GM Heritage Center Documentation / Underbody color

[NoYenko]

JohnZ you never seize to amaze me with your knowledge & memory. There it is noted on page 453. I heard your pretty involved in NCRS, do you know if the Corvette guys are using the GM restoration paint, or how they feel about it?

[DavidS]

So John, do you know what the color of the bottom of the Camaro should be and what was this color made of?  And what was the color of the primer that was sprayed by hand that overspryed under the car?  Was this color more pronounced on LOS cars vs. NOR cars because of the height on the lines?

Hopefully John can answer this and of course John would know much better than I would.

but going by the GM instructions, comments, and pictures of the cars posted, here is my conjecture:

step 2 - black primer and in vulnerable areas a black compound like Hammerite is applied by hand

step 4 - the entire body is painted in gray primer. Again, applied by hand.  Since in a NOR car the underbody is only 18" off the ground and not easily accessible, areas that recieved gray primer were inconsistent.  I have no idea about a LOS car but I would think they could easily end up with a lot more gray primer.

I started out believing that underbodies were supposed to be gray primer color and right now I believe they are mostly black with some sections that have gray primer.

[JohnZ]

JohnZ you never seize to amaze me with your knowledge & memory. There it is noted on page 453. I heard your pretty involved in NCRS, do you know if the Corvette guys are using the GM restoration paint, or how they feel about it?

I don't recall the primer colors, although Van Nuys probably used a different formulation due to their environmental restrictions.

The GM Restoration paint (black) really didn't have much application on the Corvette, as the only black used on the body (other than exterior black) was the underhood blackout on the firewall, inner fenders, and underside of the hood; it was a flattened cheap black lacquer, sprayed after the final bake oven, which air-dried. On the exterior, Corvette used red oxide primer, then gray primer, then sealer, then color lacquer, and there was no paint of any kind on the underbody - just raw fiberglass.

[DavidS]

I wonder if color pictures exist showing the underside on either the NOR or LOS assembly lines.

In John's terrific write-up, he has these two pictures:

#1
   

#2
   

#3    GM has this picture which is similar to picture #1 - Van Nyes (LOS) assembly line for 67 Camaros
   

has anyone ever seen a color picture that is similar to picture #2 ?

[Steve Shauger]

The underbodies on most of the original cars I've looked out are primarily (90%) black as the last "primer" and then have body color overspray over the black to varying degrees. Usually the upper areas such as over the axle and the tunnel areas have more grey primer, rather than black. That's typically what I have seen but in a few cases I have seen primarily grey primer on the lower areas and black primer in the tunnel and overaxle areas. What I recommend is closely examining the car prior to resto, document your findings with pictures and replicate what you have found during the restoration. The pics NOYENKO posted is typical of what I have seen and serve as a good reference.

[Steve Shauger]

Heres a couple of pics. Ironically a few pics are from a Yenko we certified a few years ago.

[Steve Shauger]

I believe the photos I posted show the grey primer was applied first and then the black . The black in most cases did not cover the "hard to reach upper areas" such as upper tunnel, over axle and lower firewall.

[DavidS]

Great pictures Steve! 

It would be great if what the pictures show could be matched against the GM instructions.  Is it possible that the gray primer in step 4 went on over black primer in step 2?

[firstgenaddict]

The drop offs and rear rails extensions are gray as well.
04C Norwood

[Hans L]

Pictures of my '69 Van Nuys 04B underside as well as the factory green firewall - go figure.   Whatever the paint material was (primar or paint), the underside was clearly black throughout with significant body color overspray.  The car is an original SoCal car - never spending anytime outside of the area.  I found no signs of non-factory undercoating anywhere. 

Regarding the green firewall - my only guess is they ran out of black paint that day and dark green was the closest alternative. 

[firstgenaddict]

Pictures of my '69 Van Nuys 04B underside as well as the factory green firewall - go figure.   Whatever the paint material was (primar or paint), the underside was clearly black throughout with significant body color overspray.  The car is an original SoCal car - never spending anytime outside of the area.  I found no signs of non-factory undercoating anywhere.  

Regarding the green firewall - my only guess is they ran out of black paint that day and dark green was the closest alternative.  
If your car is dark green then the firewall just got sprayed with body color... there was an original 68 Sequoia green car with complete Sequoia green firewall.

[Hans L]

Regarding the green firewall - my only guess is they ran out of black paint that day and dark green was the closest alternative. 
If your car is dark green then the firewall just got sprayed with body color... there was an original 68 Sequoia green car with complete Sequoia green firewall.

69 69 Cortez Silver Car.   I've seen a few others LA Cars, same build week (Daytona Yellow & another silver LA car) that also had the green fire wall.  It's metallic as well!

Hans

[firstgenaddict]

That would be great to see the judges looking at an unrestored Daytona Yellow car with a Green firewall...

Ford during the 30's-40's used left overs of paint, mixed it all together and used it to dip parts for shipment to dealers etc, most of the time it was black or dark brown, I am sure there were short instances of some off colors.

[janobyte]

I'll post some pics of mine before it gets covered up . Red Oxide final before bare metal--liberal from mid car back/frame rails.traces of gray was in the tunnel/front.Black--body color overspray/liberal---undercoat. Took it down with water based stripper, which pretty much allowed 1 layer at a time to come off. The Ash Gold weeped . Almost half the underbody had body color overspray on the driver's side,very little on the pass. My bodyman went with another supplier for the GM blackout, suppose to be higher quality---very happy with the shade. Guy doing my car wanted to replicate the overspray underneath ,I'm out on that.

[NoYenko]

Since this thread was brought up again I thought I would post some pictures of my floor after painting. I had found black on the bottom with grey primer overspray on the front 20". The slightly duller firewall blackout paint sprayed over the grey primer on the firewall vertical surface. The sides of the floor and rear frame rails received body color overspray. I could not figure out how to accurately reproduce the grey paint runs found at the firewall to floor seam so I didn't do that. George