Just found out (the hard way) that this stuff goes bad after a few years. I used some on my intake and noticed it was still "gooey" after almost 20 hours.
The tubes do not have an expirey date but trust me they DO expire.

To verify this and that it wasnt something else like it just being cold outside... I tested a brand new tube of the exact same stuff (permatex ultra copper High Temp RTV gasket maker) and the old tube. After less than an hour the new stuff skinned over wherease the old tube was as gooey as when i first squeezed it out.

This might also be why some people have trouble with leaky intakes.... even after waiting 24 hours for it to "cure". An old tube of that stuff won't be curing any time soon.... and would fail rather quickly. Toss out your OLD tubes of this stuff people to save yourself from doing this job twice!

I'll post a followup on how my "test" works out after a day or 2. Its not looking good so far

BTW old tube was around 4 years + old.

 

Temperature has nothing to do with curing RTV. RTV "cures" from exposure to the moisture (humidity) in the air. Its possible for thick layers of RTV to cure outside, and never really set up at a depth of 1/8" or so, because the cured "skin" cuts off the supply of moisture from the air.

 

If you want to eliminate intake leaks use "The Right Stuff" gasket maker. Its well worth the extra $

 

Humidity: 94% (vancouver weather )

The old tube sample does not solidify at all or skin or anything. (4 hours later).
New tube sample is like rubber now.

I'll verify this tomorrow at work, but i'm quite sure temperature does matter as does humidity (moisture) for silicone type sealants. Putting my test in the oven at around 100°C did speed up drying considerably for my test...

 

Where do you get this stuff?

 

I buy a new tube pretty much everytime I do one... I keep my old ones around for minor stuff, but the intake seal is just too important to skimp $7 on.

 

Most part stores carry it.....

Cheeze quiz can part # 25223 cost around $18.00.....
Grease tube type kit part # 99070 cost around $30.00 .....

 

Well the worst part was that I did buy a brand new tube (hence how I was able to test them both side by side) but my buddy had an old tube in his toolbox so we just thought we'd use that first... without thinking that this stuff goes bad. Mind you we did look for an expiry date before we did this so we "thought" it would be fine... I guess we thought wrong

As for the product itself, the dried new tube stuff looks great, its very solid and began to skin over quickly too. I won't have any problems using this stuff again so long as its a fresh tube

 

I talked with permatex directly yesterday and they said the stuff has a 2 year shelf life and if its older then that it will never properly cure. They apologized for not having an expirey date on it but didnt really commit to anything. Going to redo the gasket today.