Model Railroading > Acrylic Paint Shelf Life

I have a large collection of Badger and Polly Scale Acrylic paints that are probably anywhere from 15 to 25 years old at this point. Some have been opened, many have never been used. Can they still be trusted or does the paint break down over time and suffers quality? I don’t want to try and use them for projects if the results won’t be good.

Mike Peters
Brentwood, MO

Posted from iPhone

The Polly Scale is probably OK. It may need water.
The Badger is iffy

I would test any of it before committing to a model. An important project should have new paint.

Polly Scale water-based acrylics may or may not be OK. I've had open bottles way younger than yours where it first appeared to still be in liquid form, but had a mass of hardened sludge at the bottom that could not be stirred. Then again, I've had other open bottles that turned into a thick goo but were still stirrable, where I could slowly add distilled water to bring them back to a more normal consistency where they then seemed to apply fairly normally (your mileage may vary). Other open bottles seem to still be like new after quite some time. Really a wonderful line of paints that I miss greatly! I've only more recently started using Badger Modelflex which does seem to be a formidable replacement, though I haven't had them long enough to see how long open bottles last by comparison. Also, I agree with the previous reply that recommends using a newer bottle on an important paint job. Even if a bottle can sometimes be rehabbed to a normal consistency, there my be some unrecoverable degradation/change that may have occurred when it, say, turned into a sludge.

 

So long as the paint has not solidified to a large degree, it should still be salvageable. I have a paint mixer that is really a repurposed martini mixer, it can do wonders for reviving old paint. Here is what I use, but the plastic depresser for the on switch fell off, so I glued on part of a sanding stick to the metal tab to use as a button.

https://www.micromark.com/Cordless-Mixer-for-Model-Paints

Ted Curphey
Ontario, OR



Edited 1 time(s). Last edit at 09/18/23 19:43 by funnelfan.

I've got some acrylic paint by pro color that's over twenty years old and it's still usable.

Have a look/see to check if they're still usable or recoverable by adding solvent or water (depending on whether they're solvent or water based). Acrylics don't react with air/oxygen in any way so if they have gone solid it's because the solvent/water has evaporated or the pigment powders have flocculated/agglomerated.

The biggest difference in shelf life is the bottle.   Badger insists on using plastic bottles which "leak" molecules and the paint will harden sooner, Polly Scale used glass bottles with metal caps so it will last much longer.   If the paint is still liquid then you can use it.    You can thin it with water but that is not the best idea.    Badger makes thinner use that.   For Polly Scale use Testors water based paint thinner.    The same problem shows up with Tru Color, which is not water based but is in plastic bottles and will dry out even if never opened.    Some modelers will store their water based plastic bottle paints in large air tight containers with some water inside the container to help stabilize the leak down process.

ATSFSuperCap Wrote:
-------------------------------------------------------
> The biggest difference in shelf life is the
> bottle.   Badger insists on using plastic
> bottles which "leak" molecules and the paint will
> harden sooner, Polly Scale used glass bottles with
> metal caps so it will last much longer. 

This is a misconception. Water based paints are often put in plastic containers but water based paints tend to be less stable over the long term, regardless of container. This is because of the inherent difference between pigment stability in water and oil based paints (water needs surfactants and other additives to initially stabilise the formulation but these aren't so effective in the long-term). So if they harden sooner it's not because plastic bottles 'leak molecules'.



Edited 1 time(s). Last edit at 09/19/23 11:40 by exhaustED.

I've had bottles of Polly Scale that are at least 15 years old that I've successfully revived just by sticking in a few glass beads or BBs to agitate the contents.  Shake vigorously, and voila!  Your paint is good to go.. thin before spraying as usual.  

The only other issue I've encountered is that some bottles of Polly Scale  are very difficult to open after many years, even after heating the lid and bottle in hot water. I'd attribute these bottle opening issues are due to dried paint inside the bottle cap.  

Cheers,
Harry