Finishing MDF

[Cutting Crew]

Hello all,

A happy new year to everyone.

I'm in the process of designing a new portable display stand for the coming year's exhibitions and fairs, I'd like to build it out MDF but I'm unsure of the finish I can expect to get.

The stand will be finished in a satin white, can anyone recommend a process bearing in mind the knocks it will get being moving about?

Ideally, I would like to spray the finish on in cellulose or some other quick drying material with undercoats to suit both the MDF and the top coat.

CC

 

[Gill]

Hi CC

Some people here have been able to achieve such spectacular finishes on MDF that I feel a little out of my depth in replying. However, I will .

If you don't prepare the material with an undercoat of some sort, the MDF will soak up the paint and you could end up with a blotchy, uneven finish. I've always achieved satisfactory results by sanding the piece, applying an MDF sealer, then cutting back very lightly with very fine sand paper before repeating the process. However, I've also used proprietary acrylic undercoats in the same way to good effect.

Once the piece has been prepared, I then spray paint it (assuming it's large enough - small pieces can be hand painted but the results are less consistent) with an aerosol. After waiting for the first coat to dry, I cut it back with very fine sandpaper and give a second coat. That normally does the trick for me.

Sometimes I don't use an aerosol, especially if the piece calls for several different colours. If it does, I tend to paint by hand using acrylic paints before coating the whole project with an aerosol car lacquer a couple of times! Those lacquers seem to give quite a nice satin finish.

I recently acquired a hobbyists air spray kit which I shall use to paint MDF next time. The only problem is that I can't get into the workshop right now because His Lordship is storing a 'bargain' bedroom suite there and won't bring himself to lug it upstairs :roll:.

Gill

 

[jasonB]

I tend to make a lot of stuff ftom MDF. Prefer to use MR MDF (Caber) as I find it less "fluffy". I then prime with Dulux quick drying primer/undercoat or Jewsons MDF primer. Then either a second coat of the primer/undercoat or dulux oil based undercoat. Finish with two coats dulux trade oil based eggshell. Smells a bit more than emulsion, touch dry in 3 hrs recoat same day if lucky, upto 12hrs in a cold workshop this time of year! Apply with 4" foam roller lay off with brush. Cut back with 320g silicon carbide paper between all coats.

I have also had good results on small items with Plasticote spray cans, primer then topcoat, rubbed down as before then a couple of coats of Barfords Aquacote for extra durability.

Some people go for emulsion , I only use it on joinery when doing a distressed finish and tend to seal with either acrylic matt varnish or the Aquacote in higher wear situations.

If the doors mave raised MDF panels then I seal these with celulose sanding sealer and rub down before making up the doors.

Jason

 

[Philly]

A mate of mine has done his bathroom out with built-in units from MDF-he sprayed them with Smoothrite white gloss (you know, smooth Hammerite)
They look fantastic-well worth a try.
Hope this is of help
Philly

 

[tim]

I do pretty much what Jason does but if edges are not lipped I find sealing them with thickish wall paper paste to be really effective (and very cheap). You can easily get a great finsih with MDF, you just have to be prepared to give everything at least one extra coat of paint. Given that most things made in MDF are flat panels using a spray gun , roller or wide brush makes pretty quick work of that.

T