Do enamels have a shelf life?

Most likely you're not stirring the bottle (as opposed to shaking the bottle). There are pigments sitting at the bottom of the bottle that needs to be stirred up.

I've got enamels from 20 + plus years and are still in good condition.

Stir, stir, stir... and then stir some more. A year old is nothing for shelf life for enamel paints. Like Blacksheep I have some paints in my stores that are well over 20+ years old and still work great. Of course those are Humbrol enamels. Testors small paints will often last for many years as well. Their Model Master line though tend not to last so long. Gloss paints will tend to thicken up and dry out sooner than flats. The biggest thing is keeping them all sealed properly for a good long shelf life.

Second 214's post, a paint system is composed of many ingredients, solids, solvents and stabilizers. Even when purchased new off the shelf, they must be stirred completely until no thick globs of it remain on the lower part of the stick. 214 is right, when properly sealed I have had Model Master enamel store for many years, but the lid seal has to be perfect or air does it in.

I never shake the bottle, that only goobers up the lid threads and seal insert. That ensures the bottle will not seal properly again. I use a small dental spatula for initial stirring, or piece of sprue, I avoid wood, since it could introduce particle contamination. When thoroughly stirred I use a Badger mixer and give it a good blend. Then, in order to transfer to a separate bottle for thinning and further mixing, I never pour over the bottle side in order to keep the bottle threads clean. For transferring I use a syringe or even a straw, with a thumb over the end it will hold paint inside for transfer.

So the answer to the question of enamel storage, relates mostly to the condition of the bottle seal. Keep the cap and bottle threads clean and it can be stored for a very long time. If some paint should still find it's way to the outside anyway, be sure to completely clean the threads before re-capping. I'll bet if you go back to that bottle you checked, then give it a quick stir, you'll find lot's of thick material at the bottom of the stick. Hope this helps.

Patrick  

In my experience, MM enamels don't last long once the bottle is opened.  I've never had a bad experience with other paints.  I seal paint bottles with plastic wrap so that no air can get into the bottle.

Well I already see one thing I've been doing wrong, I've always shaken the bottle and some of the threads have gotten messed up.  Yet again I've learned from this forum.  Thanks for all the great info.

Never shake but stir that paint till everything is mixed and blended. It may take a couple of minutes but it's very important to get it mixed and blended.

I have a few MM enamel bottles well over 25 years old and Humbrols over 30 and are still good. On the other hand, I just had a bottle of Testors Gloss White go bad on me and it's a year or two old. I think quality control has taken a dive on the newer made paints.

I'm with plasticjunkie. I, too have MM enamels over 20 years old still going strong. I did have a couple of them (the old ones) went bad on me due to cap not on tight though.

Chrisk-k

In my experience, MM enamels don't last long once the bottle is opened.  I've never had a bad experience with other paints.  I seal paint bottles with plastic wrap so that no air can get into the bottle.

I concur.  And, I find once mixed with thinner and ready to airbrush, it goes bad even quicker.  I have a couple times decided to save my airbrush bottles containing a certain color because my next model would use that same color.  By the time the second model was ready for paint the stuff had gone bad. I have learned to mix up a new bottle for each project (and of course for each color).

Don Stauffer

 

 And, I find once mixed with thinner and ready to airbrush, it goes bad even quicker. 

I've not had an issue with any of the Humbrol tins I have. I purchased an older tin from a local store recently, and the binder had almost entirely separated from the pigment, and whatever else they have in the paint. I just stirred until the thick pigment sludge stuck to the bottom of the can dissolved back in to solution with the binder. I find this same tin separates faster than my newer ones do, but once everything is back in solution the paint works great.

I want to thank those that responded to this, I tried stirring and that did the trick.  It's amazing what a simple little difference between shaking and stirring can make.  I had always shaken the paints just assuming that would be more effective.  So when I did that sure enough I did notice a lot of the thick stuff at the bottom and once it was stirred in made a complete difference.  Thanks again for everyone's response.

You're very welcome, Spitfire, glad that it did help out. And thanks for letting us know, these forums are a great source for community sharing of info, I've been helped a great many times by the other members, being so willing to share their experience. Good modeling everyone, and Happy Fourth USA,  in a couple of days.

Avoid fireworks, model building is much easier with all of your fingers. Much better on TV anyway.

Patrick

I wonder why MM enamels go bad so fast.  

After having a couple bad experiences with MM enamels, I bought Humbrol enamels.  As a test, I made a mix of thinned Humbrol black about 50 days ago and put it in a bottle.  The mix is still fine.  

What  about acrylic paints? Do they also have a shelf life?

I find the quality of the painting is improved with stirring rather than shaking, too.  Stirring well seems to mix the paint better.  I go through more stirring sticks now, but that is not a problem.