How to seal MDF for a gloss finish

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Hey guys! I’m Brad, and I make how-to videos. I do custom painting projects, guitar painting, airbrushing, spray can painting, wood working, and a variety of other finishing work and tutorials. Please subscribe and check out my channel for more!
MDF can be one of the most difficult materials to finish. The problem is that it absorbs paint and other finishing products that you put on it, and it can swell or end up with a very rough, dry finish.
In this video we discuss how to seal it so that you can paint it easily like any other product.
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Behlen website: www.hbehlen.com
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Thanks for watching.
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[@BradAngove]

Heads up guys, the behlen sealer has been re-branded under Mohawk. You can find it through here: www.amazon.com/shop/bradangove

[@rocifier]

It says the product is unavailable. What other products could I use?

[@BradAngove]

You can find it through Mohawks consumer products website instead I believe.

[@daciasdiy1861]

@@BradAngove hey what’s the wedsite to the Mohawk site i really want this

[@BradAngove]

If you go through the link I posted and look up Mohawk consumer products it should be there

[@DRV_Woodworks]

I've used Zinsser B I N shellac based sealer from spray can and seals nice with one coat. 2 coats even better. Sand between coats then top coat sand and repeat. Tried it today and pretty great results with very little effort. Much easier then regular primer which soaks in like a sponge.

[@willbrink]

Looking to paint some MDF speaker cabinets and that will be useful info. Thanx.

[@18deadmonkeys]

I built ten 31" x 96" workbenches with MDF about 15 years ago. Used oil stain and polyurethane to finish the tops. Went through GALLONS of polyu. Those surfaces are almost hard as stone though. Still look amazing.

[@BradAngove]

You basically impregnated them with polyurethane then haha. That’s awesome.

[@sherryleggett1612]

Wow, I would love to see your workshop with all those great worksurfaces

[@chrisgraham2904]

Sanding between coats of clear primer isn't really necessary as long as each coat is smooth and without runs or blemishes. The previous coat is dry to the touch, but is in no way a cured finish. As long as the previous finish has not been left to cure, the next coat should bond very, very well. Always make sure the sealer coats and the finish coats are the same chemical composition -- enamel over enamel, lacquer over lacquer ... etc.

[@jacobbrown1690]

i make high end art decco furniture with mdf/ hdf and use water based high particulate primer. takes 30 minutes to dry. sand then add another coat. protects the mdf from water absorbsion. Then add colour coats and clear coats. you can use all water based paints. There some great acrilic warer based paints and clear coats. i spray the water based clear coats for smoothness.

[@chuckrupert1213]

I have no doubt this would be an excellent finish, but it seems like there are many others that use products that you can buy at the big box stores or even at Walmart. Excellent vid.

[@BradAngove]

Cheers Chuck

[@raj102945]

Thinned water based varnish, two coats. Sanded between coats. 5 coats of water based varnish sanded between coats. Iron on edge veneer, also varnished with several top coats. This gives a really good wood effect that most would never believe cheap mdf is capable of. This video is really useful to learn other methods.

[@patrickmcmahon8218]

3lb cut white (clear) shellac works as a great paint sealer on MDF and Plywood.

[@FreqBand]

Good tutorial. Can I add a few tips ? -- For small pieces like yours, wear a glove and hold the piece in your hand.....and just spray the sides, heavily, several times....until it nearly stops soaking-in. Let dry. It will prob need at least two coats. -- MDF can be very brittle on the hard/sharp edges.I always lightly hit the edges with 220 grit paper, by hand, so there are no sharp edges.. This makes it more durable in the end (less accidental chipping). -- My favorite way to seal the porous edges, is to skim them with automotive polyester filler (Bondo) , then sand. But don't sand through to the MDF, otherwise you are back to where you started. (Skim again if this happens.). Then spray with an automotive "sandable primer"....and carefully sand it smooth with 220 grit or finer.

[@richardkunicki5684]

I used this material purchased in a quart can from Klingspore ($16.99). I used 2 coats sanding in between as shown in the video, on raised panels. I did buy a respirator because the stuff is nasty. China bristle brush. Works great, very easy. Thanks for sharing this process

[@BradAngove]

+Richard Kunicki I’m glad it worked for you. Thanks for watching.

[@cyberspooky]

Best MDF sealer is ceiling white with PVA mixed in , I use 3.5 ltr ceiling white with 500ml PVA , works awesome and cheap 😎

[@Kept_Crude]

Hello Cyberspooky! Which type of PVA exactly do you recommend? PVA Building Adhesive, or PVA Admix Building Adhesive or any other? Please!!

[@1invag]

I've heard using PVA glue can leave a tacky finish, particularly if you use a water based paint anywhere in the process

[@alexcastillo1384]

Drywall sealer pva?

[@FreqBand]

PVA is not easily sandable. Plus using any waterbase on MDF edges, can make them swell. Solvent-based sealers are a better option. Or just seal with shellac.... a few coats.

