Any decorating experts know the best prep and paint procedure to get a nice matt white finish on some big doors and drawer fronts? On the one hand google says it’s easy because MDF is so smooth but then the next hit says it’s difficult because MDF is so absorbent!

Both are true. It takes paint well and is pretty much easy to get a good finish but you can end up using a lot of paint. Either use a proper undercoat or do a first coat with a bit of water. The edges can really suck up paint

Decent undercoat and paint, sand between coats, usual stuff

Yes you might need several coats especially on the edges. Undercoat, dry, sand, paint, dry, sand and keep doing it. I even used wet & dry on our MDF cupboards.

Makes sense! So onto specifics, what is a decent undercoat? And what’s a good topcoat? I hate buying paint there’s so much choice and such a wide range in prices. The wardrobes cost like a million pounds so I’m not looking to skimp on the last bit!

I’ve found using a mdf primer (it’s a bit like a weak pva glue mix) then a traditional undercoat (couple of coats of each) make applying the actual wood colour paint much more pleasurable. Of course if you have spraying facilities it’s far easier but should get good results with a small roller and brush

I have used zinsser bin, which is shellac based and doesn’t raise the grain
Also a green foam roller gives a very acceptable finish
Good luck

MDF primer for raw or heavily sanded MDF, then undercoat. I am currently working my way around our house as every room, every door frame and every sill in entire house has just been replaced. It is never ending, tedious and expensive job, Easy to mess up and guaranteed to cause arguments with Mrs.

MDF is nice and stable but a pain in other ways.

Around the edges and drilling’s for fittings 50:50 water:paint then when dry 25:75 water:paint, Let dry then do your undercoat etc.

This was recommended to me by a decorator and worked well when painting a MDF door white.

MDF is nice and stable but a pain in other ways.

…. until you paint one side but not the other:-)

because it’s quite absorbent make sure your sealing / painting the backs of panels in roughly the same way as the front otherwise the back will absorb moisture, the front won’t and you’ll have nice dish-shaped doors.

There are a couple of YouTube carpenters who work with MDF and get good results. Peter Millard is worth checking out and this bod, Gosforth Handyman did a thing on it here

Or use moisture resistant MDF. Comes in a variety of grades

I used zinnser 123+ primer then white eggshell. Took a long time with brush + rollers.

Depending on the finish you want I’ve had success with car primer rattle cans and some cans of plasti kote textured spray paint… Left a kind of powder coated finish seems hard wearing.

I’ve used this stuff quite a bit when making mdf wardrobes etc.

It’s quite good. It’s kind of a bit thicker so seals the edges well. Still want two coats though.

I also used to give the edges only a few coats of water based varnish, flat it back. Comes up beautifully. Then prime and paint.

As with others a pre made mdf primer is best. Sure you can mix pva and water and paint that on, but its one of those q1uick fixes and never seems to sand as well as it might. In that I dont think it penetrates enough and by the time its smooth, you’re through in places. The pre made will have penetration and drying added.

MDF primer is suitable for the entire board, all faces, the main flat faces are already smooth, its just any machined parts or the edges that might need a couple of coats, sanding to 240 grit inbetween, yes damn those edges.

If you dont sand and seal, and sand again the edges or machined bits take on a fluffy appearance when a finish is applied, oil, paint etc.

MDF is under appreciated as a medium for making furniture or internal joinery. Many start off bias, considering it a less worthy material, but in use and with ingenuity, its great stuff, but the dust isnt, and tends to be able to render itself down to sub micron size no matter how you cut it so a dust mask is a given.

Its a nightmare.

I heat gunned the foils off my entire kitchen so it was raw MDF.

Took ages and ages and the finish isn’t great.

Dulux paint mixed to order from a decorating supplies place was so much better finish than the crown from the same place.

@Wzzzzz
Might find the residue adhesive from the foils has penetrated the surface. Did you wipe it with meths or anything like that

My wife has just painted some furniture with some of this stuff

https://frenchicpaint.co.uk/

Done drawer fronts, back of a door and a recessed chimney breast wall. Goes on easy, covers everything nicely, no prep or primer needed.

I’ve not looked if there’s one specifically for your needs, but probably worth a look.

I make and paint quite a lot of MDF furniture. The Leyland MDF primer is decent, but I get just as good results using their bog standard acrylic primer undercoat which also happens to be less expensive. I tend to sand faces and edges to 240 grit, get a coat of primer on to ‘raise the grain’ (I’m aware MDF doesn’t have a grain in the traditional sense but you know what I mean), then sand again at 240 or 320 before using Leyland hard-wearing acrylic eggshell. Two coats of this using a Rota double concave foam roller gives a good finish, which I’ve never had a complaint about. I do use moisture resistant MDF, but the same principles apply to normal MDF you just may need to repeat the sanding/coating process more times.

Acrylic undercoat 1st coat, good rub down then another coat of accy followed by whatever paint you choose, the endgrain takes some paint but comes up alright after a rubdown. I’m a decoarot and thats how I’ve always done it. Mini roller saves some time!

I find a light skim of wood filler along the edge helps stop the paint absorbing too much.

Well, by coincidence, Peter Millard has done a video this week on just this.

Basically what Mat8246 said.

Essentially as others have said undercoat and primer is key. Unless it’s waterproof MDF then it reacts badly with water, so I always seal with solvent based primer rather than a water based primer. Once sealed it’s a question of, like any paint work, of building up a good flat base on which to put the top coats on. Essentially rubbing down between each layer but being careful not to sand through sealing layer

Unless it’s waterproof MDF then it reacts badly with water, so I always seal with solvent based primer rather than a water based primer.

I always do the edges with water based varnish. Works really well. I do mostly use moisture resistant mdf mind.

Im actually desperate to get some of this Valchromat MDF, or HDF i believe it actually is(High density fiberboard).
Available in different thicknesses down to 8mm But it is available in a huge range of colours and could be applied directly over existing woodwork/panels

Yeah Valchromat is cool. Expensive though. Very dense and quite different from mdf.

I built a load of shelves for a yoga studio in Birmingham a year or so back. Came out every day looking like a coal miner 😂

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Finished off a week of work today building and installing these awesome cabinets for and designed by @mjmbespoke for a new yoga studio and fitness mecca in central Birmingham, @anarchy45uk All built in stealthy black @valchromat I made sure to align the shelves as well as my Chakras… #wood #woodworking #woodworkersofinstagram #valchromat #valchromatfurniture #mdf #stealth #black #yoga #yogastudio #birmingham #shelving #shelves

A post shared by black tea one sugar (@blackteaonesugar) on Oct 12, 2018 at 11:38am PDT

I’ve done a couple of pieces from a combination of black Valchromat and oak (combination of solid oak and oak veneer).
It looked great before I put any finish on it, the Valchromat looked great after I’d put one coat of Osmo PolyX satin on but the oak needed another coat. But when I put the second coat on, the oak looked great but the valchromat looked worse. I’m stumped. Do I sand the whole lot down, mask off the Valchromat and put a coat on the oak then remove the Frog tape and give the whole lot a coat, or is it just my technique?