Hi Guys,I started my restoration about 4 weeks ago & am moving along...Tonight after work I drilled all the spot welds out & removed the top dash panel that was rusted out on each end from the windshield leaking.I have questions about the sealers that were under the old dash panel, there was some kind of foam sealer that was above the spot welds between the cowl and the dash panel, not like seam sealer.. more like low density foam. The other sealer in question is on each end of the dash panel where it meets the cowl (out side of the windshield) looks like seam sealer, this was between the lower (front edge)of panel & the cowl. Looks like the factory put it on pretty thick in that area to cover the transition of the two panels.What are the best type of sealers to use when I install the new dash panel?68birdThanks
Restoring 68 Bird (coupe)
I have never installed the part you are working on but think I can suggest products to fill your needs.Does the foam stuff look like it was in the seam when welded? Theres no aftermarket weld-thru sealer I know of, but something of that nature may have been used originally. Your new seam should be sealed normally, even if thats the case. With regular seam sealers (see below).There IS a product called pillar foam, a 2-component fast curing expanding foam that is used to seal around air baffles and fill hinge posts in newer vehicles. It is not intended to be exposed to weather or to be painted. Takes a special applicator gun and disposable mixing nozzles. On the cheap, you can get this "spray foam" at home improvement stores but being a single component product, it it not as durable. I really don't recommend any foam at all though, because it traps moisture if exposed to it. Even just condensation. Don't use foam where rain or wash water can potentially reach it. Seam sealer is what I would use unless a foam is required on the area in question. No foam or sealer should cover bare steel in any case, at least primer is needed for proper adhesion and metal protection.Sometimes the situation calls for a runny sealer that flows into place. In those instances, again theres a two-component paintable "self-leveling" seam sealer available. It flows easy and dries fast. Stays flexible. You will normally want to mask off where the excess is gonna run out of the seam. Its good for drip rails and some cowl seams. Again with the applicator gun and mix nozzles, but also maximum durability. Apply after all sanding and don't touch it just paint it, or apply before final primer if a mess is anticipated.Preferred seam sealers- well, outside (anything out past the door and glass seals) the ultimate is a two-component product again, in an Automix cartridge. You can actually sand this stuff, it dries shiny and fast and paint sticks best if its dried and scuffed. I prefer to apply it smooth with a bondo spreader. It can also be smoothed with a brush wetted with wax and grease remover while wet. They call it heavy bodied but I think medium is more like it. Feels like vinyl when dry. Its not runny but its kinda tough to make a thick coat with it. I prefer to apply this before final priming for best appearance. It sands easily but doesn't really featheredge. Inside (anything inboard of the door and glass seals), I like this single component urethane. It needs plenty of dry time but stays flexible forever. Best to apply it after all the sanding is done:The gobs of sealer smushed into the corners of the dash to windshield post seam, I think I know what you're talking about and thats a good spot for that heavy bodied two component stuff. Especially if it bakes in the sun and gets painted and shows a little. But I believe the factory used a non-hardening butyl rubber there, not exactly like but not too different from ribbon sealer used for OE-type glass bedding. Another alternative there might be strip caulk which is soft gummy butyl that takes decades to harden but can swell and migrate when really hot. Yet another alternative would be urethane windshield adhesive on that spot since you or your glass man will probably use some nearby anyway. No, I'm not a 3M salesman and yes similar products may be available in other product lines but these are what I want when sealer time comes. Theres bound to be something useful among the products suggested, I hope this helps shed some light!
idrivejunkThanks so much for all the great info!
Restoring 68 Bird (coupe)
You're welcome. Enjoy your project!