[@GreatWhiteNiko]

Solvent based alkyd primer - instant dry. (Maybe 60 seconds.) No need to sand edges of sculpted grooves - piles up thick and hides all imperfections, sticking fibers, etc ( (acts like a primer-filler). One fat coat. Accepts any top coat. $40 per gallon.

[@BradAngove]

+GreatWhiteNiko Sure.

[@mr.joshua8664]

This helped a lot. Especially on the sanding part. I am a complete amateur at this and am wanting to work on my skills of finishing with my props using MDF.

[@BradAngove]

Glad to hear that you found it useful.

[@andres.giacomini]

Hello, I paint in MDF with PU paint (monocomponent), this polyurethane is normally applied with a base coat, called "Primer" (like cars), or primer that watching your video would be basically the same, and I tell you more, with 3 hands of first the edges are already well sealed with their respective sanding between hand and hand. The process is the same as car painting. So in my case if you want a good high gloss finish, I recommend a PRIMER, or base paint (not sealer).

[@jojiran]

I dont know if you are European . For some reason this is not done in the US but what you suggested is the best method . I use gray PU sealer

[@andres.giacomini]

@@jojiran I'm not from Argentina. If a one-component base works perfectly, several coats and sandpaper between each coat to smooth and leave a surface as smooth as possible.

[@jojiran]

@@andres.giacomini Are you using oil PU or water based?

[@tleon858]

I usually read the comments to see other helpful tidbits. This is the first time I've seen soo much attention paid to the host's looks. Just to stay in-line with the others, I did find the shirt to be fairly well pressed and nice looking.

[@BradAngove]

Hahahaha thank you for the feedback.

[@uBmaniac]

Just passing by to say I have subscribed because of your consistent effort to reply to as many comments as possible. Even the stupid ones which don't deserve a reply and even a few repeated ones which the questioner could have easily scrolled down to see. It baffles me.

[@BradAngove]

Welcome aboard. I appreciate most of the questions haha. Most of them...

[@Cesarmx14]

You can try solvent base acrilic filler for the edges, it dries fast and is easy to sand, usually a small amount will be needed to seal the edges, for primer I use 2 part polyurethane, sand the mdf with 240 grit sandpaper, apply first coat, sand with 240 grit, apply second coat, sand with 320 grit, apply a 3rd light coat, sand with 400 grit and you are ready for topcoat, it works for me, hope it helps, greetings from México!

[@BradAngove]

Yes, that sounds like it would work well. I'm looking for methods that are quicker and take fewer steps, but I would imagine if you do 3-4 coats before even beginning your top coat it probably looks great.

[@duartepaintinghandymanservices]

I do alot of painting specially on mdf doors, baseboad and crown and i always find that 2 coats 20min apart of kilz original does a very good job on sealing the mdf, I comeback and lightly sand with 220 and than i apply 2 coats of semi gloss and it comes out great

[@BradAngove]

I'm glad to hear that works well for you. I haven't had much luck with the kilz personally. Maybe I'll have to give it another try.

[@superhall229]

Very true. Some people make a mountain out of a mole hill.

[@CGT80]

The key is the oil based primer. I always use zinsser products and have used hundreds of gallons of zinsser cover stain, both oil and water based, maybe even thousands, as a pro painter. The oil based primer seals without swelling the wood and it sands easily to a smooth finish. Oil primer is also key for sealing peeling paint and bad drywall or plaster. When finishing cabinets made from mdf, we also used a lacquer white undercoater taht worked well, but with epa and environmental restrictions, products have changed quickly over the years. In 6 months to a year, a product may not be available or could be quite different, so never assume you are using the same stuff you bought a couple years earlier, even if it is the same label.

[@bp7770]

Sand edges and face with 180 . 2 coats of binz shellac based primer. with a 220 grit scuff in between. Done

[@mikeleahy5283]

What i use

[@UberAlphaSirus]

Barry Penta- Is that zinser bin?

[@browntrout3994]

thx....got a mdf project on the TO DO list right now.

[@UberAlphaSirus]

@@browntrout3994 A little tip for you, the factory edges are tempting to use as a face because they are straight and factory. but they are softer, less dense, have voids and suck paint like a pro. 1/4 inch from the factory edges are sollid. whatever the edge on mdf, long drying time oil based primers wick in and will take 8 times longer to dry so recoating is an endless pain. shelac like zinzer bin drys quick, anything that dries quick but isn't water based is best. Or pay morefor water resistant mdf, the green stuff, you can use anything waterbased.

[@ovais909]

I always used to use body filler but this method looks easy and less messy body filler is really hard to work with , so thanks

[@BradAngove]

You're welcome. I've done it with wood filler and body filler, but I personally prefer just using the vinyl sealer.

