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Temperature for painting mdf

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Forum topic by EthanC posted 01-15-2011 10:23 PM 1530 views 0 times favorited 9 replies Add to Favorites Watch
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EthanC

34 posts in 2731 days


01-15-2011 10:23 PM

Topic tags/keywords: paint mdf temperature

We’ve had a string of cold days in Houston (lows in the 30s) and I painted some mdf cabinets before assembly with oil based primer and then two coates of semi gloss latex paint. I put the last coat of latex on about 3 days ago. Everything seemed find but I was checking out the pieces today and noticed that I can scratch the paint off with a fingernail and hard pressure. I didn’t think latex should scratch that easily and I tried to scratch some other semi gloss latex projects I’ve painted (in warmer weather) and could not.

I know (now) the can says don’t apply the paint below 40 degrees, but I’d like to not have to dump this project. One thought is to wait it out. Does anyone know if the paint will eventually harden? Would it help to bring the pieces indoors for a couple of days? I guess I could also top coat them with some poly when it warms up, but don’t really want to. Thanks


9 replies so far

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GaryL

1094 posts in 2291 days


#1 posted 01-15-2011 10:54 PM

Was your primer completely dry before topcoating? This would take longer to dry in cooler temps.
I would wait it out on the latex to give it more time to dry and “cure”. Can you move it to a warmer area?
If it continues to want to peel you may have a “gasing out” (slang) problem. This is where a solvent based product is topcoated too soon or too heavy and the solvents are trapped under the surface creating a very weak bond.
Hopefully it will dry out with some time and warmer conditions.
I’m a believer of oil primer=oil topcoat and water based/latex primer=latex topcoat to avoid any problems.

-- Gary; Marysville, MI...Involve your children in your projects as much as possible, the return is priceless.

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EthanC

34 posts in 2731 days


#2 posted 01-15-2011 10:58 PM

Thanks, the primer seemed dry to the touch and it was dry enough to sand so I assume it was dry. I think i’ll wait it out and move the parts inside to see what happens. I should have used oil based topcoat, but this is a scrap wood project so I went with some latex I had laying around.

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Steven H

1117 posts in 2521 days


#3 posted 01-15-2011 11:00 PM

What brand of primer and latex you are using?

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EthanC

34 posts in 2731 days


#4 posted 01-15-2011 11:07 PM

Kilz interior oil based primer and Behr (home depo’s main brand) Semi Gloss latex

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hObOmOnk

1381 posts in 3588 days


#5 posted 01-15-2011 11:21 PM

Water-based paint on top of oil-based primer?

-- 温故知新

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EthanC

34 posts in 2731 days


#6 posted 01-15-2011 11:26 PM

Yep, it says right on the can of primer that it can be topcoated with latex or oil based paint. I’ve done it many times before when using mdf since you cannot use water based primer on mdf. That’s why I think the problem here is the temperature. It probably has not cured yet. It takes some fairly strong pressure with a fingernail to sratch it, but this will be a piece that will take some abuse.

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Steven H

1117 posts in 2521 days


#7 posted 01-16-2011 01:48 AM

Yes Temperature is part of the problem and second problem is the products it self.
You are putting Crap and Crap= Crap finish.

Use Zinsser High Hide Cover Stain Oil Base Primer Sealer.
And Sherwin Williams or Ben. Moore next time.

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GaryL

1094 posts in 2291 days


#8 posted 01-21-2011 12:45 AM

The Kilz is a pretty fast drying product. I’ve used it alot for the stain blocking properties, then topcoating it with latex with no problems (walls, ceilings, trim).
I think the temp is the culprit. How did it go after you moved it to a warmer climate?

-- Gary; Marysville, MI...Involve your children in your projects as much as possible, the return is priceless.

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EthanC

34 posts in 2731 days


#9 posted 01-21-2011 04:27 AM

The paint has definitely hardened in the five days since I brought the parts inside the heated house. It has also warmed up a little here. I think one more week and they will be cooked perfect. I’m going to topcoat the latex with poly anyway, just to be safe.

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