PRO-Seal expiration date

mkrieg · #1 11-07-2005, 01:26 PM

Back at the beginning of May I bought a can of PRO-Seal from Aircraft Spruce. The hot summer kept me out of the garage and away from the wings; but, now I'm ready to seal the tanks. I noticed that the PRO-Seal has an expiration date of 09/2005. The question is - how much shelf life is there, really? The containers have never been opened, although I did store them in the garage -- sometimes as high as 110'.

Mike Krieg, RV-8 484MD
82271 -- Wing Kit

Davepar · #2 11-07-2005, 03:18 PM

Bummer. Keeping them in the fridge would have extended the life somewhat, especially compared to 110F.

The worst case scenario is so horrible, that I personally wouldn't risk using it. If the Proseal doesn't set up enough to hold out leaks, your only reasonable option will be to order all new tank parts.

painless · #3 11-07-2005, 03:43 PM

Since you will be using the proseal for tank construction, I would not take a chance on it.

I would keep it, however, to use in other areas where proseal can come in handy. I suspect that your current batch will still set, just that it may take longer.

I have found that the base component of older proseal will tend to get real stiff and be more difficult to mix and to apply where you want it.

Regards,

Captain_John · #4 11-07-2005, 05:08 PM

Personally, I would mix up a batch and see how it sets up.

If is performs satisfactorily, you may want to use it.

You will need a standard to compare it to. The problem is, if you have no experience with the stuff, you will need to buy another can for a perfomance baseline in order to conduct an accurate comparison.

But I suppose that with the second can purchased, you may as well use the new one for the tank ribs and the old one for other tasks!

CJ

Captain_John · #5 11-07-2005, 05:13 PM

BTW, the fridge thing is TREMENDOUS!!!

When I do 2 ribs at a time, I mix up 80 grams of product at a time. After buttering up the first rib, I flash freeze the remaining goo. When I am close to finishing that rib, I slide the remaining product into the fridge. A few minutes before I need it, I pull the stuff outta the fridge and put it to use. It really destresses the process by lengthening the pot life to a leisurely pace.

I find that it takes about an hour and a half per rib for me.

Here is my first tank:

CJ

mkrieg · #6 11-07-2005, 05:41 PM

Yep, I get it.

And the neat thing is you guys aren't the least bit vague in your answers.

OK, buy fresh product, refrigerate until (and during use), and keep the old stuff for non-critical sealing tasks.

Thanks for the help!

Mike Krieg, RV-8 484MD
82271, Wing Kit

Stephen Lindberg · #7 11-07-2005, 09:51 PM

I have some tank sealant that is two years out of date. It is thicker than when it was fresh, but it sets up fine. I'm still using it for odds and ends. My understanding is that the white goo reacts with oxygen in the air and thickens up slowly with time. The black goo is a rich source of oxygen atoms and speeds up the process manyfold. So, the problem with old tank sealant is not that it won't set up, but rather, it gets too thick to use easily. Steve

RV7ator · #8 11-07-2005, 10:46 PM

...so it oughta work for tank sealant.

If anyone has trouble sleeping at night, read MIL-S-8802, and it's straight to la-la land. This is the controlling spec for tank sealant. Flamemaster manufactured the goo I got from Van's, the thinly disguised part number reflects the 8802 pedigree. I downloaded the doc from somewhere years ago. Try Goggleing for it to back up your documentation file when you qualify your MIL spec RV.

Generally, store any kind of reactive compound in the freezer to extend useful life: CA adhesives, tank sealant, epoxy primers, etc. Make sure to label it properly so your wife doesn't put it in the spaghetti sauce.

John Siebold

Captain_John · #9 11-08-2005, 05:07 AM

...in case you haven't seen Paul Trotter's whitepaper on proseal, CLICK HERE!

Paul has done a GREAT job on compiling data and making it simple to understand!

Nice job, Paul!!! It helped me ALOT!

CJ

ptrotter · #10 11-08-2005, 10:18 AM

CJ,

I think the shelf life is conservative so if the consistancy of the parts seems normal, it will probably mix up and cure fine. I had some tubes go bad that were within their expiration limits, that were stored too warm. They got too think to mix right. I used them for so non-aircraft use and they still cured ok.

The best thing to do is store sealant in a cool temperature, both unmixed and mixed.

On the other hand, tanks are too critical to take any chances and the stuff is not all that expensive.