Do artist oils go bad with age?

Well, I cleaned off the dry paint around the tube nozzle and then squeezed a couple of mls of paint onto a piece of newspaper.  Consistency of the paint at the end was clearly different from the start, so I think that the paint had started to cure at the top of the tube.  Maybe I didn't seal the tube tighly, but now it suspends very nicely inmineral spirits. 

Looks like it may have been my mistake, but thanks for all the suggestions.

Don

Manstein's revenge

I knead my tube at least once per day to keep it fresh...

Well just be careful not to squirt paint all over your keyboard.

HawkeyeHobbies

Try kneading the tube to reblend the contents. Has the tube frozen or been subject to extreme temps, this will cause the components to separate and crystalize.

zokissima

Can you elaborate a bit on what you mean by "the solution turns grainy"? Do you mean that when you stop stirring, the paint will still separate from the thinner into very very fine grains? If you stir it again, does it stay grainy, or dissolve, then again returns?

Yes, that's what happens.  It's more of a pigment suspension than a solution and upon standing, the pigments settle.  I wouldn't call them very, very fine grains.  Recently, they seem to be larger flakes that make applying a nice even wash more difficult.  Make sense?

Don

Can you elaborate a bit on what you mean by "the solution turns grainy"? Do you mean that when you stop stirring, the paint will still separate from the thinner into very very fine grains? If you stir it again, does it stay grainy, or dissolve, then again returns?

I thin mine with mineral spirits, and it behaves as such often. It is not an issue however, I'll just keep stirring the paint and thinner, and there are no issues. Its not as if the paint is turning grainy and immediately curing...

Try kneading the tube to reblend the contents. Has the tube frozen or been subject to extreme temps, this will cause the components to separate and crystalize.

Sometimes...

I've had most of mine since before my enforced break, about 9 years+, and i haven't had that problem. So you should be ok. Ye, try taking some off the top and see how it goes.

Thanks for the replies.  Thought it was unlikely that they have a limited shelf life.  This tube I've had for 3 years.  Might just be that it has started to cure.  I'll remove some and see if it behaves differently. 

Don

They can, but it probably takes an AWFUL long time...

not that ive encountered, how old is it? sometimes if they get some air in them they go grainy.

At the moment im thinning mine with a product called "liquol" its a step between oil and turps. But im also using them for actual canvas paintings lol.

All i can think of is the paint in the tube has started to cure or your getting the crusties from the top of the tube in there.