Using old automotive paint (cans you've had for 15 years)

[jclay]

I have some Nason and PPG automotive base/clear urethanes that are around 15 years old. They're liquid and on a little test panel seem fine. Do you guys have problems with using pretty old urethane paints that look and slosh fine in the can?

[jon_norstog]

John, I had kind of a paint jones and have accumulated a green army file cabinet full of paint, mostly PPG. What I have found is that it stays good as long as the lid is down tight. You can freshen it up with DT thinner if it looks a little thick, but once it goes solid it is gone. What is more problematic is the catalyst. The DBU "candy color" paints, although they are good as long as they aren't dried out, used a catalyst that could go bad over a winter in an unheated garage. The DC series paints, DCU and DCC are good for years and the catalyst seems to have a long shelf life. Some "universal" urethane catalysts will set up solid in the can.

For the most part I buy paint by the pint and measure it for mixing with a tablespoon. That way the paint doesn't get into the groove for the lid. If the can gets crusty there it will leak out the volatiles in the paint and your paint will be dry next time you open the can.

If you have questions about your paint, mix up a tiny bit. If it curdles, don't even put it in your gun/airbrush. If it looks OK put it in the gun and shoot it onto a piece of sheet metal. It will either set up or it wont.

Good luck.

jn

[jclay]

John, I had kind of a paint jones and have accumulated a green army file cabinet full of paint, mostly PPG. What I have found is that it stays good as long as the lid is down tight. You can freshen it up with DT thinner if it looks a little thick, but once it goes solid it is gone. What is more problematic is the catalyst. The DBU "candy color" paints, although they are good as long as they aren't dried out, used a catalyst that could go bad over a winter in an unheated garage. The DC series paints, DCU and DCC are good for years and the catalyst seems to have a long shelf life. Some "universal" urethane catalysts will set up solid in the can.

For the most part I buy paint by the pint and measure it for mixing with a tablespoon. That way the paint doesn't get into the groove for the lid. If the can gets crusty there it will leak out the volatiles in the paint and your paint will be dry next time you open the can.

If you have questions about your paint, mix up a tiny bit. If it curdles, don't even put it in your gun/airbrush. If it looks OK put it in the gun and shoot it onto a piece of sheet metal. It will either set up or it wont.

Good luck.

jn

Thanks for the tips Jon.

I must be tuned into your wavelength 'cause I do the tea/tablespoon thing into graduated cups, I don't cross contaminate them and I hammer the lids on. I've been testing my paints as you noted, too, and observed the same thing. Mixed up the "vintage" Nason Amber Fire with several activators, and one panel without, and confirmed that use of the Nason Select Clear activator doesn't muck it up and seems to work; it's definitely not compatible with a couple of other activators I have. I shot the frame with Nason Ful Poxy primer, then the Amber Fire + Select Clear activator, and then clear coated with PPG 2002. It looks pretty good.

I also got hooked up with the local PPG sales/tech rep who's a friend of a friend and an old bicycle aficionado and, long story short, he's shooting the other Rustoleum Fail frame weekend after next in a proper spray booth. I have a fresh pint of orange metallic Omni Plus for that. He's supplying all the other components; I just hand him the prepped and ready frame (just in time delivery after blasting) and the can of base color. It will be such a treat to not be working within an aerosol bomb or poisoning the atmosphere. Apologies to Humphrey Bogart but I'm hoping this is the beginning of a beautiful relationship!

48706304031_e15b4e6cce_o.jpg

And so the Rustoleum debacle comes to an end; lesson learned.

[Andrew R Stewart]

John- That second to last line bears repeating in another way. "Take care of your painter" as they make or break what others think of your frame work. (While I sort of knew this from the beginning it was Doug Fattic that drove it home for me. ) Andy