Do THIS Before Painting MDF (How To Seal MDF Edges)

Do THIS Before Painting MDF (How To Seal MDF Edges) Don't have the right primer on hand? Here's a quick way to seal MDF cuts before painting to get perfectly smooth finish!

If you use MDF a lot, you'll know that the sides (unlike the top and bottom) are not 'sealed'. When the sheets are cut to size, the fibers along the sides are exposed, and this leaves them vulnerable when exposed to moisture. The raw fibers absorb the liquid and become raised and rough (like end grain on lumber), and this can be a real problem when it comes time to paint. Don't worry too much though, we've got a simple solution for you!

If you're like us, and are more likely to have wood glue on hand than a solvent-based primer- here's a really cool trick to make sure your MDF edges don't swell when you paint them! Simply dilute wood glue in water (2:1 water to glue, or even 1:1), mix it up and paint it on the exposed edge. A gentle sanding before paint (as well as in between coats) will give you a surface as smooth as the face of the MDF.

Looking for more 'infotainment' from the Refresh guys? Follow the links below for more DIY friendly 'how to' instructional videos, as well as tons of satisfying, easy to watch videos on our other social media pages!

[ThekiBoran]

That's old school and it's called a glue size. The old recipe was 10:1, water to glue. It was used to pre treat wood prior to finishing. It helps lock down the wood fibers.

[wombat]

That is awesome! Never heard of that trick to get you a nice finish. Thank you😃

[jamesmazzaferro]

This is legit! Without a sealer to lock the end grain and close at least some of the pores, you have a few cycles of primer/sand/primer/sand ahead of you, not the best medium for the job. When I have made mdf slab cabinet doors in the past, I’d mix up 1:10 or 2:10 glue to water, and paint it on by any means feasible. Ranges from 1” disposable brush, small lead-acid brush, or a soaked rag. It helps to rub the sizing in either slide your fingers one or two passes, or work in briefly with a sponge or rag. The edges dry rough and crisp, easy to sand smooth with 150 or 220

[tonyc]

Yes, that does work and I've used and also I've used Zinsser Gardz primer and it works very well. If you wanted something faster drying, Zinsser BIN works too and is available in spray cans. It's a very fast drying primer.

[thejackofalltrades]

Oh man this is legit. I’ve been using sanding sealer, sand, sanding sealer, more sanding…till I get exactly this. This should save me some time.

[apb]

at 1:12, i cant understand what you are saying, sounds like "sand a coat of wood filler" do you add a coat of wood filler? Can you please explain. thanks

[Wilem]

Does the glue make Tim Hortons Coffee taste better too?

[buffalopainters]

the new school says just get the right primer

[jicseeu]

Yes that's good....but much better is to water down some filler and rub it in and clean off with a damp cloth.

[therightway]

Great until the "music" started.