Were 67 bodies primered and da sanded before paint from the factory?

[King M.]

I have my 67 body down to bare fiberglass. I found a grey primer under the lacquer and under the grey was a red primer and then bare fiberglass. On the rear of the car where the bonding strip is between the fender panels, there is a slight depression, I am curious as to whether the factory would have used a high build primer over the rear bonding strips and da sanded it smooth? I don't remember the depressions or dips before. Can someone identify the different primers as well? This is an a.o. Smith body.

thanks

king

[Wayne W.]

Re: Were 67 bodies primered and da sanded before paint from the factory?

The seams should have been prepared with body filler before primer. I have never seen any special high build primer to finish out the seam. The primer for 67 would have been red oxide with some gray sealer in various coverages and then the lacquer paint.

[King M.]

Re: Were 67 bodies primered and da sanded before paint from the factory?

Did the gray sealer seal the fiberglass or the red oxide primer? So all bonding strips were sanded smooth with filler and then grey sealer or red oxide primer was paled on top?

[Tom K.]

Re: Were 67 bodies primered and da sanded before paint from the factory?

King, I attended a paint seminar at the KC national last summer held by Tom Ames, the Corvette paint expert. I have a 67 that has been down to bare glass in some spots and the same red primer and gray primer/sealer in others along with some of the original red paint. Tom said that the seams always shrink and that he puts more resin and glass mat over those areas to build them back up, then sands them down. He then sprays the entire car with Eckler's sprayable gel coat over the bare glass to seal any stray fibers and to stop and future paint issues. It was a fantastic seminar and Tom is a great guy and very helpful. Hope this helps.
Tom K

[Tracy C.]

Re: Were 67 bodies primered and da sanded before paint from the factory?

The purpose of sealer is to seal the primer. It minimizes the amount sanding scratches that show up in the primer following the primers exposure to the lacquer thinner mixed in the paint. They still show up with a coat of sealer, but not as bad.

[Duke W.]

Re: Were 67 bodies primered and da sanded before paint from the factory?

Tom said that the seams always shrink and that he puts more resin and glass mat over those areas to build them back up, then sands them down.

Very common, but I question whether it's due to "shrinkage". The gaps between the body panels/bonding strips were filled with "bond" - the same concoction used to bond the panels to the bonding strips - and then sanded down. I think it was the sanding operation that left many a little low.

I made my own bond with polyester resin and finely ground fiberglass to build the seams back up. We're probably not talking more than 10-20 thou.

Beginning in about the mid-seventies something changed. and it's more common to see not just slight depressions, but seam lines on this vintage than earlier models.

Duke

[Domenic T.]

Re: Were 67 bodies primered and da sanded before paint from the factory?

In my past 50 years I can say that ALL non shrinkable fillers, primers and glass, shrinks. No such thing as non shrinkable. Any where that one panel meets another will shrink. A formed panel without a seam will eventually change shape.
Glass is great, won't rust but does not hold it's age without a wrinkle, kinda like us!!

Dom

[Jack M.]

Re: Were 67 bodies primered and da sanded before paint from the factory?

FYI- Here is the paint process listed in September 1965... I doubt it changed much for 1967.

Hope this helps,
Jack

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Corvette Exterior Paint Process

PRIMARY SANDING - All body panels and bonded joints that received acrylic lacquer are dry sanded to prepare surfaces for painting. A filler material (called putty rub) is applied to the entire body to fill minor imperfections. PRIMER - Two coats of primer are applied (the first red and the second gray) and are oven baked for 60 minutes at 280 degrees F. WET SANDING - The body is wet sanded to provide a smooth surface for the sealers. Most of the gray primer coat is removed with the red primer acting as a depth signal for the sanding operation. The body is dried to remove all moisture. SEALER - One coat of sealer and one coat of color acrylic lacquer are applied and baked. DRY SANDING - The body is dry sanded to prepare surfaces for the final acrylic lacquer. LACQUERING - Three coats of acrylic lacquer are sprayed on the body to build up the required paint thickness. The paint is "rested" for eight minutes to permit it to partially set up and to remove excess volatile paint vehicle. INITIAL BAKING - The body is oven baked for 30 minutes at 140 degrees F to harden the paint which permits the subsequent operation. Small interior and exterior parts are painted to complete the body paint schedule. FINAL BAKING - To assure a durable, hard, high luster finish the lacquer is oven baked for 45 minutes at 250 degrees F. Reheating the lacquer permits the paint film to soften and allows surface blemishes and sanding scratches to disappear during the thermo-reflow process. FINAL SANDING AND POLISHING - The body is lightly oil sanded and polished to bring painted surfaces to a high luster finish

Chevrolet Engineering Center - September 1965