Permatex Cure Time

sandlapper

Veteran Member
Oct 9, 2020
1,185
SE CSA
dunno which "black" but new GM sbc crates come with black silicone on china walls. I wouldn't sweat the color or temp so much. Although; Might behoove ya to look up & read product info specs on manufacturer's site. RTFM.
 

Elliott Taylor

Veteran Member
Nov 24, 2020
156
Thanks for the advice! I'm going to go ahead and install the manifold tomorrow with the Right Stuff Grey. It is going to be 52 degrees here tomorrow, and this Permatex has a 90 minute cure time. It also has a 5 minute work time, so I should be okay.
 

Elliott Taylor

Veteran Member
Nov 24, 2020
156
Just thought I'd give you guys an update. Last night I did a test by trying to bond 2 aluminum cans with The Right Stuff. I left it outside in freezing temperatures, and the sealant didn't cure..It was still wet this morning after about 12 hrs.
 

badazz81z28

Veteran Member
May 4, 2001
21,796
Alabama
Just thought I'd give you guys an update. Last night I did a test by trying to bond 2 aluminum cans with The Right Stuff. I left it outside in freezing temperatures, and the sealant didn't cure..It was still wet this morning after about 12 hrs.

Unless the material cures by chemical reaction (2 part mix), it won't cure outside temp parameters. Permatex RTV cures by "room temperature" vulcanizing. Of course meaning, it needs temps about 60+ to cure. It will cure at lower temps, but will take longer.
 

COPO

Veteran Member
Lifetime Gold Member
Sep 15, 1999
21,608
Ontario, Canada
Permatex ultra grey is what you should be using on the intake china walls.
https://permatex.com/products/gaske...ex-ultra-grey-rtv-silicone-gasket-maker-5-oz/

Valve covers, water pump, intake manifold end seals, thermostat housings
DD2E4FCF-3089-4ACB-BECF-1CC8AE901A4D.jpeg


DIRECTIONS:
1. For best results, clean and dry all surfaces with a residue-free solvent, such as Permatex® Brake & Parts Cleaner.
2. Gaskets are best formed using a 1/16″ to 1/4″ (2 to 6 mm) bead.
3. Apply a continuous and even bead of silicone to one surface; surround all bolt holes. Assemble parts immediately. Finger tighten bolts until material begins to squeeze out around flange. Allow to dry for one hour then retighten 1/4 to 1/2 turn.
4. Silicone dries in 1 hour, and fully cures in 24 hours. Allow more time in cold or very dry conditions.
5. Replace cap after use. Clean hands with dry cloth or Permatex® Fast Orange®Hand Cleaner. Clean tools with non-flammable cleaning fluid. NOTE: Not recommended for use on head gaskets or parts in contact with gasoline.

Chart https://www.permatex.com/gasket-maker-comparsion-chart/?locale=en_us
 
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Elliott Taylor

Veteran Member
Nov 24, 2020
156
I ended up installing the intake tonight with The Right Stuff Grey, taking into consideration its quicker cure time and the colder temperatures here. It seemed to be hardening up well when i checked it about an hour ago, and the next two days are nice here.
 

Twisted_Metal

Administrator
Staff member
Lifetime Gold Member
Feb 26, 2004
30,830
Bloomington, MN
I used The Right Stuff (black) on my intake many years ago.

Great product!

It hasn’t leaked any coolant or oil in over a decade.

I did have to reseal a couple of the center bolts due to oil wicking up the threads.
(I hadn’t put anything on them when I installed the intake. :screwup: )
 




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