What's The Black Stuff, Undercoating Or Grease?

[Patrick T.]

I've ordered the field judgeing guide, but still haven't got it yet, its "In the mail". I have my '67 tire carrier out, cleaning it up after 32 years. The vertical portion, which is perpendicular to the road, is either sprayed with undercoating or is just old road grease, can't seem to tell which. It looks like everything else that was under the car, just rock hard grease. The bottom horizontal portion which is parallel to the road is clean, black fiberglass.

This probably is a no-brainer, but I've looked thru Noland Adams guide and every Corvette book I have and can't find a photo which gives a clear shot of the vertical side. I'd like to do it right the first time. Can anyone set me straight? Got my first Corvette show (with this car) in 2 weeks. Thanks Patrick

[Terry M.]

Re: What's The Black Stuff, Undercoating Or Grease *TL*

Patrick,

This is one of those that are hard to nail down without seeing it, but it might be overspray from the blackout operation on the mufflers. Of course if you have side pipes that rules this idea out. If you are not sure leave it alone and the judges will tell you, or they will be a puzzled as you are.

Terry

[Patrick T.]

Terry, I Do Have Sidepipes......ntx

[Terry M.]

Re: Then I give up...ntx *TL*

[Chuck S.]

Re: Then I give up...ntx

Terry,

On my own car, a '70 coupe, I seem to remember that an undercoating-like material was apparently sprayed on the fiberglass underbody directly over the differential and on the vertical surfaces of the storage compartments. My theory is that it was applied to reduce road and gear noise in the passenger compartment. Have you also observed this, and if so, could overspray from this process be the stuff Patrick is observing on his mid-year?

After I read the posts, I checked my AIM, but it shows "deadening material" being applied only to the rear of the front and rear wheel wells. No mention of any application to the underbody. I know it was done differently on the wheel wells; the rears had undercoating applied further forward than indicated by the AIM.

Chuck Sangerhausen

[Duke W.]

How about this theory

The undercoating evident on the spare tire carrier is merely overspray or an "error" (accidently hit the trigger while swinging the gun up, hit a trigger a second early, etc.) from the wheel well undercoating operation. Maybe it was built on a Monday and the operator had a tough weekend!

Duke

[Patrick H.]

Similar find

Hi,

My 71 has similar material on the tire carrier sides, as does Dad's 72. I agree that it looks like overshoot from the wheel well operation. The 72 also has it on the sides of the rear compartment boxes.

Hope this helps.

Patrick Hulst

[Terry M.]

Re: Then I give up...ntx *TL*

Chuck,

My '70 has it only in the wheel wells and most/all 1970-1972 have "sound deadening" as called out in the AIM, however this was a human operation. Those guys could have been having a "sound deadening gun fight" under there from time to time.

However best bet is for Patrick T. to get second and third opinion from people who can see what he is talking about and have seen a lot of this vintage Corvette. Words (regardless how many) sometimes fall short. Good quality photos might be another answer.

Terry

[Chuck S.]

Re: Then I give up...ntx

Terry,

Yeah, you are right. I thought it might be a plausible explanation for undercoating in that area. Expertise in a given year class is always better.

Regretably, I have no pictures of the underbody before it was cleaned; I just remember cleaning off undercoating-like material. Sounds like others have made similar observation in '70-'72 cars. Probably operator technique,or as Duke said, "hangover".

Chuck Sangerhausen