In my effort to eliminate the rivet blisters on my `68, removal of the surround reinforcement is necessary. My understanding of a cross-section of this area would show the layered construction to be, from the top: fiberglass, bonding agent, rivet head, bonding strip, bonding agent and metal reinforcement. If that is the proper sequence then removal of the reinforcement is accomplished by separating the surround and the reinforcement by wedging the two apart? I wouldn't have to be concerned with rivet heads in the glass? I understand that the blisters were caused by the corrosive reaction between the aluminum rivet and the steel reinforcement forcing the rivet out, so I'm assuming that the glass is deformed in that sequence. Is my thinking correct? I've searched the archives and found some helpful info but nothing that addresses this layered build sequence. There's nothing in the AIM concerning the reinforcement at all. Comments and remarks will be appreciated.
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Re: `68 Headlight Reinforcement Bond/Construction
Your sequence is correct except that there is no bonding agent between the bonding strip and the metal bar. The bond here is typically very strong and difficult to separate without damage to the surround panel. Some people just cut out plugs over each rivet and clean out the junk, then repair the holes. That will work, but it is very difficult to keep the tale tale signs of the holes from shrinking and showing later. -
Add-on....
If you don't fully remove the already oxidized aluminum rivets, you can expect the 'bulges' to return after a drill-out/fill repair exercise as the oxidation process that's already started will continue.... Next, if you use simple bond to fill the holes, you can expect just what Wayne said -- shrinkage over time and visibility of the fill repairs. However, if you do the fill job RIGHT by using fiberglass vs. bond to plug the holes, the repair should be satisfactory for the long haul.Comment
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Re: Add-on....
Thanks Guys. I fully intend to do the job right and will use use mat & resin for the fill. I'm hesitant to start prying there but to do this job once is my goal. Would you know the diameter of the rivet head and would you recommend removing all of the rivet or just past the head? There's thirty-five of those suckers!! They missed one. Thanks again.Comment
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They are about a half inch across the tops. It should be OK to remove the head entirely down to the stem. If you are very industrious you could remove the whole thing and replace them, but you run the risk of the same problem in about twenty years.Comment
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Re: Add-on....
Thanks Wayne. I think my plan of attack will be to drill through the rivet stem from the bottom. This will give me a center point to drill off the head. Then I'll chamfer the hole, lay in filler, mat and resin and finish appropriately. Any foreseeable problem? I've checked the reinforcement/surround bond and it appears really secure all the way around with no voids. I really appreciate the suggestions and information. Thanks.Comment
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Re: Add-on....
The only problem is that there is no bond between the bar and the bonding strip. If you remove all of the rivets this way, there will be nothing really holding the assembly in. In that case I would replace the rivets, or at least some of them. If you can see the bumps clearly, I think that a 3/4" hole saw would be sufficient to get to the heads from the top.Comment
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Good point Wayne. I've stripped the paint from the nose and upon really close examination there are only about a dozen blisters. Using a straight edge and light I can find no deformation from other rivets so, using your suggestions I'll repair what damage I can find or what I perceive as damage and throw myself on the mercy of the Corvette gods. Then in another 30+ years, I'll re-examine. Thanks again for the info.Comment
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Re: Add-on....
Hey David,I just replaced my header bar support on my 69 last fall. I actually removed the bonding strip from the the hood surround because one side was coming loose and it wasn't that bad of a job(easy to say now that it's done though;) ) Anyways before I riveted the steel bar to the bonding strip I placed about a 1/4 inch length of heat shrink tubing over the shank. This I hope will help to eliminate the disimilar metal corrosion between the aluminum and steel. After the rivet tail was formed,the excess heat shrink tubing easily pulled away and left no evidence at all of being there...so it looks good too. I also brushed the rivet head and the area where it will be in contact on the bonding strip with bonding adhesive to prevent moisture from getting to it. With these to additional tasks I'm pretty sure that disimilar metal corrosion and moisture/air related corrosion to the shank and especially the head will be a problem that this car will never see again. Just something for you to think about.Comment
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Re: Add-on....
Hey Greg. I appreciate you looking in. In my research for this I followed your work in the archives and gained a better understanding of the work involved. In considering all the options and since my reinforcement bar is securely bonded to the surround, I'll probably attack the offending and near offending rivets from the top. Thanks for the information.Comment
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