Paint and epoxy shelf life

[slawosz]

Hi,
I got some International Interdeck paint and bit of coppercoat. I wonder what is their shelf life. Both unopened. International says its 2 years, coppercoat says its 1 year. Both products are around 5-6 old. I wonder if shelf life is a legend or time really makes them worse?

 

[LONG_KEELER]

Interesting question.

With antifoul, older could possibly be better as each year many solvents and biocides are
reduced because of alleged damage to the environment.

Not peer reviewed nor double blind testing, but my test is based on a consistency and a nose test.

 

[DownWest]

Well, I inherited a 50 gallon drum of epoxy a while back. It is currently building two boats and has two earlier ones. It is well past it's 'sell by' but test show still a lot stronger than the wood it is glueing.
Over on the WBF, peeps in the Carib say that the hardeners they get are already browned from age, but do not present a problem.
Shelf lives are an obligatory sticker. Honey has to have one, despite being perfectly edible out of Egyptian tombs.

 

[smithy]

We were given some epoxy paint that was intended to coat the inside of swimming pools. It was a good few years past its use expiry date and no matter what we tried it would not set. I have used SP epoxy that was a few years old and had no problem apart from the hardner darkening.

 

[Stemar]

When you're getting ready to use them, try a little bit. If paint dries and epoxy sets, I'd give it a go. My untested hypothesis is that oxygen causes stuff to go off, so I wouldn't open it until getting close to use time.

At least the copper powder won't go off in your lifetime - or that of your grandchildren!

 

[John the kiwi]

Bottled water needs a use by date in this country. Some of my company's products also require dates despite being absolutely stable solutions..
PC madness which defeats the purpose. How do we now know which use by dates we need to take heed of?

 

[Alfie168]

Bottled water needs a use by date in this country. Some of my company's products also require dates despite being absolutely stable solutions..
PC madness which defeats the purpose. How do we now know which use by dates we need to take heed of?

There is a good reason for the bottled water. Whether we like it or not bottling plants are a significant contamination risk. Then there is the lack of control of storage once it is out of the shop and light/ warmth can and does encourage algal growth. I'm well aware of the joke of putting a six month use by date on something that has spent thousands of years percolating through the planet's rocks, but it's the human intervention that causes the problem.

Back to epoxies and paints. I'd just say do a few non critical test pieces and see how it goes. I had some very expensive German 2 pack epoxy that simply refused to react even when in date. My ancient Plastic Padding polyester fillers seem to work OK forever. You just test as best you can and take a view on whether the risk is worth taking.