i am prepping my body for paint and am wondering what the best procedure is to repair rust in gutter area? mostly surface type bubbles in a few areas.someone previously had filled the entire gutter with a 1/4 inch layer of bondo.is this a normal practice?or should inside gutter be clean painted steel.what steel prep chemical is best to coat rust areas/then prime with?? tks.ian
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Re: birdcage rust
Ian,
Where is the "gutter area" you are talking about?
As a general comment, the birdcage is a important structural component in your car, and body filler serves no purpose where you need strength. It will only make it look sound, and maybe help keep the rain out.
Chuck Sangerhausen -
Re: birdcage rust
The rust is very common to the mid-year coupe. The "body filler" you mention is what I believe to be a factory installed substance that is the root of the rust problem. Once moisture gets in the gutter under the factory sealer, it sits and rusts. To my knowledge no one repros this piece as I had to manufacture a replacement for an entire side on a 64 I fixed 4 years ago. A friend bought an entire center body section at Bloomington just for the gutters. I now have a 43K mile 65 and it has a little rust there. My experience has been it is very common Don H.Comment
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Re: birdcage rust
Ian,
OK, now I understand; you are refering to the top of windshield frame. I thought you might be, but I wasn't for sure.
If your car has never been repaired before, the material in the top windshield frame is a sealing compound as Don said; in my car, the "gutter" was almost completely filled with a gray sealing compound except for a black foam rubber seal under the front edge of the T-top molding. The sealing compound was still pliable.
In the top of the windshield frame, my birdcage ('70) has no rust, but I do have rust in the lower corners.
This is my plan: Where the corrosion is extensive with fair size holes (2 sq in), I plan to cut out the rusted area, and MIG weld formed sheet steel to repair the damage. In other areas, where there is light pitting corrosion with 1-2 small holes, I plan to weld the holes shut and not worry about the surface corrosion. I then plan to beadblast as much of the birdcage as I can by masking off the fiberglass, and then prime the entire windshield frame and lower birdcage area with 2 coats of PPG DP90 black epoxy primer. I then plan to apply top coats of zinc chromate primer to cover (mostly for original appearance. Yeah, I know, none of it show anyway).
Your corrosion doesn't sound too bad; If you just have surface pitting with no holes, I believe I would just beadblast it to white metal and prime it. If you have holes after beadblasting, you may be looking at some of the unattractive options that Don mentioned. If you have small isolated holes, you can probably get by without repair. If you have several inches of hole along the frame, you may need to replace the frame because cutting and welding in that area will be tricky.
Chuck SangerhausenComment
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Re: birdcage rust
Ian-----
It's very important to mention certain pertinent information in your posts in order that others might be best able to assist you. One of these "pertinent" pieces of information is the year Corvette that you are referring to. In your case, given your e-mail address, I assume that you are talking about a 63 coupe. For 63-67 Corvettes, all of the windshield frame sections have been GM-discontinued for years. At the current time, they are not being reproduced. However, in the near or not-so-near future, they may be. I understand that CSC Reproductions of Ohio is working on just this project. However, their first priority is the 68-82 Corvettes since the market is MUCH larger. For 68-82 models, CSC has had available the top windshield header bar and corner pieces for well over a year now. Soon to be available are the side frame and/or pillar posts.In Appreciation of John HinckleyComment
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Re: birdcage rust
I have 65 coupe and the upper right windshield frame portion of the birdcage is rusted and it extends down the forward post. I located the top off a 67 coupe and am having it installed on my 65. The work of cutting and replacing is quite extensive and beyond my expertise so a body shop here in the Sacramento area that specializes in Corvette body work is replacing the top of my birdcage assy. You may want to look into this option. The cost is around $1500 but all things considered I think it is worth the cost to have a professionl do the work and get the car back right. Feel free to e-mail if you want more info. Regards and good luck.Comment
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Re: birdcage questions
the birdcage rust in my 63 is only superficial, and appears to be mainly in gutter u channel that was filled with what seemed to be bondo.after bead blasting i will fill any roughness and prime. i was wondering if i should apply rust mort to the area and refill gutter with bondo as factory did? looking in 63aim book i can't see where the factory would have used a compound to fill gutter?? thanks for your great input guys!ianComment
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Re: birdcage questions
Ian,
I have never heard of "rust mort", but I'm thinking it's probably a product like Eastwood's "Oxysolv" (dissolves iron oxide leaving a zinc phosphate coating).
My opinion would be, if you can beadblast the surface to white metal, and apply a good epoxy primer, you wouldn't need anything more. If you can't remove all visual traces of rust, maybe it wouldn't be a bad idea. Regarding bondo versus sealing compound, I am in a poor position to help you since your '63 is a few years away from my '70. The mid-year guys would have to help you on that.
One thing you could try, is to look in your AIM in section UPC1. I doubt the organization of the AIM changed much from year to year. In my '70 AIM, the illustration of the upper windshield frame sealing is in UPC 1, Sheet F11. If you can find the illustration of the "gutter" area, you will see some little labels that identify the material with a "drop" icon and a number. Go to the front of the AIM and there will be a table (UPC 0 for me) several pages long that describes all sealers, lubricants, etc. used in the construction of the car. Look for the number you found in the little tag with the drop icon.
Chuck SangerhausenComment
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