Just FYI

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elody21

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Before you throw out old PR thinking it is too old to work, give it a try. I had 2 cans of PR one, 3/4 gone and one without the seal broken. Both cans were 2 years old. The open one was no good but the one with the seal unbroken,the full can, works just fine. I guess one would deduct that maybe the introduction of air to the can is at least part of what causes the PR to go bad and not just age?
Any comments? I know old PR has been discussed but maybe not "unopened" old PR.
Alice
 
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When I purchased mine from a local company, I asked how long they had the PR in stock. He had it for a good while but had just opened it. He stated that the shelf life started from the date that he opened the container. This checks with what you discovered then.
 
One of the reasons PR is pourable is that it contains about 50% styrene monomer - a volatile liquid also responsible for the odor. You can thin PR with styrene monomer and that is what's typically done when it is used for spraying fiberglass. Perhaps it is just evaporating over time in the open can and possibly could be rejuvenated by adding styrene monomer.
 
Very interesting. I did store the cans in the basement in a metal cabinet so the temperature was neither hot or cold.
I wonder if those products that one can buy to displace the air in other items such as finishes etc.. to keep them from drying out would have any effect on the PR?
When I first started messing around with this,about 3 years ago, I put about a quart of it in a plastic bottle that used to have dry creamer in it. In a couple of weeks being out the porch in the bottle it actually hardened solid without any activator! I live in Illinois so the summers can get in the 90's, but why would it solidify like that? I was thinking maybe it had to do something with the air getting to it because it was in just a plastic bottle not meant for chemicals
I'm thinking if I have any left of this can when fall rolls around I will try putting it in a smaller metal or glass can or bottle without much air room. Hopefully this would keep it from going bad.
PS, Bruce, where would one get styrene monomer?
Alice Elody21
 
elody21 said:
Very interesting. I did store the cans in the basement in a metal cabinet so the temperature was neither hot or cold.
I wonder if those products that one can buy to displace the air in other items such as finishes etc.. to keep them from drying out would have any effect on the PR?
When I first started messing around with this,about 3 years ago, I put about a quart of it in a plastic bottle that used to have dry creamer in it. In a couple of weeks being out the porch in the bottle it actually hardened solid without any activator! I live in Illinois so the summers can get in the 90's, but why would it solidify like that? I was thinking maybe it had to do something with the air getting to it because it was in just a plastic bottle not meant for chemicals
I'm thinking if I have any left of this can when fall rolls around I will try putting it in a smaller metal or glass can or bottle without much air room. Hopefully this would keep it from going bad.
PS, Bruce, where would one get styrene monomer?
Alice Elody21
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The resin automatically goes bad after a certain amount of time due to the promoters used in the resins. Cobalt is the most common. You can extend this for a small amount of time with proper storage, but nothing is going to keep it going forever. Sytrene monomer will not help at all.
 
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