I put a less than dime sized chip in the lower rear side of my Sabre yesterday. BCB says it is clear gel coat with silver flake. I have an unopened pint of clear gel coat that I had purchased from Ranger about 5-6 years ago, and never opened. It is in a can thatis taped around the top, in a gallon zip locked bag that is also duct tape sealed; (their shipping method). Is this still "good to go", meaning I can get silver flake and activation agent? Or, should I get new gel coat?
I would think as long as you have kept the air out and not added the hardener then it should be good.
Usually hardener goes south on you before the resin does.
I'd get some new hardener, mix up a test batch, spread it on something and see if it cures properly. If it does, go to town on the boat!
Polyester resins / gelcoats generally have a shelf life of 12 - 16 months in an unopened can. Most Gel manufacturers will guarantee their resins to be stable for 3 - 6 months after purchase if still in the sealed factory container. That said, some will last longer if never opened, but check for yellowing / rust coloring on white or neutral gel before using.
Sometimes they will start to crystallize, if that has happened you can sit the can in some very hot water and allow the gel to heat up to break the crystals back down to liquid.
Like CC said, the MEKP catalyst will break down, you should always use fresh catalyst, it's cheap and a major contributor of older resins/gels failing when used.
Epoxy resins have a much longer shelf life that polyesters, but you pay for that difference in the initial cost also.
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