Firewall Sealer - 1966 Corvette

[Dane H.]

I am finishing the restoration on my 1966 Corvette and need to apply sealer around the outer heater box cover and other firewall locations as applied at the factory. Can anyone share recommended products and methods to achieve the factory look and finish?

[William F.]

Re: Firewall Sealer - 1966 Corvette

3M makes the black pliable rods that can be formed into place. Paragon and I think Corvette Centrals this product.

[Michael M.]

Re: Firewall Sealer - 1966 Corvette

I always thought that this material was sprayed on. I have had great success with a product called Submarine Sealer Cooler Coating. It has refined asphalt and waterproofing oils in it to give a rubberized result. It is also the correct black color.

[William F.]

Re: Firewall Sealer - 1966 Corvette

If you're talking about sealer around the wiring harness plugs and similar locations, it's not sprayed on, it's the 3M stuff I mentioned.

[John H.]

Re: Firewall Sealer - 1966 Corvette

If you're talking about sealer around the wiring harness plugs and similar locations, it's not sprayed on, it's the 3M stuff I mentioned.

Actually, in production, those firewall grommet/penetration applications used a liquid reclaimed rubber sealant applied from a flow gun.

[William F.]

Re: Firewall Sealer - 1966 Corvette

John,
Thanks for the straight skinny on how it was done at the factory,but isn't the 3M "dum dum" I mentioned the most accurate way of reproducing these seals, when restoring?Please correct if I'm wrong; I'm a firm believer that those posting,myself included, should do their best to give accurate information, not just "Don't know, but I think---

[John H.]

Re: Firewall Sealer - 1966 Corvette

John,
Thanks for the straight skinny on how it was done at the factory,but isn't the 3M "dum dum" I mentioned the most accurate way of reproducing these seals, when restoring?Please correct if I'm wrong; I'm a firm believer that those posting,myself included, should do their best to give accurate information, not just "Don't know, but I think---

William -

The 3M "Strip-Calk" is used today for many sealing applications where a similar string sealer was used back in the day, but I don't recall the name offhand of the current 3M liquid sealer product that's similar to the 60's black sealant that was used on the firewall grommets. Wayne Womble probably has the name of the current 3M product.

[Michael G.]

Re: Firewall Sealer - 1966 Corvette

John,
Thanks for the straight skinny on how it was done at the factory,but isn't the 3M "dum dum" I mentioned the most accurate way of reproducing these seals, when restoring?Please correct if I'm wrong; I'm a firm believer that those posting,myself included, should do their best to give accurate information, not just "Don't know, but I think---

Somtimes Bill thats all we got brother......best guess, ya know.

[Barry H.]

Re: Firewall Sealer - 1966 Corvette

Dane, To duplicate the look of the black rubber/asphalt sealer I use an inexpensive black asphalt roof sealer caulking in a tube.
It is easy to use with a caulking gun, & can be wiped with kerosene, plus easy cleanup with same. In over 30 years & many Top Flights & a Duntov, I have never received a deduction for this compound. There are many places where Strip Caulk was used, but for most wiring grommets & heater box apps the asphalt type caulking was prevalent.
Barry Holmes

[Tom R.]

Re: Firewall Sealer - 1966 Corvette

Kind of relevant I hope. I've used the 3M strip caulk to seal the inner door moisture barriers to the inner door panels. I believe the factory used something similar.