fully sure about this, but if the bumps you're referring to go along the seperation between fron bumper and main body, my understanding is that these are caused by the original rivets(?) rusting. I've heard it before and those members more involved in restoration do know how to make them dissapear/what they mean.

Scot

Those are the original aluminum rivets that hold the fiberglass body skin to the metal header support. They are beginning to corrode, and that causes the circular bumps you can notice.

Hey, thanks for the info, but does that mean i have to remove body from frame to fix??


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Someday!

I have read from others who have tackled this problem, two ways to remedy. One is to dish the area of fiberglass by grinding and fill area back up to level. Other is two remove body from rivets and re-bond with adhesive material in lieu of rivets. I personally have left the bumps as this indicates that the body has never been altered from factory (including paint in my case) assembly. Many of these older 1st generation sharks (1968-1972) also have the bonding seams showing thru the paint on each of the 4 fenders (also an indication of originality).

The other alternative is to live with it and enjoy your chrome bumper beauty. I see lots of Corvettes with this problem and it seems that most of us live with it. Kind of like wrinkles when you get older - you earned them.


Gary

I had the chance to work on the paint on a 72 that had this problem also. As stated above it is corrosion on the rivets that hold the glass to the body. If you grind it down and re-glass it, it should come back because you haven't treated the corrosion. I used a 3M Imperial Hand Glase on the paint and it didn't stand out as much when the car was finished. The color of the car was gold. When the owner picked it up, he decided not to have it fixed (he was going to have the front clip replaced). He was that happy with the difference that it made. Keep this in mind, if you know Corvettes, this is something that just happens. It is like acne when you are a teen.

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Hilton 67 |URL|http://www.vettefinders.com/79Registry/car_images/Upload79.JPG|/URL|

As the others have replied these are the rivets rusting and pushing up and deforming the fiberglass... IT IS A VERY COMMON PROBLEM.... start looking at C3's and you will see these "bumps" on a lot of them...

I did this "fix" on my 76 5-6 years ago...It involved removing the entire metal brace and replacing it with a
new brace... then installing the new brace. then doing the body work to the nose of the car to remove the bumps...

The replacement brace itself was purchased new for under 50 bucks. not a problem... BUT removing the original brace is a royal pain..slow work because the original is glued on..

which means you have to take a chisel and gently un-glue it from the fiberglass... I ended up making a few 18 inch or so chisels out of bar stock to allow me to reach the brace in some areas... Replacing the brace is just a matter of appling glue and bolting it in before the glue sets... lol) I did not use any damn rivets however !

Anyway.... it was not difficult...only a slow process
the expense came with the body work on the nose then repainting... which was something I was planning to do anyway...


Hope this helps a little

Bob Griffiths

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Bob
64,72 & 98 Corvette Ragtops
76 & 79 & qa 88 ANC Corvette Coupes

Click on any image for larger view!

I am restoring my '69 right now and ran into the same dilemma. My painter has done several of these in the past. Basically a section of 'glass is removed to expose the rivet heads. The rivets are drilled out. All metal components prepped and cleaned up. New rivets installed and fiberglass rebonded into place.

not the best close up shot but you get the idea.



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Jeff Jatich

My 68 has the same scenario, I asked the head-curator at the Vette Museum what he thought about hoesawing each one out and putting in steel rivets, as the originals are aluminum and he said any NCRS judge would automatically deduct points for a non-original front clip. Not that that matters to me, because it does look out-of-place. The problem is the front body support is steel and the original rivets are aluminum, and what happens over the year is called galvanic corrision. Dissimilar metals react to the salt, moisture, etc. and the reaction is what causes the dimples along the front upper support. Ever try to get an aluminum rim off from a steel rotor or brake drum? I'm leaving mine alone as proof of the original front-clip. Good luck Phil

I am in the process of setting up some time to do an inspection on a car in the southeast, and I was told by the seller that this car has this raised rivet issue which tells me that it is an unhit (at least in the front) body. My question to all of you is this. Just were do I look for these bumps? Is it down the middle of the the front end between the headlight doors where the flags emblem is? The seeler said he would point them out once I get to see the car.

