Posted by Rick Sacks on January 17, 2002
SarahSeems like more frequently than ever before, the stuff in the can is having a shorter shelf life. Adding enamel reducer solves the problem as a short term solution, but after doing that a few times to the same can the paint properties are altered.
Sealing the can air tight never seems to be an option.We have always just removed the skin and started cooking.
What do you do?
Mike JacksonI started noticing this about twelve years ago. Used to be we left colors in tin cans and let them skin over, removed the skin and away we went. Then the paint started gelling more and more without skinning. I think it has to do with synthetic type oils used now?
Rick SacksHi Rick,
I could be wrong on this, but I seem to remember someone telling me that gelling paint "could" be caused by paint that has frozen at some point in the past. Right now, it is probably -5° outside to start the day here. I know some of the cans of paint sit in a truck, outside of the warm UPS buildings in the Winter, waiting for delivery the next day. Lately, however, it is hard to get paint through UPS, so more of it comes to us by Freight truck. Though some of those cans of paint can suffer from freezing, most of our orders placed in Salt Lake get here the next day and it doesn't appear that they set too long in one place.
Like I said, it might not be the case with your paint, but there is really no telling how the paint got from the factory to your distributor.
Just a thought,
Mike Jackson
Mike JacksonI doubt freezing to be the problem here. It neither freezes here or at the suppliers where I get it from. They rotate inventory quickly and if they got stock shipped in the warmer months it could not have frozen in the trucks. Good thought though.
SheilaHi Kent,
Maybe you could spell out the properties of paint that has been frozen? I'm sure that has been studied by the paint industry.
Thanks in advance,
Mike Jackson
This is not exactly, what you are discussing here, but I could not find out how to add a new question, so I am sorry for the inconvience.
Kent SmithMy question:
I had a can of paint to freeze. I forgot and left it out in the camper, during the winter. I mixed and mixed and mixed it, but it will not go back to what it was. Is there anything/substance, you can add to it to possibly get it back to being usable? I had it specially made and, the place I got it, missed it by a smidgen, so, I am not sure If I can get the color that I now have.
Any help, be it good or bad, would be helpful.
Thanks,
Sheila
Jeff LangSolvent based paints are rarely effected by freezing. What can happen is if the paint is frozen solid for an extended period, a freeze dry effect occurs in the can but would be noticed immediately when the can is opened. The paint becomes a solid in the can not a gel.
Waterbournes are subject to freezing issues. When frozen, the ingredients seperate and the cure process begins in some components. Once thawed, the paint can never be reconstituted completely and the amonia based dryers will evaporate off the top in a matter of minutes.
Gelled paint in the can is a symptom of accelerated curing process. Because the dryers are synthetic now, the window for shelf life has been shortened a great deal over what it used to be.
By the way, alkyd is a synthetic oil that was developed in the 30's and has changed little since then. Sythesized pigments can also be culprits in early curing. Many of the paint companies change pigment suppliers as often as most people change their underwear. This is an effort to control costs, maintain color ratios and maintain EPA or AQMD compliance as well. As an example, a can of black lettering enamel from batch to batch will not necessarily be formulated alike. One may have a certain pigment, dryer, alkyd resin (there are over 100 types), formula solvent, tail solvent and a couple of proprietary ingredients. The next batch may have any combination of these or all may be entirely different. Just using the base ingredients there are then, 5040 possible combinaitons.
The paint chemist's only duty is to ensure that the paint applies, drys and adheres "funtionally" the same for every batch. All this means, assume nothing about product, "use as fresh a material as you can and rotate your stock frequently". This quote is from a Sherwin-Williams manual that appears to be from the early 50's. word to live by today too.
CarolRick,
I do pretty much the same as you described. But, I have thought of finding a supplier of glass marbles or something similar to fill the can back to the top after paint is removed. The cost would have to be inexpensive.
I thought this would eliminate the air pocket, & also act as an agitater when the can would be shaken next time(like a spray can).
Just an untested idea though.
I have exhaled into cans to remove the oxygen, but I had not figured if it really helped.
Jeff
What would happen if you/we put waxed paper over the top of the remaining paint before closing the lid?
Denver Chapter of the Letterheads