[@mpikas]

Kilz works on MDF that will be painted with latex paint, but not under finer finishes. I used some MDF window trim moldings that I had to cut down and modify to fit the space between windows and this worked great. MDF also machines really well so it's nice to make custom parts out of. I've had really good luck using cheap automotive spray primer in a can to seal it up. Cheaper stuff dries faster (about like what you did with the vinyl sealer) and you can often get it for ~$4/can

[@BradAngove]

I used to use the cheap spray primer for my machined MDF parts. The filler primer gets the job done pretty quick. So does a good lacquer sanding sealer if you're doing a bunch of them, but it doesn't build as quickly as the vinyl.

[@NathanNostaw]

A good sealer for MDF is PVA. I have trialed a BondCrete sealing mix, I used a 4:1 water/Bondcrete (external rated PVA sealer/glue). So far I have had no swelling on the test panel which has been subjected to high humidity, heat and rain (sub tropical Queensland Aus) for 4 years.

[@BradAngove]

+AKA Nathan I like PVA; I just find it too slow to work with in most cases.

[@mytuberforyou]

Just get yourself a gallon of the 3lb cut dewaxed shellac that HD sells as a sanding sealer, breeak the edges with a little 120 sandpaper, and apply 2 coats with a spray gun or enven a foam roller or brush. Don't bother sanding anything until it's sealed, in fact, don't even sand until you have a couple of layers of primer on it. When you sand the edges, all you do is push dust into the edges that will contaminate your sealer and keep it from penetrasting as well, just seal the open pores left by your saw cut for best results.

[@BradAngove]

I don’t agree with this, but I’m glad it works for you.

[@nopt1118]

Brilliant presentation; thank you for your time. I’m building a 4m fitted mdf wardrobe and your video couldn’t be more informative. Ps; mind your health though, every minuscule of these chemicals we breathe does no good...

[@BradAngove]

Thanks. I’m glad you found the video helpful.

[@kentklapstein9879]

I have had great result using oil based Varathane. I let the MDF absorb as much as it likes, it takes in a lot. This also seems to strengthen/harden the MDF.

[@BradAngove]

Yes, that can definitely work. It just takes much longer.

[@SimpleChic23]

Hi Brad, Thank you for sharing your knowledge about MDF. I just started my new job as an designer at a German luxury kitchen and home living cabinetry. I am excited about learning more about the different materials we use for our selections of doors. I would love for you to make a video over the differences between mdf, furniture board. What is melamine, laminate,lacquer and what is foil coating?? Thank you!! And I am a new subscriber 😁

[@BradAngove]

I’ll see if I can pull some information together on that. Melamine is just laminated particle board essentially. MDF is basically pressed sawdust and wood glue. I’m not sure what you mean by furniture board. OSB?

[@bigd835]

As of April 2024 this stuff is now going for 24 dollars for one spray can. I dont understand what is going on with the prices of EVERYTHING but if this continues no one will be able to afford ANYTHING. this stuff is out of reach price wise. most of the old oil based sanding sealers are now water based and not as good. our govt has outlawed things that work through regulation. why do people keep voting for this ?

[@MsBrainmuffin]

A really nice way to do mdf edges is buy a roll of iron on veneer edge tape with a more closed grain like maple or cherry, iron on sand the edge seal and paint. The glue on the back of the tape acts like a sealer so you don't need as much spray sealer. It will look beautiful.

[@chrisgriffith1573]

Only way I ever seal MDF is oil based urethane. Reason: Its good for it to soak in, and it forces me to wait for the job to cure and harden the MDF, making the MDF less vulnerable to moisture. After a week, the MDF can be sanded and add just about anything.I actually want the urethane to soak into the MDF, so the first application I put on is thinned out about 1 part thinner to 2 parts urethane. If you are in a hurry... not for you. This is for a quality, long lasting finish that improves the product.

[@Pal.Cockrum]

You can get primers specifically made for mdf or simply use mdf edging tape.

[@kimberleerivera7062]

Thank you so much for sharing! I had no idea! I will be painting some mdf for the first time and this was excellent timing!

[@BradAngove]

Excellent. I’m glad you found it helpful. Don’t forget to wear a mask.

[@MrStreetboy80]

Coolest person Iv seen using a spray can and still makes it look cool when you almost knock It over 😂 I want to vinyl wrap some plywood for a project. I know it’s not going to stick very well. Any advice on that?

[@BradAngove]

The smoother the surface is, the better it will stick. Depending on what grade of plywood you got, if you grain fill and add a couple layers of sealer you can probably get it to stick reasonably well.

[@NeverTalkToCops1]

Superb spray paint can technique, points (many) taken off for avoiding safety protocols.

[@fiver-hoo]

Shellac also works amazing.

[@MWSRD]

For a budget try water based polymer wood glue and dilute with water 1:1 fast curing, sanding between every stage 1 coat. And then any acrylic primer or clear 1 coat it will be "sealed" then at least 2 coats of color and possibly 2 coats of clear gloss to finish build it up D4 wood glue is one solution. Formaldehyde gas will still escape from MDF for upto 6 months after it was cut...... soooo not too good! just a thought.

