Technical Permatex oddity...

Finishing up 327 Chevy for my 32 roadster, installing the oil pan.
Very clean gasket mating surface on the block, brand new Dorman oil pan (which are actually very nice for 65 bucks). I got one of those permit tax one piece gaskets. I'm anal when it comes to leaks and a guy at work just had the exact same gasket leak and had to remove the pan with the car in the engine. As such, I put ultra black permatex on both sides of the gasket.
That's what I realized I had the wrong oil pan gasket - the Dorman replacement oil pan actually uses a thick front seal - so I proceeded to take all the bolts out and remove the pan. much to my disbelief, the pan popped right off when I loosened up all the bolts - NO permit tax ultra black stuck to the bottom surface of the oil pan or to the block. The permatex ultra black was however essentially at 1 with the blue velpro one piece oil pan gasket and completely dry After having it installed for 15-20 minutes!
???
I've never had permatex not stick to the engine block or the oil pan - I'm usually scraping that stuff off with a razor blade. I thought there may be something wrong with the tube of permatex, so I tried to stick together two pieces of clean steel I had in the garage - they stuck together like mad, what I'm typically used to seeing.
Felpro tells you not to put any permatex on that gasket, permatex recommends using their non-hardening rubber gasket sealant in the corners. I think I may do that this time around, worst case scenario the pan has to come off again and If that stuff doesn't get hard, I can clean and reuse the $40 gasket.
I really just want to understand what mechanically happened to the permatex that caused it not to stick to the pan or block... And what made it fully cure in 15-20 minutes

 

I don't know, but perhaps it's more a question for a chemist than a mechanic.
I'm interested!

 

Did you use wax & grease remover before putting the goop on? That stuff leaves the surface surgically clean, and the gasket goop should stick like shit to a blanket.

 

Pre 1975 sbc oil pans use the thin front gasket , post 1975 SBC oil pans use the thick front gasket . The difference is in the pan . As to your adhesion problems ,both surfaces were ( obviously) contaminated , most likely the cleaner you used left a a residual compound / coating on the surface .

 

I think the acetone and lacquer thinner did leave some sort of residue... That made the permatex not stick and dry fast. I cleaned it with brake cleaner for the second go around and it seems to be much better

 

This is the response that I got from permatex... I still liked in mechanically know what happened (The response doesn't explain anything - just the standard "You're not using it for it's intended purpose")...

Ultra Black normally does not take 15-20 minutes to dry. It will take approx. an 45 minutes to an hour to skin over, and achieve a full compete cure in 24 hours. Now Permatex The Right Stuff will completely skin over in 10 minutes and operation is immediately after assembly.



Now when using gasket makers such as the Ultra Black, Grey, and Reds, and it is also true for The Right Stuff Gasket Makers, is that traditional cut gaskets are not used. So these gasket makers take the place of the oil pan or any assembly gasket. We recommend either using the Ultra Black gasket Maker by itself without a gasket, or just use the felpro gasket without a gasket maker or sealant.