Main > Main Forum

Spray Painting MDF

Pages: << < (2/9) > >>

sealslayer:

You can still achieve a perfect finish with spray cans but your going to need a lot of them, so many so that it may be worth your while hiring a compressor and spray gun for the weekend.
You may also encounter problems with overspray using cans because your not going to be able to spray a large area quick enough unless you have a couple of helpers shaking the next couple of cans ready for you to use, you can buy triggers that clip onto the top of the cans to make life easier on your thumb.
Car spray paint is touch dry pretty quick so you may be better off spraying one section and masking the other areas off to avoid overspray then let the panel you've sprayed dry then cover that one and continue with the others etc...

I used two different grades of farleca compound, I'm not sure what country's its available in but a good car spray paint shop will sell rubbing compound, make sure its a shop dedicated to car paint and not a general car spares shop as they will only sell regular cutting compound that ends up taking too much paint off.

Start with ultra fine wet n dry paper 1200 grade or higher with warm soapy water, washing up liquid is best. first to get rid of any orange peel effect, only lightly sanding otherwise you'll take too much paint off.
when you have it nice and smooth and it all looks a uniform matt texture with no shiny pits in it use the first regular grade of compound on soft cloth wet cloth in circular motions until the shine starts to appear, wipe that off then use the ultra fine finishing compound for the last stage, then use a nice car wax to get the gleam  :applaud:

Make sure you have left the paint to dry long enough, two weeks is best unless you can leave the cabinet in a room with the heating on for a week so it gets time to bake nice and hard.

Fozzy The Bear:


--- Quote from: leapinlew on November 11, 2006, 02:37:42 pm ---I'm building a bartop and I wonder what peoples thoughts are on using spray paint on MDF?

Does it go on even? Does the finish hold? Do I need to prime it first?

--- End quote ---

Spray painting MDF is really easy..... I know exactly why people have problems with it, and the cure is so simple that it seems to have been missed here.

The problem with MDF is that it soaks up paint like a sponge and dries rough as hell! Unless you follow this little tip:

1) Sand thouroughly with 400 Grit wet and dry paper, used DRY!! very important don't get the MDF wet YET!!

2) Get some weatherproof PVA (White Glue) and thin it down approx 30% PVA to 70% water... maybe even a little thiner than that.

3) Paint it on with a brush! letting it soak well into the the MDF.  Give it pleanty of time to dry out.

4) Your MDF is now sealed and you can sand the surface with 600 Grit Wet and Dry Paper (again used dry)

5) Spray paint the surface with any finishing paint you like ( I like Plasticote "Rust Not" Matt Black, for black finishes... It comes kind of satin finish on this surface) The finish will look almost exactly like it's been laminated.

No need for primers and huge numbers of rubbing down layers and all of that stuff!! Just whak the top coat on. It holds really well on top of the PVA sealer and looks great!!

Best Regards,
Julian (Fozzy The Bear) 

AlanS17:

I just started pealing the sideart from my TMNT cabinet, and it looks sealed underneath. Would this be safe to paint on? I'm assuming so. Could I get away with using a roller or do i still need to spray?

johnvv:


--- Quote ---The problem with MDF is that it soaks up paint like a sponge and dries rough as hell! Unless you follow this little tip:

1) Sand thouroughly with 400 Grit wet and dry paper, used DRY!! very important don't get the MDF wet YET!!
--- End quote ---

I'll disagree with Fozzy, though his method may well work.

- If you are going to sand MDF, you must use a mask and work in a well ventilated area.  The MDF dust is, esentially, toxic.  Check prior threads on this.

- The point of priming MDF is to a) protect it from water and moister which will severely damage MDF and b) give it a smoother surface for the paint.  There a lots of threads on this as well.

So, it is not really much effort to spray (with a can) or apply (with a roller) one or two coats of primer.  You just need to lightly sand, by hand, between coats.  Wont' take more than about 5 minutes per side to sand.  If you use an oil-based paint then you must use an oil-based primer.  for latex paint, use a water-based primer.

As noted earlier, regardless of which method you use, let the paint cure for 10-14 days before doing any further work on it (polishing, side art, etc).



Fozzy The Bear:


--- Quote from: johnvv on November 12, 2006, 02:45:47 pm --- The point of priming MDF is to a) protect it from water and moister which will severely damage MDF and b) give it a smoother surface for the paint.
--- End quote ---

Sorry?? You're not disagreeing with me at all.... That's exactly what I said.

However: The method I gave there takes 1/10th of the time because you don't have to wait days for two primer coats to dry with sanding in between and it takes the topcoat straight onto the sealed surface with near perfect results.  I've never had it fail on me yet. On top of that you can paint it with water based or oil based paints with no adverse reaction.

The PVA soaked into the MDF seals and protects it totally, preventing moisture penetration of any sort. In fact so much so that I've seen and been in a boat built this way.

Try it out for yourself! It works, it's faster, it's cheaper and it requires 10 times less effort to get a great result.

As for letting the paint cure for 10-14 days before doing any further work on it (polishing, side art, etc)..... If you follow the above method and use the paint that I suggested you can do all of that after 10 hours! after that amount of time it's rock hard set and more or less cured.


Best Regards,
Julian (Fozzy The Bear)

Pages: << < (2/9) > >>

Go to full version