[@scottgeorge4760]

The company I work for pulls a laminate of various color over M.D.F., a wood wrap . why paint or stain M.D.F. but have it wrapped/foiled in a nylon covering .

[@tranzco1173]

Because we don't work for a company with those resources. Ettore Sotsass designed furniture in the 1980's using the process you describe, and they sell for 30k plus. My dining table is a 1968 Knoll Saarinan, and is laminate over birch ply (with exposed birch ply edging). Good laminate is really expensive, MDF is relatively cheap.

[@vanaranimoodley8955]

Very simple to do ordinary wood filler made into a paste and brushed onto the edges wipe off with a cloth wait until dry then sand with fine sandpaper very light sanding then paint the filler will prevent absorbition

[@lungthumpa]

My recipe for high gloss MDF finish is 3 coats of undiluted PVA, sand with 400-600 grit between coats, works everytime.

[@BradAngove]

I think a lot of people are using PVA for it now actually.

[@bertiebeetle3]

Thanks Brad. I enjoy your vids. Fyi this one jyst popped up on my suggested vids at the right time. Had been wanting to know what to use on mdf. Appreciate you taking time to do this video.

[@BradAngove]

Thanks for watching. I’m glad the timing was fortuitous.

[@davidcurtis5398]

I have been building things for as long as I can remember and always use water based fillers and finishes and I have never - never, never, never, never - have had any MDF to expand.

[@BradAngove]

Congrats

[@griftopherhitchens9926]

I wish I had watched this before my first attempt. I'm getting weird craters on the face surface. Great video - I use Minwax wood filler (Bondo Style with Catalyst) on the edges.

[@BradAngove]

Must have just not filled a few spots quite right. Try going over it with a thin layer of normal wood filler and sanding back.

[@LynnLaceyLLWW]

I have found simple shellac seals MDF quite satisfactory. Dries fast no over spray fumes to breath

[@BradAngove]

I've tried shellac a few times and found it to be incredibly slow. Perhaps we are approaching it differently?

[@BradAngove]

+Jerk Of All Trades words to live/die by haha.

[@scrapper666]

It's "breathe"; a breath is what you breathe.

[@scrapper666]

Shellac dries incredibly quickly unless it's past its best-by date (which should be printed somewhere on the can), and then it can just stay tacky forever.

[@BradAngove]

Shellac takes about 45 minutes dry fully. Not bad, but not as fast as the vinyl sealer. That’s not the issue though. The problem is that it takes a long time to seal the MDF because of how many coats are required.

[@MoOdaso]

Hey Brad.. you should've made a clean up using air blow or wipe before each coat for a good bond of the next coat

[@BradAngove]

To put it bluntly, not I should not have. If anything, waiting a few hours and sanding lightly with 329!grit would have been the ideal option for that purpose.

[@Raul28153]

I use sheet rock mudding compound, works great.

[@sasa1982uk]

Is that jointing compound for tape and jointing?

[@markf.4063]

I use spackle.

[@nassirirani6569]

Thanks, Brad I enjoy your vids becoz very smooth and clear explanation also you are like my favourite character Christian bale that I love him very much so please take care of your self with wearing a mask, buddy

[@bfjohnmark]

Young batman

[@Kyle7K]

I like to use just a good thick, high build polyester primer. Eastwood makes a great rattle can version. Great fill, build and leveling, easy to sand, but takes longer to try.

[@BradAngove]

Polyester is a reasonable choice for sure.

[@LockStoppageSandwich]

Thanks Brad..............Will it take water based gloss finnish ?

[@BradAngove]

The vinyl sealer? I’m not really sure. That’s not what it’s designed to work with, but water based finishes aren’t particularly volatile so it might be ok.

[@valveman12]

Hey, thanks, Brad. I learned something very useful today/

[@BradAngove]

Glad you found it helpful.

[@KilkennyLights]

Thanks for your help. Perfect instructor

[@hj8607]

Using shellac is a much better idea . However, the only surface that needs more than one coat are the edges . Spray very light coats (3-4) to avoid raising the 'grain' of the mdf "stuff" . Each dries in 5 minutes .( light sand edge between coats ) ONE medium coat on smooth surface will seal it to about 95% . Use a fast dry urethane gloss coat and let it dry 24 hrs. to hard sandable finish . Top coat in gloss or any finish desired . Shellac is safe to breath , environment friendly and cheap .

[@BradAngove]

If you’re spraying it, it’s not safe to breathe. Especially depending on what you’re cutting it with. It’s also much slower. Not a worse idea per se, but definitely not better. It all depends on what your priorities are.

