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I am painting MDF with rounded edges, and the faces take the paint well but the rounded edges are absorbing the paint to where you can't tell I even painted them is there a product I should be using first to seal the edges so the paint won't be absorbed.

any help would be appreciated.

THOMRIDER wrote:I am painting MDF with rounded edges, and the faces take the paint well but the rounded edges are absorbing the paint to where you can't tell I even painted them is there a product I should be using first to seal the edges so the paint won't be absorbed.

any help would be appreciated.

Tried shellac?

Use glue sizing. Mix water and carpenters glue to a slightly thicker than water consistency. Paint it on and allow to dry. then sand with 120 or higher to a smooth finish. 180-220 would even be best. Then test the paint. It may take 2 coats but this is a foolproof method once you get it down.

THOMRIDER wrote:I am painting MDF with rounded edges, and the faces take the paint well but the rounded edges are absorbing the paint to where you can't tell I even painted them is there a product I should be using first to seal the edges so the paint won't be absorbed.

any help would be appreciated.

In January, 2009 I made 20 vent covers for the skirting around my home. Made 5 from cabinet grade plywood and 15 from 1/2" MDF. The finishing was a good coat of "Kilz" sealer. (white paint stuff) and then several coats of house paint.

The plywood ones have all separated between plys, but the MDF ones look as good as new! Yes, it's time to make 5 new vents. All of the MDF vents were subject to all weather we have. The MDF held up very well so far.

The photos don't show a real good view of the edges, but there are edges throughout the vents.

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For outdoor use you should use MDO, also know as Sign Plywood. It should last decades outside, and paints great.

Something is wrong. Are you sure you are using MDF and not particle board. MDF should not absorb much.

In fact I have routed MDF to the point of having burnished edge that was shiney.

I do paint MDF and never have I had a problem of it drinking in the paint on the edges. That is why I say something is wrong.

I used MDF for a desk for my grandson and I knew I was painting it so I routed the edge so it was burnished to the point of being shiney and painted it. The finished top looks like a one piece sheet of polished plastic.

MDF edges will absorb oil but again no more than the surface.

The MDF product by definition is dense with glue binder that holds the wood particle together this product does not absorb paint.

Particle board will suck up paint, oil, water, you name it like it is going out of style.

Ed, all I can tell you is what the label at the store said 3/4 MDF. It's brown and very smooth. So
I think its MDF

I always apply a primer to MDF (Medium Density Fiberboard) before I paint it because the end grain does absorb more paint than the paper surface. But if it is to be used outside where it will be exposed to water or moisture, you should use MDO (Medium Density Overlay). Will last what seems like forever even when the paint wears off. Not so for MDF.

I was making some art projects with MDF, Thanksgiving Turkeys, and I could not get the paint right. My artist painter friend completed the first one for me my using two coats of shellac and then painting over the now totally sealed surface.
As mentioned by others: shellac

I've used shellac and also used the glue idea mentioned before. Depends on the use. MDO is great if you can find it. Another option for extreme situations is to use resin. MDF soaks it up great and it wears like iron. It also seals the ends just fine. So that's three solutions that work well - I pick the right one for the use.