How To Seal & Paint MDF

MDF board is an inexpensive and versatile choice for many types of furniture, as well as a common material used in CNC woodworking and decor, but it can be tough to paint and seal. In this video, I experiment with spray lacquer, shellac, Minwax polycrylic, polycrylic spray, and polyurethane. So which one wins? Watch to find out!
Zinsser Shellac
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Minwax Polycrylic
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Minwax Polycrylic Spray
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Minwax Polyurethane
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Minwax Aerosol Lacquer
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00:00 Introduction
00:38 Types of Sealants
04:06 Applying the Paint
04:23 The Results
07:06 Sealing MDF Edges

[@ronniet906]

Quick, Informative, to the point, and no bullshit talking. Excellent MDF Finish video, Thanks

[@brycejeannotte7699]

I have finished a lot of MDF and I have found that I get the best finish when I use a brush on primer/sealer. After the primer/sealer I lightly sand the MDF to get a very smooth finish. This applies to the top and bottom surfaces as well and edges, if you need them painted. After sanding, wipe down the piece and apply your finish coat. I did some equipment racks and shelves with high gloss black paint and used a 4" foam roller. They looked like they were plastic dipped when done. I find MDF always needs to be sanded a little to get the kind of finish that I like. Painting raw MDF if just a waste of time.

[@SothpawDesigns]

Yup, I realized that I should have sanded. I learned a lot from doing this, now the next step is to get better and finish.

[@SothpawDesigns]

What grit do you use when sanding the MDF?

[@brycejeannotte7699]

@@SothpawDesigns I normally use 150 or 180 in my random orbital sander.

[@mattedwards4533]

Thanks for the experiment!

[@matthyde9705]

Really helped me decide what I was going to do before I painted mdf for the first time building a desk for my son's friend

[@SkittsMcGee]

You saved me so much time! Thank you.

[@djlafg58]

I'm building speaker cabinets and have watched a lot of vids by experienced speaker constructors. A favourite is the Zinsser B-I-N primer sealer when using MDF. This is Shellac based but has other components. There is also a water-based Zinsser 1-2-3. The Shellac-based version seems preferred , with the water-based version not far behind. Finishing paint is usually with Rust-Oleum (furniture paint) spray can. Rubbing down is done several times with increasingly finer sandpaper in the process, building up the paint thickness in layers.

[@riezan]

Thanks. This really helpful

[@brianyoung933]

Thanks for the great info

[@SteveHartmanVideos]

thank you, this is exactly what i was looking for.

[@unicornstudios7836]

Thank you for the video.

[@JulietNorelli]

One of the best KZbin videos I’ve watched. Thanks for sharing and explaining everything so well!

[@SothpawDesigns]

Wow, thank you!

[@jacobthompson4444]

Thanks for creating this video! This is great!

[@SothpawDesigns]

Glad you liked it! Do you have anything to add? I just tried some stuff, not sure that these were the best results.

[@NWGR]

My go-to is dewaxed shellac, 2lb cut. A couple of coats, sand between, sand with 320 before painting. Buttery smooth finish. I mix my own from flakes these days. I like BIN primer a lot too; it's shellac based so it works well with any paint going over it.

[@jsmelvin88]

Filler primer is my go to. Either the Rustoleum 2 in 1 Sandable, or I'll use the MTN based White primer. Depends on the colors I'm painting.

[@overit81]

Great video!

[@SothpawDesigns]

Glad you enjoyed it

[@bobswihart]

I have tried only a few things to seal my MDF. One I tried that you did not in this video was just wood glue and water. It worked well for me on prism cut letters. Not sure how it compares to other things though. I did have to sand still. 😊

[@Grace11523]

thank you

[@SothpawDesigns]

You're welcome

[@Stu81]

Acrylic primer-undercoat, it's what professionals use, only needs 2 coats, it's the only thing I would use on MDF and I've nearly tried every other thing and nothing beats it, machined edges come up super smooth as long as you know how to sand as that is what contributes most to a good finish, I alway pre sand with 400, then sand the first coat with 400 and sand the second coat with 600, never fails.

[@Acreativejourneywithmelissa]

Thank you for your video. I was looking up how to seal mdf and what it would look like without paint. The beginning of your video was helpful, but I was unable to see the end result of the different finishes in the video without paint because they weren't shown at an angle until the last two. Oddly, the poly acrylic spray looks like it was brushed and vice versa. Who'da thought!