[@hj8607]

@@BradAngove the vapors are breathable to extent that they are not highly toxic (a particle mask is always advised ) (alcohol only acceptable thinner) Shellac is a dry fall product and overspray is not a problem . Shellac has no filler value but will out seal anything . The vinyl seal could be an effective filler coat and over a 97% sealed surface it would build faster using less product . ( Not really criticizing your approach its just that MDF , despite all its plus qualities, is a finishing conundrum )

[@mururoa7024]

Use actual MDF sealer (usually white). Doesn't come in spray cans, Use a brush to apply 1 coat, then sand with 320 grit, then 2nd coat and sand again, then spay your lacquer and your clear. Polish and you're done, perfect gloss.

[@BradAngove]

Vinyl sealer is MDF sealer. You can buy it in different formats if you want, but clearly it also comes in spray cans.

[@tony221984inmonroe]

A thin layer of fiberglass resin then sand and paint

[@BradAngove]

I hate fibreglass resin, but that does sound like it would work well.

[@scottwallace4928]

This is what I have done when working with MDF in car audio for 25 years. More work but seals and smooths wonderfully.

[@BradAngove]

Yeah, it seems like an effective option if not an efficient one.

[@damnitdang]

I need to cover a 11cf HT subwoofer enclosure

[@hobohacker258]

Great video. He reminds me of Charlie Day, even in delivery and mannerisms.

[@brettus9115]

Thinned polyurethane glue works excellent. Just keep brushing it on the edges until it stops soaking it up and leave to dry. Especially for mirror finishes but it's to much work for my hidden speakers!

[@sticky59]

Very good tip ...... like 'sizing' a newly plastered wall so it doesn't suck the guts out of the paint when applied. Seals it up and you are good to go.

[@edwaggonersr.7446]

Good information, thanks for posting the video.

[@BradAngove]

+Ed Waggoner Sr. Thanks for watching.

[@myz98f150]

Mdf mdx is awesome Regular mdf seal the edges with a mixture of yellow glue n water than some vinyl sealer sand it apply color top coat it done

[@BradAngove]

+Z Lopez what do you typically use to apply the mixture?

[@myz98f150]

Brad Angove mdf edge

[@myz98f150]

Brad Angove mdf edge with a spray gun ,n spray on the face too

[@JViello]

Great tip, and overall nothing "bad" to say. The only thing I would potentially be concerned about is if you used a solvent or alkaline based finish. It might lift the vinyl sealer.

[@BradAngove]

This sealer is designed to go under lacquer finishes. It actually works great under solvent and/or alkali product.

[@JViello]

Lacquer? Oh wow, considering it was vinyl sealer, I assumed it was a base for some kind of floor wax. So basically one could use this sealer, lay down some lacquer, wet sand and buff to a super deep gloss. Perfect for some audio speaker projects etc. Cool.

[@BradAngove]

Yup, pretty much. Behlen engineered this to be used as the base under their stringed instrument lacquer, which is nitrocellulose based. They work awesome together.

[@alpaykasal2902]

i use titebond or gorilla wood glue, seals it without getting sponged up. Then I paint it with whatever.

[@jrgelat0]

On MDF endgrain? Are you covering the ends with glue then sanding it back? Cheers

[@Cris-ss8tb]

MDF is the devil good line!

[@samgreer8596]

Fantastic video. How would you achieve a black piano gloss finish on an MDF project? What steps / finishes would you use? This video really saved me big time from probably some disasterous results on an MDF project. After the sealing would you use a 1 stage or 2 stage finish? Is there a comparable product to the Leyland Trade acrylic primer undercoat here in the US? Would you use a PVA glue, the vinyl sealer, or an acrylic primer undercoat for a large job? I wish someone would make a vid or series of vids from beginning to end for finishing wood (MDF) Some have sealing, spraying color, or sanding, clearing, sanding, buffing, but never seen the entire process in a video or series of videos. Anyway, thanks for saving me from making a big finishing mistake by not sealing.

[@BradAngove]

+Sam Greer I don't know what leyland trade acrylic primer undercoat is. If I were doing a piano finish on here I would probably use lacquer. I would either start with vinyl sealer or lacquer sanding sealer, then black lacquer, then satin lacquer clear. Once the MDF is sealed, it's just like finishing any other surface. The absorbent aspect of it is dealt with at that point.

[@samgreer8596]

Then that is what I'll do! Thank you. This is my first attempt at this, so do you have a recommendation on the number of color coats / clear coats?

[@BradAngove]

+Sam Greer you just need enough colour to get the opacity you're looking for. Probably 3-4. I'd go with more like 8 clear coats so you can sand and polish if you need to. Lacquer goes on thin.

[@loskop100]

+Sam Greer. I have tried to do a piano finish on MDF a couple of times using acrylic lacquer: six coats of shellac on the edges then a coat of sanding sealer all over. The paint looked fine but when I went to buff it after flatting it with 1500 I think that the heat produced by the buff caused the MDF to sort of delaminate, the surface looked a bit like an ocean swell. In the end I just flatted it with 1200 and sprayed thinner with retarder onto it then squeegeed it with window cleaner followed by a thin coat of colour and hand rubbed it with Farecla 10. Took ages and won't ever do it again on anything larger than a match box.

