Latex Paint Too Soft for Bookcases
Acrylic latex paint never gets hard enough to lose its stickiness. Here, finishers discuss other options for finishing bookcases, and how to deal with a unit that already has been painted. October 28, 2008
Question
I sprayed an entertainment center in the same latex they used for interior trim because they wanted to do touch-ups easily in the future. This was sprayed over two coats of primer. A week later, items placed on the shelves are sticking a bit. Does anyone have any opinions? Do I need a longer wait time to use?
Forum Responses
(Finishing Forum)
From contributor D:
The wait time needed will be forever. Semi-Gloss or Gloss Latex never develops what in this industry is called print resistance, it's too soft and the chemicals that enable it to have a sheen tend to promote adhesive qualities. Twenty years ago I made a ton of wooden boxes to help me move my tools. I painted these with semi-gloss latex paint and stacked them on top of each other. I still need to use a scraper to prey them apart. In my application it's sort of an advantage as it enables me to stack them fairly high and not worry about them tipping over. As a bookcase its not good.
From contributor L:
I agree, it never seems to really dry. I always use oil base on latex if the client requires easy touch up or color change down the road. At least the oil base will dry to print free in 7-30 days.
From the original questioner:
To contributor L: Are you saying to apply an oil base on top of the existing latex?
From contributor C:
If you can get a waiver on the "future touchup" problem, I would suggest you spray a clearcoat over the top of the paint job. That will eliminate your sticking problem.
From the original questioner:
To contributor C: A clear coat of what? What will stick to the latex?
From contributor C:
There are many WB clearcoats to choose from for your purpose. One I have used is Target Coatings.
From contributor L:
No, didn't mean to say on top of Latex, meant to say instead of Latex. I only use Latex if backed into a corner. I don't like it. It has one good property, water washable.
From the original questioner:
Just so I'm clear on this, the unit has been primed and finish sprayed in semi-gloss latex paint, delivered and installed. It's 112" X 103" tall. I can't un-paint it or re-spray it in the field. If there is a water based clear coat I can brush out on horizontal surfaces where items will be placed, in the field, and the tackiness is gone, I'm all ears.
From contributor A:
Anything at this point will be an improvement. The easiest thing for you to get is
Minwax PolyAcrylic at any hardware store. If you can find a Sherwin Williams they sell a decent waterborne clear that is ment for brushing. Latex is like the worst coating for bookcases.
From contributor B:
Would an acrylic enamel be better for these applications?
From contributor S:
Actually, the polyacrylic
Minwax previously recommended, or a waterborne poly of most any sort, will work over what you've got now. You'll need to scuff the semigloss with the 3M latex sanding paper (the light green stuff that doesn't load) and paint this over the top of it. Varrithane and everybody else makes what amounts to a waterborne polyurethane varnish and these will get hard enough for this application.
Before you commit make a sample with the semigloss latex that you used. Let this dry two hours, scuff and then come over the top with the polyacrylic and wait a day. Then test the print resistance and go for it if it does what I expect it will.
I actually used this system with some success while building my workbenches back in 1990. I used flat latex paint to get the color I wanted then used a Deft product called, I believe, Armorcoat, which was a waterborne polyurethane over the top of the latex paint and it's still looking good 18 years later.
From contributor A:
I would have guessed a full fill coat of polyester followed by two coats of your favorite 2k. Only a high end finisher like yourself would use latex and cheap waterborne poly on his work bench.
From contributor K:
I've never seen anyone mention Kelly Moore Durapoxy on this board. As a waterbased finish for something like a book case or cabinets, it is hard to beat. In 2 or 3 days it will harden and then it is tough as nails (although for spots that will take extra abuse I topcoat it with Fuhr 255).
While latex will never harden enough if you wait about 30 days then put a coat of Durapoxy on it you may have success because it will dry to a very hard shell. Adhesion test: apply a coat on a test board with the same latex and wait 24 hours - if it will not scratch off you should be good to go. Before painting test for leveling in the customer's environment, you might have to thin it a bit if the place is warm and dry. If done right a brushed coat can look just as good as a spray coat.
Note that this is not a latex material so you cannot use Floetrol. I made your mistake on my first bookcase - I feel your pain. Good luck!
