I purchased a Tikkurila Optiva Primer(eco) to prime a painted wall. When I started to apply it to the wall it was so thick that my roller just slided across it. I managed to get going, but the end result was bad. The coat was uneven, grainy and I could clearly see the old paint through it.

Looking up how it's done on Youtube, I noticed how everyones primer applies smoothly and evenly. Could there be something wrong with the primer I purchased? The primer was kept in a cold room overnight(around 8C/46F), could the temperature damage it? Getting it back to room temperature improved things a bit, but it's still grainy and uneven.

Will an uneven and grainy primer affect the end result?

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  • Wow. Something is definitely wrong with that primer! Was it properly mixed by the seller in a machine and by you? It almost looks like you got a can full of primer colored water...like someone filled a used can of primer with water and returned it to the store and you were the unlucky buyer... Did it have enamel or glossy sheen? Was the surface of the walls properly cleaned before painting? Sorry, but all these factors could affect your painting outcome. To fix this, you'll have to paint another/more coat(s) of primer. You should get a gray primer since you're covering a dark color.
    – DAS
    Commented Feb 11, 2021 at 8:43
  • So the primer was at a temperature of 8 deg C, and you wonder why it was thick? Do the instructions mention any ratios for thinning?
    – Solar Mike
    Commented Feb 11, 2021 at 9:10
  • We mixed it as much as we could. It got thinner when we warmed it up the next day, but the result is still not great. The wall was sanded and cleaned before priming. At the time of applying it was back in the room temperature for more than 2 hours. Could it be permanently damaged by the temperature? Nothing about the thinning on the package.
    – Armands L.
    Commented Feb 11, 2021 at 12:52
  • I appreciate the quick acceptance. However, you may want to wait a bit to see if others chime in with other info.
    – FreeMan
    Commented Feb 11, 2021 at 14:50
  • What does "We mixed it as much as we could." mean exactly? Your arm got tried after 30 seconds of stirring? You opened the can and swirled it around cautiously as to not spill any paint? You played catch with the full paint can for 30 minutes? Something else?
    – MonkeyZeus
    Commented Feb 11, 2021 at 17:07

1 Answer 1


If the primer or walls were outside the temperature range specified on the primer can, it's hard to demand the primer to perform to spec, and any number of poor results should be expected.

Despite having mixed "as much as we could" if it was still cold, it's highly likely that it wasn't mixed properly. Therefore, what went on the wall wasn't the prescribed mixture of solid & liquid, and, therefore, what's left in the can isn't the proper mixture, either.

It's likely that what's left in the can will no longer perform as expected. Once warmed back to the manufacturer specified temperature range, there's a good chance you'll get a smooth coat if you choose to apply what's left, but it's likely not to cover as you'd like it to.

I'd suggest that this can is now likely a good learning experience.

Cold temperatures will not, in my experience, permanently harm paint. We have what could generously be described as a "three season porch" on our house. It was, for many years, uninsulated and unheated. We use it to store paint, among other things, and the temperature back there has probably dropped below freezing, if not below 0°F more than once, yet paint stored there, once warmed to room temperature, has been applied successfully. It may not have been a "perfect" coat, but it was quite presentable.

  • Thanks for the answer. Manufacturer specified that this primer shouldn't be kept below 5C/41F and it wasn't. However, looks like the low temperature still affected it. A good lesson indeed. No matter what's written on the package, the paint should alway be in room temperature before applying.
    – Armands L.
    Commented Feb 11, 2021 at 14:53

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