[@jeffbeck6501]

Try to do that spraying outdoors.

[@chazfaz3595]

Thanks Brad! I'd imagine that you could just do extra of coats of paint - that should eventually fill the pores... Except that the final finish wouldn't be nearly as smooth as would be achieved with a sandable sealer...

[@BradAngove]

You could keep adding coats of paint and keep sanding them smooth and you would eventually get there.

[@chazfaz3595]

@@BradAngove I agree if you pick the right paint to start with. But that paint may not be that great to end with depending on what you're trying to achieve. For outside projects where rain & sun protection is the goal, that single-product process would be tough to find. I've had experience trying to sand slow drying, relatively soft paint types like enamels, and it's not pretty. Trying to sand polymerized coatings, like latex or acrylics, is wa-a-ay nasty. So your filler process seems like the best approach 4 smooth results.

[@iamjackalope]

Not really. You end up with a blotchy finish that you need to wet sand. Another method is to use shellac to seal, then several coats of a high build automotive primer. Dry sand using 600 grit or better of high quality sand paper. Get the good stuff. At that point you could spray enamel if you want to but if you are going to use lacquer as a finish, as I like to, you would then apply the vinyl sealer like you have, dry sand with 600 grit, tint some nitrocellulose lacquer to desired color, tack and spray a couple of coats, tack between coats then wet sand with 600 grit and mineral spirits. After that, tack then spray several coats (3 to 4 wet but not to wet) of clear lacquer, tack between coats then wet sand with mineral spirits and progressively finer paper finishing with 2000 grit. You shouldn't have to sand between coats unless you need to sand out a sag or a run or possibly an flying insect. At this point you will have something that looks dull and not to shiny but that's OK. Now you let it sit for about a month till the lacquer has cured and if you don't have telegraph seams at the joints you finish with 3 grades of polish with a random orbit polisher topped with a good carnauba wax. If all has gone as planed you should have a finished product that slips through your hands when you try and pick it up, literally. If the joints have telegraphed then you will need to wet sand with 800 grit and mineral spirits again then spray another coat of lacquer and wet sand until the joints can't be seen being careful not to sand into the color coats, then progressively higher paper finishing with 2000 grit.Then let it sit again for another month. A couple more tips when working with MDF. Buy quality MDF if you can get it. Not all MDF is created equally. Today's MDF is not as good as it was 10 years ago when they still used formaldehyde based glues so you will find the lesser grades of MDF to be extremely prone to swelling just from moisture in the air. The stuff you get from big box stores is kept in the same isles as their green (wet) lumber and because of this it is likely to take on moister and swell if it has been there for any length of time. MDF from big box stores like Home Depot isn't going to be all that good to start with but it might be all you have access to. In that case try and let it acclimate for a couple weeks inside your house before using it. Using MDF when it has been raining or if it has been humid can be problematic and will lead to joints telegraphing as it drys out and shrinks. One other thing you can do to make your glue joints blend in is use a softer white PVA glue and not the exterior water proof kind like Titebond III that dries to a very hard finish and will make sanding difficult because the glue seam will be harder then the MDF itself and will form a ridge as you sand. It is fine to use if you are going to cover the MDF in a veneer though. It is actually a great glue.

[@blifamansmith3320]

Thank you for sharing. Looked very nice.

[@BradAngove]

Thank you for watching. I'm glad you like it.

[@thethoughtmaster]

I have another technique, same problem though, you could try buffing it.

[@madonnahagedorn5649]

I simply want to seal some fiberboard that go on a storage rack. Can I leave it just sealed without painting it next?

[@BradAngove]

Sure. No really reason not to.

[@sam-ms4hl]

great info budey thank you. helps a lot

[@Website-Developer]

MDF has always been a painters nightmare especially in new construction and most builders and home owners don't want to pay the added costs for this kind of prep work which nearly doubles the finishing costs of the doors

[@BradAngove]

Indeed. Luckily they’re easy to veneer and machines can do much of the finishing these days.

[@devanbogan954]

I'm assuming you've experimented with the product in quarts at this time. have you tried rolling it on? since you're basically wanting a thick coat and sanding down anyways, in my opinion, you could probably roll it on to get a thicker coat of the non-rattle can without a spray gun.

[@BradAngove]

Yes, I gave it a try. It works ok, but as with most products that dry this fast, the roller tends to leave a fairly textured finish.

[@nitrousman8882]

great video! Thanks for sharing this. I have a speaker that is piano black with huge gouge in the surface.... almost like screws were put into it and the bottom was pulled free.... I'm filling with epoxy resin. Do you think that I need to prime first?

[@BradAngove]

Just seal it a bit first, even if it’s just with a thin coat of epoxy. Otherwise you can get air bubbles forming in the epoxy.