I'm beginning to wonder what some of you are seeing. The front end is riveted in 2 places actually. First, there is a re-inforcing strip at the nose directly behind the bumper. It's riveted through the glass with what I call a "smash rivet". You're supposed to see those, but they are hidden behind the bumper. This type of rivet was used all over the car, but most are out of site. If you see a "pop" rivet there, it's been repaired.
The other place rivets were used is the header bar. It runs along the front of the hood opening. With the hood open, you can see it. The way this was attached was with a bonding strip riveted to the header bar and the bonding strip adhered to the surround panel. There are a couple of scenarios in which the rivets may "telegraph" through the surround, I can't say I've ever seen a corrosion problem there, but I do understand the dissimilar metals issue.
I've seen some ameteur jobs where the bonding strip was eliminated and the header bonded directly to the surround panel, sometimes riveted through the surround. It's not a pretty site. I've also seen rivets and screws used in collision repair and left in place then simply either glassed over, or worst case, covered with bondo. These kinds of repairs tend to show themselves very soon after the car is painted.
Back to the header panel, this bonding strip is almost a quarter inch thick and the rivets are recessed into it some. I would think they would have to be corroded pretty bad to push through the surround. Keep in mind they are what is holding the header bar in place. The header bar gives the forward portion of the surround it's shape, it's a reinforcement piece.
I hope this helps, I'd hate to see someone here buy a car that's been misrepresented.

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A quick question, I assume that to remove this piece I have to grind each piece of rivet sticking through the metal strip???

Ron

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Someday!

Ruready2go said: A quick question, I assume that to remove this piece I have to grind each piece of rivet sticking through the metal strip??? Ron

I'm assuming you want to remove the strip from underneath. That's going to mean removing everything that's attached to it. Kind of a lengthy process with the body still on the car. Let's see if we can come up with a simpler way to fix this. A few questions;
Is the header bar rusty?
Has the 'glass delaminated anywhere in this area?
Can you e mail or post o good picture of the "bumps" I'd like to see this as closely as possible. If you may have longer term plans to do a total resto, maybe we can come up with a way to repair the problem without a major disassembly.
Any other body people out there want to look at this again too?

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Thanks but I thing I got it... Yes the bar is rusty, but the main reason Im taking it off is the rivets/bumps coming through on the glass (on the other side). I do already have engine out, lights out (in process of rebuilding them), so I have very clear look at under side. I acutally just finished cutting the underside rivets off with air hammer and high speed cutter. Now Im getting ready to "ease" off the bar. I hope!... I take some pics and post later tonight..

Thanks!!!

Well just got the metal piece off pretty ease, but bigger question...how do you get the bonding strip off the expose the rivets from underneath???

|UPDATED|10/31/2004 4:24:45 PM (AZT)|/UPDATED|


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Someday!

To separate the strip from the surround, drive a sharp, stiff puty knife or something like a painters tool (5 in 1). Dont use something as stiff as a wood chisel. I've also used a kitchen knife, go very slowly and try not to go through the surround above it. It's very thin and will damage easily. Start at one end, fron and back.
Let us know how it comes off, you will have to prep it before re-installing. There's also a real good chance you'll damage the surround, not the end of the world, but it too will need to be properly repaired.
Let me know how you make out.

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after removing the header metal bar by grinding the rivets from underneath---chisel off the bonding strip (after marking the position exactly)---clean the bonding strip of cut alum rivets and glue --- reinstall a new header metal to the bonding strip (use original holes) you will need about 40 large head alum rivets (from dr rebuild or other supplier)--i made a rivet set tool from an old air hammer bit by cutting it off and drilling the end slightly--once you have assembled the header bar-bonding strip --glue it to the surround in the exact location it came from (it locates the headlamps)--i used the same bonding adhesive that holds the fenders together--its a lot of work but its the right way to do it

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|COLOR=RED| |/COLOR||IMG|https://www.c3vr.com/member_uploads/2201_2300/2262/sigbanner.jpg |IMG|

You may want to remember, the adhesives that were available when our cars were new are not nearly as good as some of the materials out there now.