[@justinbanks2380]

Very interesting comparison and test. You keep mentioning how flat the colors are in comparison, and while I understand the comparison being made, it should also be noted the paint you used is a matte one. So shininess is actually changing the paint intended finish. But great work. Just adding the note for others. And to help the algorithm.

[@randallsemrau6911]

The Polyacrylic is water based. It raised the wood grain.

[@damianlaymon7246]

Let’s see how this one does!!

[@krisbredwell2644]

I would have liked to see you hit all of those with some 500+ sand paper between coats. You mentioned that. What is everyones thoughs on finishing MDF for outdoor signs? Should I seal over the spray paint? Thank you for the video.

[@JHall-jo9rm]

Question - did you shake each can of product for 2 min before beginning? If not - this affects the consistency/stability of the product significantly. Very interesting how the polyurethane brush on dried almost instantly (crazy!). I'm wondering if applying wood hardener to MDF before beginning to seal/paint/finish it might be a good option? I've used it on one MDF product to stabilize it (very old) before placing a new wood surface over it.. and I remember thinking it would paint nicely (over the hardener). Ultimately, the problem with water based polycyclic sealers is they are not going to be water resistant. Great demo - really helped seeing how the lacquer worked!

[@troybrake5686]

I just dropped 50 bucks at Lowe's i got the spray Shellac, poly acrilic, 2 n 1 sandable and im gonna sand each step to 400-500 grt then im gonna lay my base(?) Then maybe a expoy pour or a triple thick clear glaze over my( don't tread on me) logo that is gonna be on the face of my truck speaker box, this is my first one, wish me luck🎉

[@teardrops7841]

Have you tried a light sanding after spraying the poly and then painting? I’m thinking it would make a smoother finish.

[@robibmw]

The sheen of the sealer shouldnt effect the topcoats sheen, also sealer needs to be sanded smooth before topcoat.

[@DavidSiebert]

Shouldn't you prime, paint. and then add the sealer? I could be wrong but it just seems like a good idea.

[@jimpalmer1944]

Nice job, did not know. Would it have produced a better finish if you sand before applying the paint?

[@SothpawDesigns]

I think it would. I'm trying that today.

[@af2001]

Good afternoon

[@wawoodman]

Like many others, I use BIN. Bot almost anything 3:55 works on the surface. How about sealing the edges?

[@troybrake5686]

Great video, there you go YT, throw this dude a bone

[@SothpawDesigns]

Boom!!!

[@JoeLazzara]

Hi Damian. This video couldn't have come at a better time lol. I'm in the process of trying to figure out how to paint that stuff also. 😃 After its sealed, do you think it really matters whether the paint has primer in it or not?? I'm just wondering if it all depends on the mdf being properly sealed and sanded. Also, do you know which grit to use to sand in between the sealer coats? Great video, buddy. This will definitely help a lot people out. 👍👍

[@SothpawDesigns]

I think that once it's sealed, the primer/paint combo isn't really a big deal, based on other work I've done. The main thing that I'd recommend is to make sure that you clean your workpiece and sand it before priming, maybe even a light sanding after the first coat of seal. I think that's the reason for a little of the grittiness of the finished work. I'm gonna try to refine it a little today and see if I can improve the finished look.

[@JoeLazzara]

@Sothpaw Designs - Woodworking & CNC For Beginners Oh ok, thats good to know then. Hopefully you'll be able to share with us the results after you refine it. It'd be great to see how it turns out and exactly how you did it. 👍

[@Scott60077]

Thanks for the video. Have you ever tried Minwax Sanding Sealer on the MDF boards?

[@SothpawDesigns]

Not yet! I'll need to give it a shot.

[@ExtremeRecluse]

What about KILZ?

[@KingKatura]

I know gel stain can be used on mdf but i wonder what water & oil based stain stains look like just by themselves on mdf?

[@SothpawDesigns]

Not sure. I need to try more options.

[@jfresh2054]

Why would you paint over sealant? Isn't sealant supposed to go over the paint? That's what gives it's durability

[@SothpawDesigns]

The sealant seals the MDF, helping to get a better paint job.

[@mehdinikoozad7068]

you forgot to sand

[@SothpawDesigns]

You're right. I did.