[@charlesbarry9194]

Good video! After the sealant is dry and sanded I noticed you didn’t use a primer, is primer not needed? Also I build stuff with mdf/wood together would I follow the same steps? T.I.A!

[@BradAngove]

The sealer fills the role that primer would generally be used for, so there’s no need for both. Yes; it works just as well on wood.

[@JW-mx3qg]

Just ordered 4 cans. What product do you recommend to keep a nice clear glossy finish ( using to seal a jobsite work table)

[@BradAngove]

Catalyzed polyurethane is probably your best bet. Or an enamel with a hardener.

[@jackloganbill605]

Great video. Any advice for signs made from MDF? It is a real pain to seal and sand the edges of each letter...face no problem, but getting inside and between the letters is a real pain...

[@BradAngove]

You may be able to get away with simply adding more of the sealer, but usually when I do those lettered signs I just have to spend a bit of extra time sanding those tough areas. The really tough areas are tough to see anyway, so you may not need to be quite as careful in those spots.

[@jessicajuneward7665]

I wish I’d watched this video before I did all my panelling.. any advice on MDF panelling that’s been painted in durable emulsion but I now need it wipeable and waterproof but not glossy?

[@BradAngove]

I don’t know what kind of material the durable emulsion is. Matte catalyzed polyurethane comes to mind though for a finish that meets those criteria.

[@jyrkiiinatti1660]

I use ordinary paintsealer. Works wonders on mdf. Very easy to use.

[@BradAngove]

I'm not sure what you mean by ordinary paint sealer.

[@valpanig]

@@BradAngove my mind is puzzled, where you get patience and sanity to answer every comment. Must be immaculate attention to details in trade

[@BradAngove]

I like answering people’s questions to help them out. Some of these other comments though... not so much.

[@HaulywoodReviews]

Thank you for posting this. I was trying to figure out how to seal MDF for a project I'm working on. Can you tell me why you turn the can upside down for a second when you are done spraying? I have never seen anyone do that, and it looks like you know what you are doing, so I thought I would ask. Thank you.

[@BradAngove]

Certainly. I made a video about it titled something along the lines of one tip that will make your spray cans perform better. There are a few types of nozzle for spray cans. These small ones, which are fairly common, only spray properly when they’re right-side-up. When you spray, paint can stay in the tube and jam it up. You flip it upside down and spray until material stops flowing (because it can’t pull material when upside down) and only gas is coming through to clear the nozzle so that it won’t jam up or spit.

[@HaulywoodReviews]

That's a great tip. Thank you for your reply.

[@BradAngove]

Your welcome. Thanks for watching.

[@gebrilsamuelbastiaan2280]

Hi, awesome video! explained in cleary and concise. Is this for all kinds of finish or just gloss finish?

[@BradAngove]

I would apply the same sealing technique for any finish.

[@Lloyd1885]

I wouldnt spend too much time sanding before the primer, any coating will raise the grain after. I coat the edges with shellac knotting or sanding sealer first, ir dries really quick to the particles in the mdf have less time to swell...oil based primer or undercoat is also good... I never use water based paints or primers on mdf, they are the worst for swelling the surface

[@BradAngove]

Mdf doesn’t have grain.

[@Lloyd1885]

@@BradAngove not grain n the sense of traditional solid wood no...but for want of a better term...fibres, swells the fibres?

[@BradAngove]

It certainly can swell the fibers.

[@Lloyd1885]

@@BradAngove using a water based, especially if it takes a long tíme to dry on mdf can leave it looking like woodchip paper 😔

[@anonymike8280]

I'm working on a computer desk with some water damage on the top. My experience is, ordinary wood stain seems to seal and stability the surface of MDF. The problem with MDF, I believe, is that the companies which make it do not know what the end user is going to do with it. So it end up being left to end user to further treat it according to their own purposes.

[@danielbal5272]

I think it is way better to use primer/sealer made for wood. With two coats I have never had a problem and our weather is humid all year.

[@BradAngove]

Vinyl sealer is made for wood. It’s called that because it’s vinyl based.

[@ronmartus]

I found the best solution to sealing MDF is Zinsser Cover Stain.

[@BradAngove]

That’s your top choice? I find that surprising, but I’m glad it works for you.

[@Jmyers0915]

Brad, awesome video. Is there a way to stain the MDF before glossing it? I tried staining last week and it didn't work out very well. Thanks.

[@BradAngove]

Mdf isn’t really meant to be stained. It doesn’t have grain. It also expands with moisture. I’ve sprayed alcohol based stain on it before and gotten an interesting effect though.

[@fishrrelaxing9361]

Cut your pieces long and run them through your route table with a straight bit. It will never be smoother. Then just top it with some 300 grit. Router bits work wonders on mdf.

[@BradAngove]

These were made entirely with a router. Routers do a smooth cut, but they do not seal anything.

[@mikegrit937]

should use the pigmented vinyl sealer since you did a solid color the pigmented has better filling properties

[@BradAngove]

+Mike Granata Does that come in the spray cans? I haven’t seen it in that format.

