# Finishing MDF edges



## PRGDesigns (Jan 25, 2012)

I cut a number of shapes out of the Plum Creek Premium MDF. When I try to paint the edges, the MDF appears to absorb the primer / paint like a sponge. I am seeking a cost effective and efficient method / product to produce acceptable painted edges on MDF.

I currently use Kilz oil based primer spray paint followed up with various brands of spray paint for a finish coat.

In my inquiries to date, I have learned of the latex caulk method and the drywall mud technique. Any additional information you can share on these techniques is much appreciated.

Thanks in advance for any consideration you can give this matter.


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## Sawdust4Blood (Feb 16, 2010)

I know guys that use auto body filler (aka bondo) for a hard smooth surface that paints or lacquers well.


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## firefighterontheside (Apr 26, 2013)

Mix up some glue and water and paint it on the edges. Not sure of the ratio, but guessing half and half.


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## bondogaposis (Dec 18, 2011)

I use drywall joint compound.


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## Flipper01 (Oct 30, 2014)

Sawdust and Titebond or your favorite glue. Hard spackle knife and press hard into the edges. Let dry overnight, sand smooth and prime and paint. Never failed me in 30+ years.


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## NoThanks (Mar 19, 2014)

I've used everything mentioned above, and in my opinion it more work than it's worth. 
The best product I have used has been pre-cat undercoater/primer/surfacer. spray on a couple of coats, sand real good spray on one more coat and sand and it's ready for paint.
I believe the trick is sealing the fibers deep into the edge so that when you sand it closes all the ends and smooths it up. 
Problem with bondo is it's harder than the mdf and is to hard to sand off, 
and the taping mud or spackle or other fillers just get sanded off after putting it on, they don't really seal the edges.
Anyway to each their own but that is what works excellent for me. JMO


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## SierraRick (Sep 2, 2014)

> I ve used everything mentioned above, and in my opinion it more work than it s worth.
> The best product I have used has been pre-cat undercoater/primer/surfacer. spray on a couple of coats, sand real good spray on one more coat and sand and it s ready for paint.
> I believe the trick is sealing the fibers deep into the edge so that when you sand it closes all the ends and smooths it up.
> Problem with bondo is it s harder than the mdf and is to hard to sand off,
> ...


+ 1
Me too.


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## wseand (Jan 27, 2010)

Shellac…


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## randy5566 (Nov 10, 2014)

Problem with bondo is it's harder than the mdf and is to hard to sand off, 
and the taping mud or spackle or other fillers just get sanded off after putting it on, they don't really seal the edges.???

aaaaaa


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## doitforfun (Dec 31, 2013)

+1 for joint compound. It's cheap and easy to sand. Hand sand it and it will hold primer like crazy.


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## bigblockyeti (Sep 9, 2013)

I've tried too many different methods and found it easier to just attach a strip of whatever hardwood I have laying around to the edge. It's much faster and far fewer headaches.


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## putty (Jan 1, 2014)

Someone on LJ recently recommended a 50/50 mixture of yellow glue and water. I tried it on a recent project and it worked great. I just smeared it on the edges with my finger. In the past I have tried drywall mud and caulk. I was surprised how well the dried glue mixture took paint.


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## roman (Sep 28, 2007)

I use Drydex, its a pink drywall touch up compound, goes on pink, dries white. Sand and re-apply until edges are smooth


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## PRGDesigns (Jan 25, 2012)

Thanks to all who responded. I will try a few of these suggestions to analyze what works best for my situation.

FYI - I have hundreds of these pieces to potentially seal the edges, so an efficient solution is essential.


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## dogmir (Dec 31, 2012)

I have used various products like Drydex and other compounds. Although it works they can be time consuming. I like to use Zinsser BIN Shellac based primer. It stinks and will make you loopy so I wear a respirator. Goes on and dries insanely fast which is great cause you can get a few coats on. I then use a hard sanding block to finish. That said I usually just do the whole piece with this. I know they make it in a aerosol can and I hear it sprays like a dream out of a gun. I have not tried either of those. I usually use a brush or roller.


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