[macrafic]

How much time do I have, once I open a tube/jar of proseal, to use it?

I understand its usable life can be extended by putting it in the refrigerator. How long does this extend its life?

 

[Frank]

The two part tank sealants (ProSeal, Flamemaster, Chem-seal CS-3204, etc) all have recommended shelf lives. The stated shelf life is a commercial/legal/liability, etc shelf life and required by mil-spec standards. The container or spec sheet will tell you what it is. The practical shelf life (un-mixed) is as long as it is still mixable and usually lasts until the container is close to empty. It is not unusual to pass cans around for a couple of years.

As an aside, an acquaintance of mine who worked as a sealants manager for Boeing built a wooden and fabric SE-5 about 30 years ago using nothing but expired glues and sealants after Boeing discarded them. No part of the plane has failed due to building materials.

 

[mlwynn]

Just to Verify....

I have several tubes of proseal--the cartridge you mix with its internal stirrer and then pop into a caulking gun. They expired last October. I have kept them in a cold refridgerator and need to use one to seal the firewall/front skin joints. This is not a fuel tank, so I don't suppose that failure would be a major disaster. Do I understand that these should really be just fine?

Thanks,

Michael Wynn
RV 8 FWF
San Ramon, CA

 

[WilburD2]

Proseal timing

Having worked a while with proseal in the commercial world, I always could tell when the stuff was useless because the mixture would never set up. So, I'd end up having to scrape the old stuff out, clean it all up with MEK or toulene and start all over again.

So when you mix a new batch for use, leave a little blob set aside that you can check to see if the stuff skins over at the end of the working time and to check for full cure time without having to touch the parts you sealed.

If the parts you sealed are dry and cannot make a fingerprint in the sealant, press on!

 

[macrafic]

Once you mix the proseal, such as what happens when you use the tubes, how long is the proseal good for? Can it be preserved for a longer period of time, say be refrigerating it?

 

[WilburD2]

Yes to the fridge!

Rick, yes sticking the sealant in the fridge will prolong its shelf life. I've heard of cases (on here as well as at work) where people would stick the mixed tubes in the freezer to prolong its working life. Then again I've seen stuff that supposedly had a 15 minute working life set up in less than 5.

Now how long it will actually last once mixed.. Depends on how its mixed. Plus the stuff is temperature dependent. The warmer it gets the faster it'll set. Thats the problem with the pre-mixed stuff, once its frozen bringing it back to a working temp could accelerate how fast it becomes useless.

Best bet is to go with the cans so you can control just how much you actually use without having to throw away expensive leftovers.

Hope this helps

 

[MNAv8or]

I use the cans and mix as needed. The only time I use tubes is if I have a job big enough to where I know I will use the whole tube. They do make proseal in 2.5 oz and 6 oz tubes so you do have somewhat of a selection to choose from.

I have put mixed sealant in the freezer, pulled it out six months later and it worked just fine. The best way to see if the stuff is still good is to do what WilburD2 says put a little blob aside to see if it sets up.

WilburD2 -- I feel your pain! I put a windshield in a Cessna 340A and the sealant we got right from the manufacturer was mixed wrong at the plant so it wouldn't set up even after 3 days under heat lamps to try to get it to kick off. Try pulling out 10,000 dollar windshields and trying to clean them up without using chemicals.