[@mikegrit937]

I,m pretty sure behlen has it, if not Mohawk finishing products has it in spray cans both companies subsidiaries of RPM inc.

[@bradleysmith681]

Thank you! Just what I needed..

[@BYGTraining]

Would this be a good way to stop the butt ends of a 2x4 from soaking up so much paint? I build slideboards and the bumpers are made from two feet long 2x4 segments.

[@BradAngove]

Yes, this would be helpful for that as well.

[@razie85]

watered down emulsion paint works well brush a few layers on then sand back ready for spraying

[@BradAngove]

That's an interesting idea. I've honestly never heard of using that before.

[@razie85]

Brad Angove a lot of people I know use emusion as a primer for interior gloss paint for mdf. I wondered if it will work for spray paint so i tried it the results were great . there isn't any visible defects that I can see and seems to be quite durable

[@BradAngove]

I'll have to look into that further. It definitely sounds like it's worth a try.

[@razie85]

I have only tried it with Matt emulsion. I don't think the others will work. also I hope you have a great new year

[@BradAngove]

Happy new year to you as well.

[@fotfoti]

Hi there, very nice video. I have a question tho about painting a furniture which consists of many different MDF parts. Lets say a bookcase. Which is the correct order? First assemble the furniture and then the whole primer-sanding-painting process ?or all pieces must be primer-sanded first , then assembled and then paint the whole thing? Thanks in advance :)

[@BradAngove]

+fotfoti It really is just a matter of preference. I like to paint the parts first so that I don't have to worry about causing runs by spraying into corners etc.

[@fotfoti]

thanks :)

[@BradAngove]

+fotfoti you're welcome.

[@adamrybka790]

Sorry but I disagree with previous reply. When you spray finish furniture you need spray dissembled otherwise you will have overspray on some places. Specially when you finish in high gloss.

[@peterotremba8980]

Thank you so much for making the video, you cleared a lot of stuff for me up but I have some questions. Can I use polyurethane over the paint and do I have to sand the paint a little before applying the poly? And does it matter if it is water based or oil based?

[@BradAngove]

Yes you can. Yes you should. No it doesn’t (once the mdf is sealed).

[@peterotremba8980]

Brad Angove Thanks

[@lyn1130]

Thanks for the video. I am actually trying to renew my old kitchen cabinet, do you think using your method in this video is appropriate for renewing the kitchen cabinet?

[@BradAngove]

As long as you’re not actually painting it in the kitchen you can use this to seal it. I’m assuming it’s MDF of course.

[@EPICSOUNDTRAX]

Hi Brad I am going to paint MDF room walls.I want to have flat or mate finish.The paint is water-based.Should I use some type of primer to seal the MDF or it will be fine?I do not want the MDF to swell.

[@BradAngove]

You should consider using a fast drying sealer to begin with.

[@organize1979]

Very useful video! Thank you! ....wanted to put a mask on you though!

[@DJAdelaar]

Hi, nice video! I work on a project where I wanna leave MDF with its original feel but still protects it from water and moisture. I don't wanna color it at the end. Is there any way to seal MDF so to say invisibly, that the feeling of raw MDF stays? Tnx for the answer!

[@BradAngove]

That’s an interesting concept. Honestly, I can’t thing of a way that you would do that. Any clear coat you put on it would smooth it out at least a little bit. The closest thing would be just putting a few coats of matte clear on it.

[@Marzen216]

Could I use Zinser Bin shellac based sealer underneath Duplicolor acrylic lacquer? A rattle can of vinyl sealer lacquer runs about $25 and the Zinser is only $10. I have two large mdf Marty subs to finish for my home theater and my kid is building one your guitar kits so I need a lot of coverage w/o breaking the bank. Thanks, we've gotten a lot out of your channel!

[@BradAngove]

It may take a couple extra coats, but yes that should work.

[@garymarrs2270]

Dynaglas body filler sand flat then rustoleum primer sealer. done

[@allisonspencer2021]

Has anyone ever laminated MDF board and then made a guitar body? If so I wonder how it would sound with say SD pickups etc

[@BradAngove]

Sounds just like anything else in that configuration with those pickups really.

[@rabwoody264]

Ok!! Now I know what they mean by saying "like watching paint dry "

[@BradAngove]

+rab woody luckily this paint dries quickly haha

[@saffadave]

how about a normal wood sealer the same as it you was going to varnish wood would this work with paint spay from a can

[@BradAngove]

It would work. It would just take a bit longer.

[@tayley284]

How moisture resistant would you say it becomes? I been looking for a definitave explination on how i can make standard mdf able to be used outside (undercover and wont get directly hit by any rain, but will have decent amount of moisture)... Someone please give me some tips👍👍

[@BradAngove]

You just need to seal it from all sides. The vinyl sealer is moisture resistant, and so are most clear coats. If you build up a gloss finish you should be good.