A question about shelf life of paint?

as said throw it out. good thing is generic acrylic enamel hardener is relatively cheap

 

To add to an old post, I've had some for at least 15+ yrs and after shaking they still work great.




and use an older Harbor Freight air powered paint shaker.

 

A few years ago Bill Hines built a clone of his Lil Bat 49 Ford custom, and painted it with black nitro lacquer he had on the shelf for 50 years.

Around 1970 I bought 2 shelves of paint at an auction of a defunct Chrysler dealer. 1 shelf of enamel in quarts for $5 and a shelf of acrylic lacquer in pints for $2. All previously opened, leftover paint. After throwing out the spoiled and hardened paint, I had 120 quarts of paint. For a while I was painting cars and pickup trucks for $65 for a complete paint job. This is how I learned to paint cars.

I had some of that paint around and used it around the shop for another 10 years. It was still good, most of it.

BUT I would not do a good paint job for a customer using old paint. Too much at risk. A cheap job with no guarantees ok but not if the guy was paying big $$$ bucks.

Or if I was painting something for myself I would be a little chancy.

 

Big difference between old enamels and old lacquers. Old lacquer can be completely remelted if it hardens, and used. Enamels, once they start to thicken up, can be problems. As said, old hardener, if opened, is no good after a few weeks. Even old unopened cans I'd inspect. Look for tiny crystals forming. If it has them, it is probably no good, not worth the risk. Ever try to remove enamel that didn't cure properly? Gums up sandpaper, strip discs, awful mess!

 

9 year later and still laughing at $150 reshoot

 

Thanks metl, and all, this container was opened once years ago.

 

So I went ahead and used the old, opened hardener. Evercoat D.O.I. After posting here I spoke to local body guy. He suggested that if it has not crystallised or tuned color it should be OK. In the open container the product poured a bit slow but it poured so in it went. Good results, the paint hardened up as it should and all was well ....
Just so ya know .....

 

I sprayed 50+ year old lead based paint on a daily driver and had no problem. The paint was found in a trucking terminal about to be demolished, left over paint from a long defunct trucking company (Motorways Canada). The reducer and hardener were all included and without mixing instructions i winged it. I would try anything on a piece of tin, just make sure it atomizes and dries properly..

 

some of this I bought 15 years ago and it sat for 20 before that. i'll let you know when I get brave enough to paint something.

 

I always blow in a can when putting lid back on.

Carbon monoxide pushes out oxygen.

In food factory they inject nitrogen to expel oxygen as insurance against spoilage.

 

the problem I have with old paint is the can rusting at the handle then rusting into the can.

 

I try to remember to blow in some Mig mix when I put the lids back on paint material and other such things.

 

if the paint is as old as this thread...yikes!