"Early" 1966 Grill Supports GM # 3875777

[David L.]

According to my 1966 AIM and my 1966 Chevrolet Parts Catalog (effective Oct. 1965) the part number for the "early" 1966 grill supports is 3875777. According to the revision record in the AIM GM # 3875777 was replaced with GM # 3897389 on 12/03/1965. Enclosed is a couple of photos of a pair of NOS 3897389 supports that are stamped with the letter "W" (the manufacturer, I assume). I removed the white GM part number stickers to clean off a few areas of very mild light surface rust.

Two questions:

1. What is the difference between the 3875777 and 3897389 supports?

2. What are others doing to keep NOS supports from rusting? Before I installed NOS supports on my NOS 66-67 grill with 4 NOS 9418482 rivets during my 1966 restoration (1980 to 1995) I painted the supports with a "natural metal" paint.

Dave

[John H.]

Re: "Early" 1966 Grill Supports GM # 3875777

2. What are others doing to keep NOS supports from rusting?

Dave -

Those supports were flow-coated at St. Louis with semi-gloss black primer before they were riveted to the grille.

[Ronald L.]

Re: "Early" 1966 Grill Supports GM # 3875777

Dave, another mis queue for the latest 6 JG?

[Brian K.]

Re: "Early" 1966 Grill Supports GM # 3875777

John, any difference with AO Smith built cars?

[David L.]

Re: "Early" 1966 Grill Supports GM # 3875777

Dave -

Those supports were flow-coated at St. Louis with semi-gloss black primer before they were riveted to the grille.

John,

What do you mean by "flow-coated"? Is this the same as "dipped"?

Dave

[Ronald L.]

Re: "Early" 1966 Grill Supports GM # 3875777

Davis, Basically yes. The flo-cote systems used back then had a pre wash, phos "etch' which then gave the basis for the paint to stick and then went into the paint bath, and then into a bake. Its not the same as taking a can of solvent based enamel or lacquer and dipping the part into it and then letting it dry. The solvents were different.

[Scott S.]

Re: "Early" 1966 Grill Supports GM # 3875777

Dave -

Those supports were flow-coated at St. Louis with semi-gloss black primer before they were riveted to the grille.

For parts that were originally dip-primed or flow-coated, can anyone explain how to (re)paint these parts to end up with a typical factory production appearance?

[Ronald L.]

Re: "Early" 1966 Grill Supports GM # 3875777

Scott,
Pay to have them done by a production shop, what I mean there is an OE shop, some are close by me so in bulk this is a really easy option, or... I've been thinking about this one (its on the list of things to do). You do want to get that run look an rattle can paints etc just don't do that.

[John H.]

Re: "Early" 1966 Grill Supports GM # 3875777

John, any difference with AO Smith built cars?

Nope - A.O. Smith installed the four brackets riveted on the inner fenders those supports attached to, but the supports themselves were installed at St. Louis with the grille, right after Body Drop.

[John H.]

Re: "Early" 1966 Grill Supports GM # 3875777

For parts that were originally dip-primed or flow-coated, can anyone explain how to (re)paint these parts to end up with a typical factory production appearance?

Scott -

Don't over-think this - they were painted in the same system as all the other loose brackets underhood and under the car; just shoot them with semi-gloss black and don't worry about runs.

[John H.]

Re: "Early" 1966 Grill Supports GM # 3875777

John,

What do you mean by "flow-coated"? Is this the same as "dipped"?

Dave

Dave -

St. Louis had a "Flow-Coat" prime system for wheels and small metal parts - from my Assembly Process paper:

"
Wheels, radiator supports, and the hundreds of smaller steel and iron parts (brackets, reinforcements and engine dress components) were processed in the main passenger/truck plant and delivered from there to the Corvette plant in various sizes of racks and containers for use on the line. There was no raw-metal prime or paint facility in the Corvette plant other than the small crude zinc chromate primer system in the basement used for the birdcage.

Wheels and most metal parts were received raw and oiled from their suppliers, and were processed through a 6-stage hot degreasing/wash/rinse system, followed by iron phosphating and a chromate rinse. Then they went through a flow-coat booth where they were deluged with a semi-gloss black primer from many nozzles like showerheads on all sides; excess primer dripped off the parts through floor grates into a sump tank and was recirculated again, and the parts were baked for 45 minutes at 325*F."

[David L.]

Re: "Early" 1966 Grill Supports GM # 3875777

What about the "early" 3875777 supports? Does anyone have an original one?

[Scott S.]

Re: "Early" 1966 Grill Supports GM # 3875777

Scott -

Don't over-think this - they were painted in the same system as all the other loose brackets underhood and under the car; just shoot them with semi-gloss black and don't worry about runs.

I don't have a lot of experience with paint, as my next question is about to reveal. About the many small parts that were originally dip-primed or flow-coated, why couldn't they be literally dipped (submerged) in a gallon sized can of black paint, semi or gloss as appropriate for the part, and then allowed to hang or drip-dry from hooks?

Seems like it would be faster and easier than spray-cans, and might also end up looking more like typical factory production. Is there some reason why this wouldn't be a good idea?

[Ronald L.]

Re: "Early" 1966 Grill Supports GM # 3875777

Scott,
Hardware store paint is not the same. These flo-cote paints were not exactly water based but pretty close. I don't see that you can take rattle can or a quart of rustyoleum dilute it and get the same result. It might get close enough for where these are located though. You'd want to bake out the finish too and that's tricky with the solvents involved.