[6d7gto]

Did every seam on the car get sealer from the factory? In other words, wherever panels come together? Car (1967 GTO hardtop) has been blasted and painted in epoxy so there is no seam sealer anywhere now. If every panel gets seam sealer, what kind should I use? Want it to look like the factory did it. Thanks.

[ZeGermanHam]

The short answer is no, not everything was seam sealed at the factory even though there are some places where they should have used seam sealer but didn't. For example, none of the floor pan braces were seam sealed, which seems like an odd place to skimp. And sometimes it depends on which factory your body was assembled at. My Pontiac, MI built '66 did not have any factory seam sealer along the top edge of the front body mount boxes, but '66s built at other plants did get seam sealer in that location.

So it's not always straightforward if you're trying to recreate the way it was before you had the body blasted without any reference photos. If you have questions about specific areas, we can probably track down that info for you fairly easily though.

[dhutton]

Just don’t get too carried away and apply sealer that prevents moisture from draining at low points etc.

Don

[dataway]

It always appeared to me that they didn't seam seal all metal to metal seams, but they did seam seal all metal to metal seams where one side was exposed to the outside and the other exposed to the interior of the car, including trunk area.

For instance floor braces were a metal to metal seam, but completely on the exterior of the car.

[6d7gto]

So the sealer was just for moisture, not to keep panels from squeaking?

This car will never see a day of weather or moisture. For one thing, we don't have any weather/moisture here in Southern California! Plus it will be a concours show car. To give a real life example: The car and I both came from Maryland where we'd leave potato chips out for a party and by the end of the party they'd be soggy. Where I am now, you can literally leave chips out for a week and they'd be just as crispy as the day they were bought!

Anyway, I just want it to look like a factory original, but would a concours judge even deduct points for a lack of seam sealer?

If that is the case, I might just do the obvious panels like the cowl and trunk and take my chances with the judge if it won't rattle or squeak without being sealed.

[Formulabruce]

Seamsealer as listed for warranty work at my dealership has/ had primary function to seal the "Cab".
So floors to rockers (inside) Inner wheel houses to interior. Firewall to toe pan, and air horn areas. Roof was exempted and only used caulk on gutter trim.
To help seal the " cabin" the rear trunk drop offs to tail and body were sealed for exhaust related concerns getting in the trunk, which is vented to the main cabin through the " B" pillar vents.

[ZeGermanHam]

Originally Posted by 6d7gto

would a concours judge even deduct points for a lack of seam sealer?

Yes, they will deduct points if they are good.

And seam sealer is not used to prevent squeaks - it's for keeping moisture out. And as Formula mentioned above, probably exhaust fumes, too. Also keep in mind that even though you may not think you need seam sealer due to how you plan to use the car and where you live, please keep in mind that someone else will own your car after you're gone. Build it right, and build it to last! In other words, don't forego the use of seam sealer.

[MUSLCAH]

If there is a seam….seal it. Like noted above….don’t seal up the drain holes. If your building a points car…i have no clue about the width and thickness is allowed for seam sealer…..lol..But I do know a guy that lost points for the incorrect valve stem caps….so make sure you have the correct caps ….or you’ll be looking up at First Place.

[6d7gto]

Thanks guys! Guess I will use the stuff wherever moisture could be a problem. Going with a 3M brand called 'Ultrapro sealant' 08300. It is very messy and dries very quickly but I will use mineral spirits on a stiff brush and tape around the edges to keep it where I want it to go before using the brush to give a factory look.

Thanks again for all your great advise!

[nbn]

3m 08656 brushable seam sealer is what I typically use on restorations.
Self leveling will only run on you and create a mess. Remember also, your car was built on an assembly line by someone whose job was to slap on seam sealer as it was moving down the line. As much as some people would want to, precision and uniformity was not practiced on the line. Proper seams will have brush strokes in the sealer.

[6d7gto]

Originally Posted by nbn

3m 08656 brushable seam sealer is what I typically use on restorations.
Self leveling will only run on you and create a mess. Remember also, your car was built on an assembly line by someone whose job was to slap on seam sealer as it was moving down the line. As much as some people would want to, precision and uniformity was not practiced on the line. Proper seams will have brush strokes in the sealer.

The 3M product (08300) I just now tried to apply made a big mess. Terrible product for this job. When trying to brush it, it beaded up in tiny balls and globs went everywhere (but not where I wanted it)! Had to completely remove it with lacquer thinner. Will try your sealer of choice next. Thank you for responding.

[ZeGermanHam]

When I did the seam sealing on my car, I used SEM brand with a caulk gun in most areas and it was fantastic. Very easy to work with, manageable set time, and I didn't make a mess. I also used some Dominion Sure Seal brushable seam sealer. It was also pretty nice and easy to work with, but I preferred the SEM product over the Dominion.

[Hammertime Mike]

I've had good luck with Dominion brand seam sealer. My experience with seam sealer is that it skins pretty quickly . So you pretty much need to lay it down to your satisfaction the first time.

[MUSLCAH]

That brushable 3m seam sealer stinks …big time….make sure the exhaust fan is on….or wear a respirator if your head is stuck up under a wheel well….

[6d7gto]

I ordered several brands that folks suggested and will test them all...then report back with my results. Had to go through the internet because California stores no longer carry the good stuff due to VOC restrictions.

[nbn]

Originally Posted by 6d7gto

I ordered several brands that folks suggested and will test them all...then report back with my results. Had to go through the internet because California stores no longer carry the good stuff due to VOC restrictions.

Any luck?

[6d7gto]

Originally Posted by nbn

Any luck?

Yes. Tested the 3M brand under the rear inner to outer fender wheel seams. Goes on smooth and gives time to spread out but still sets up too fast in my opinion (or I'm just too slow)!

Tried Transtar in the trunk inner wheel house to trunk mid section. Transtar set up even quicker (slightly) but also went on smooth. Both about the texture of peanut butter.

Have one more brand to test and will get back to give more results. Those guys on the line that originally did this for a living must have been extremely fast and much more skilled than myself.

[nbn]

A little trick I failed to mention when running sealer.....if you are wanting to smooth things out more than the factory did it, keep a little thinner of to the side,if the sealer starts to set up, dab your finger in the thinner and lay it out across the sealer. It'll smooth things down for you.

[Hammertime Mike]

Originally Posted by nbn

A little trick I failed to mention when running sealer.....if you are wanting to smooth things out more than the factory did it, keep a little thinner of to the side,if the sealer starts to set up, dab your finger in the thinner and lay it out across the sealer. It'll smooth things down for you.

X2 on thinner

[6d7gto]

I tried the Dominion brand and it is the easiest to use, lays down smooth and stays pliable longer than the other brands...plus it leaves brush marks duplicating original look. Best out of the three I tried. Just one man's opinion..