I have two five gallon buckets of Sherwin Williams PVA Drywall Primer & Sealer which is about a year and a half old. One is a partial bucket and the other is sealed and has never been opened.

I just opened them and they both have two small colored areas separated and floating near the top. One is orange and the other is green:

photo of primer with colored areas

I assumed that it was mold when I opened the partial bucket, but when the unused bucket had it too, I started to wonder if this was normal.

Is this primer bad or can it be used like it is?

  • diy.stackexchange.com/q/18133/46271. It will probably be fine just stir really well before using. See the link for related info.
    – Kris
    May 19, 2020 at 3:03
  • @kris Thanks, but what about the colored stuff in it? If it wasn't for that, I wouldn't have even questioned it....
    – lnafziger
    May 19, 2020 at 4:16

1 Answer 1


Primer-unbdercoat often has a higher pigment content than topcoat paint, this helps it cover marked surfaces better. usually the pigments are a combionation of carbon black and titanium oxide white.

When left to stand the different pigments will separate at different rates giving a mottled result like you show above. just give it a really good stir. Not ten laps with a popsicle stick, a it'll take a really good stir to mix the settled pigment back into the resin. I use a bent wire in an electric drill.

  • 2
    I've taken older paint back to the store where I bought it and they put it on the shaker machine for me. May 19, 2020 at 4:40
  • I have a helix paint stir that fits a 1/2” drill it works well and I fully agree with a good stir.+
    – Ed Beal
    May 19, 2020 at 23:07
  • I have a small one from a coat-hanger bent into a sort of 'J' shape for small cans, and large one from re-bar for large pots. I don't paint often enough to purchase one of those helix ones
    – Jasen
    May 20, 2020 at 0:22

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.