The Lumina MiniVan uses a steel space frame and has fiberglass panels glued to the frame with an special epoxy adhesive. The stuff is amazing.

Yes I do recommend the rivits, but the newer epoxies will hold just as well, if not better. Why not use both?

There's also a poly urethane out. Most body shop supply houses carry it. It's the kind that mixes in the tube. The guns aren't cheap, I have seen this stuff used to glue a steel panel on a car as opposed to welding. Like Ken says, some of this new stuff is far superior to the old bonding adhesives which weren't much more than glorified bondo.
If you want to go more conventional though, Evercoat makes a decent adhesive.

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When putting bonding strip to header bar. Do you just put rivits in place and "smash" end of rivit to mushroom it over to hold the strip in place?

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Someday!

Ruready2go said: When putting bonding strip to header bar. Do you just put rivits in place and "smash" end of rivit to mushroom it over to hold the strip in place?

Basically, yes. Thinking about it though, it might be a good idea to put an adhesive on it as well, a bit of overkill, but you're going this far............

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Ok, I've tried about every tool I have and I can't seperate the bonding strip from the shroud. It seems very brittle and if I use something to stiff it just crumbles. Im to the point of just grinding around the entire thing and having to buy a new one...so the question is when others tried the above suggestions ie knife, chisel was it that hard to seperate the two???

Thanks, Ron

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Someday!

Nothing about panel removal on a vette is easy, especially if you're trying to save the part. Your issue is compounded by the location.
Patience grasshopper!

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I must not have by brain in gear because I am not following what you are having problems with...

I made my own chisel when I removed the metal brace

made it out of a 18 inch long piece of bar stock...
pretty thin at the end and increasing in thickness very slowely to about 1/4 inch... then just used plenty of light taps...along the edges of the brace..

Bob

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Bob
64,72 & 98 Corvette Ragtops
76 & 79 & qa 88 ANC Corvette Coupes

Click on any image for larger view!

The "brace" or header bar came off pretty easy. Im trying to get the bonding strip that the header bar was on. Under the bonding strip are the rivits that attached the header bar to the bonding strip to the cowl. What has happened, which im am told is common, is that the rivits corroded and the only way they could go was up through the fiberglass which makes small bumps between the hood opening and the light openings all across the length of the cowl. I was easily distracted today because of "other" things I wanted to take off and clean and paint. So soon I will stop procrastinating and get to it...

I have much to learn master Dave, signed grasshopper!

|UPDATED|11/14/2004 6:34:48 PM (AZT)|/UPDATED|


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Someday!

Well young (not really) grasshopper was very impatiet today master Dave. So he use air power die cutter, and air hammer with chisel bit to obliterate fiberglass bonding strip to million pieces. Me learn valuble lesson about small pieces of fiberglass and skin. On plus side master, me wife rub cortisone all over body to soothe skin...

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Someday!

That glass smarts. OW! It usually stings for a few days.

I now getting ready to fix this before putting engine back in car. My question is, looking under at metal brace that is glued on...I think this is listed in catalogs as header bar, metal...but what is the bonding strip listed with it?? I need to remove this metal strip and the reinforcement behind bumber because of rust..pandora's box is now offically open!!

Thanks, Ron

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Someday!

The bonding strip goes between the steel header bar and the surround panel. It rivets to the steel header bar and glues to the surround panel.
The nose re-inforcement simply rivets to the front leading edge right behind the bumper.

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As Bob states above that he just glued it back on and did not use rivets again, would I still need the bonding strip...?

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Someday!

Ruready2go said: As Bob states above that he just glued it back on and did not use rivets again, would I still need the bonding strip...?

I'm pretty much convinced the factory did things like that for a reason, Bonding steel to Fiberglass isn't a good idea mostly due to differences in thermal expansion, if the 2 different parts expand at a different rate, the bond will eventually fail. By riveting the bonding strip to the header, it is allowed to move and flex some, the bonding strip in essence becomes part of the surround panel (secondary bond).
I honestly could not recommend eliminating the strip.

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