Ever had proseal not cure?

I sealed the pvc ribs in my -10 elevator and trim tabs 17 days ago. I mixed up a batch for the elevators and mixed up a separate batch for the trim tabs. The elevators cured fine, but after a week of the tabs not curing at room temperature, I became worried. They have been sitting in front of a space heater that is keeping them at a constant 100 degrees for four days now and they are the little bit of sealant that I can poke with a little screw is still as gooey as it was the day I installed the ribs.

I'm thinking that the digital scale I used gave me a false reading. The color of the sealant is also lighter than what I feel a properly mixed ratio would provide.

Is there any remedy that I can do before I open these tabs back up and attempt to clean all the old sealant out?

clutch22 said:

Is there any remedy that I can do before I open these tabs back up and attempt to clean all the old sealant out?

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Sorry but you may as well start cleaning

Don't forget to stir the hardener, if you got some off the top without mixing first this could be your problem.

Proseal

When I was sealing my tanks my last batch was not curing. I mixed it just like all the previous batches. I took the tanks home and I had to let them sit for all most four weeks before they cured. They finally cured and I've never had a problem with them. I'd take the heat off of it and let it cure at room temp. 70-80 should be fine.

I now work on military helicopters and use proseal all the time. We never measure. We get a blob of white and add the black until we have nice slightly dark shade of gray. We alway mix it by the shade of gray. I repaired a fellow RV's tank and I used this same method of mixing and it turned out great. If you have never mixed it I guess you should do a few batches by weighting it, mix it then add just a little more black. That should get you use to the correct color. Then mix the future batches by color. If it looks a little too light add a bit more black. All it will do is cure faster.

Proseal is activated by the catalyst, which is the black stuff. If you get the ratios wrong, it'll cure faster or slower, but will eventually cure. It is not like epoxy, where the mix ratio is critical to both curing and to the final strength.

If I was you, I'd let the parts sit for a while - a month or more if necessary. Unless you need to fly them soon, there is no rush, so why not wait and let the chemistry do its thing, albeit slowly?

Well I guess I'll let it sit for a while and see. I have used industrial epoxies a lot and know how accurate the mix ratio needs to be for proper cross-linking. I just assumed Proseal behaved in the same way...

bhester said:

When I was sealing my tanks my last batch was not curing. I mixed it just like all the previous batches. I took the tanks home and I had to let them sit for all most four weeks before they cured. They finally cured and I've never had a problem with them. I'd take the heat off of it and let it cure at room temp. 70-80 should be fine.

I now work on military helicopters and use proseal all the time. We never measure. We get a blob of white and add the black until we have nice slightly dark shade of gray. We alway mix it by the shade of gray. I repaired a fellow RV's tank and I used this same method of mixing and it turned out great. If you have never mixed it I guess you should do a few batches by weighting it, mix it then add just a little more black. That should get you use to the correct color. Then mix the future batches by color. If it looks a little too light add a bit more black. All it will do is cure faster.

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I love this!
Years ago, the pro seal came with instructions to mix by weight or volume. IIRC it was 7 to 1 by volume. I have always just eyeballed it that way. Probably always aired on the blacker side but did mix it lighter one time and it eventually cured.

I have used the stuff that is out of date by 12 years and it takes a long time to cure but it does cure. If the mixture is not right it will also cure. Give it time it may be a couple of months but it always seems to cure, and shows no difference after it sets.

Last month I used 1 ½ year old pro seal that had been setting the 100 + degree Texas heat last summer and used to glue my vents on. The white part was starting to harden (I was breaking sticks) up but, I mixed it anyway. It took a full month to setup but, it did. I think you would shear the AL sheet before those vents come off!

Thanks guys!

Very glad to read this thread. I mixed up my first batch of Proseal about 3-1/2 weeks ago. I was a little concerned that it was curing very slowly. I worked with the batch that night, and the next afternoon what was left over was still almost exactly the consistency it had been the night before (so I used that to finish up some stuff). Several days later it was still a little gooey. In fact, it's STILL tacky and soft, but it curing -- slooooowly. To be fair, it does live in a garage that's been around 40-45 degrees unless I'm out there with the heaters going, so maybe 6-8 hours a week it gets into the mid 50s.

I was expecting this stuff to be like epoxy; if that doesn't set up within a reasonable amount of time, you're screwed. But, I check the parts every few days and they do seem to be gradually getting closer to being cured. Also interesting to read the mixing feedback. I was very careful to use my digital postal scale to weight the parts, but I knew there could be some variation since I only mixed up 1.1 oz to do get my feet wet (or would it be "get my feet sticky"?) with some small jobs.

Proseal Cure time

I had exactly the same question about a year ago.

http://www.vansairforce.com/community/showthread.php?t=83664

At the time the temps were a bit chilly and it took a good 3-4 weeks to get good and hard, but it got there and is perfectly fine today. As the temps got warmer through the Spring and Summer and my work continued on my tanks the cure time got down to about 2 days. As others have said, you're probably just fine.