Best paint for airless sprayer onto MDF

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Neocleous

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Hi everyone,

I’ve just bought a Wagner 150M airless sprayer to paint some bedside cabinets that I have built out of MDF but I need some paint advice.

What’s the best brand to use if there is one? I would like a mat finish and a mat clear coat to protect the paint finish.

I have some Zinsser bulls eye 123 that Can be sprayed as a primer and I’ve always had good results when using a brush or a roller but does this spray well?

Thanks for the advice
 
I'd say you'd probably be better off spraying with a HVLP turbine with water based paints watered down a tad (upto 25% iirc). Airless sprayers are a bit more for interior\exterior surfaces - to my mind. I have both and that's what I've used mine for. YMMV tho.
 
I got the airless because it seemed a bit more flexible and has a wider range of paints that can be sprayed.

I’m just not sure which paint works best, from what I’ve read even with an airless sprayer the paint still needs to be thinned a bit.
 
I use a Graco Ultra (airless cordless handheld machine) with Morrells water based lacquers for all my projects.

It is a bit of a beast in that it throws out a lot of paint very quickly, however with a bit of practice it covers large areas (full sheets) very fast and the finish with the Morrells WBL is fantastic.

Overspray can be a problem in the higher settings but as with all spraying only use enough power to atomise the paint, any more is a waste and will just result in bounce back and a coating of overspray fall out on everything in the vicinity. If you use the right setting overspray is next to nothing.

In my machine I use the smaller of two supplied tips (green 314 FF tip) and don't thin either the primer or top coat material at all, just strain it with a 180micron paint filter straight out of the tin. You wouldn't be able to do this with a HVLP setup, they however can usually spray anything, I am limited to WB materials only, no BIN or OB paints. I don't know the Wagner machine you mentioned but I would check that oil and meths based paints are safe to use in it.

My usual painting procedure if you are interested is;
  • use MRMDF, don't bother with "standard" MDF, you'll save yourself hours of work for the little extra cost!
    fill any obvious holes, gaps with 2k or 1k filler (not caulk!!)
    sand all faces to 240 and edges up to 320
    spray Morrells 501 primer, really light quick mist coat first then a heavier one once the first is touch dry (this stops a lot of the fiber raising you get with MDF and WB paints)
    drying time varies with temp/humidity but can be as little as 20mins until you can sand
    fill any remaining imperfections (the primer makes them more visible so easier to find)
    flat back with 240 on faces, 320 on edges. Don't sand through your primer or you'll have to spot prime those areas, be careful with the corners.
    two top coats of the Morrells "italian WBL" this can be mixed to any colour and sheen level, I usually go for 30% sheen which is about equivalent to an eggshell.
    key between top coats with 320 everywhere.
    I do the edges from both sides of the board so they actually end up with two primer and four top coats (two from each side).
    top coat material has a similar drying time but more importantly as it a lacquer it can be stacked the next day without the parts sticking together. Acrylics (think Valspar V700 etc) can't be stacked until they are full cured which can take several days if not weeks.

Obviously the usual painting rules apply, clean machine, strain the paint (even brand new unopened tins), vacuum everything including the floor/spraying table before starting and wear the relevant PPE (half face mask with P3 filters and extraction of the room/workshop if possible)

Clean up is done in the kitchen sink with warm water out of the tap and running it through the machine until everything is properly clean.

The best way to learn is just to do it and experiment.
Don't worry if you b*gg*r it up, it's easy to fix, just sand it back and have another go.
If you want any more help just PM me your number and I can give you a call.

Good luck and happy spraying! Once you start you'll never touch a brush again!
 
Will1983, a concise and helpful writeup!

Can I ask, do you sand by hand or machine or both? Esp the 320 keying between coats?

Sent from my SM-G973F using Tapatalk
 
No worries Sammy, glad to help.

I usually do all the sanding with the RO sander on the faces.
There isn't really a good way to do the edges with the machine without rounding them over so they are done by hand or very carefully on a low speed with the RO.

Obviously some areas you can't get the machine in so they have to be done by hand on a block. Don't be tempted to skip the block, if you just use your fingers you will just make the surface wavy. The block bridges the lows and therefore takes more material from the highs bringing them down so everything ends up smooth. This is even more necessary for high gloss finishes where the slightest imperfection in the surface will be more evident.

I always have some sort of vacuum extraction going whilst sanding, it helps to stop the Abranet from clogging and removes the dust so you can easily see where you are up to. Good lighting (LEDs) shone on the surface at a raking angle really helps to.
 
Thanks Will that was really helpful.

The sprayer arrived today but I haven’t had a chance to try it yet. I was going to try the Tikkurila paint that Peter Millard mentions in his video but it doesn’t seem readily available in my area.

The cabinets I have built have been made out of Medite MR MDF so hopefully they take the paint well.

I saw a video on YouTube where a professional bespoke furniture company (the name escapes me at the moment) recommended putting a coat of Zinnser 123 on the edges and priming on top of that. Do you think there would be any benefit in that?

Thanks
 
There are as many ways to go about painting edges of MDF as there are ways to sharpen a chisel.

I've tried most of them in the past few years (incl using BIN) and IME it is easiest and fastest just to sand them to 240 (320 if you can be bothered), paint them with a decent primer and then flat it back after each coat.
The real key is to use proper MRMDF in the first place, the non MR stuff just makes more work for you. Whatever you do though there isn't any way to get out of sanding between coats.

RE Tikk, I've not used it for the same reason as you, not easy to get hold of. Give Morrell's a ring, they deliver next day for free and I've been very impressed with their customer service to date. Not an advert, I'm just a satisfied customer.
 
I spoke to a rep at Morrells who recommended the 490 primer which is a low viscosity variant of the 520 primer. He thinks that will spray better with my machine and is also water based. I didn’t fancy spraying solvent based paint at home.

He also recommended using their 450 series top coat. Though I would share as it may benefit someone else.
 
Most of the important stuff has been covered by Wills 1963..well done Sir.

I would add that MRMDF is not all the same. I use only Medite MR-MDF as I have found other brands to be a bit fluffy at times.

I also use HD_MDF which is a heavy duty more dense version of MDF but is harder to find and has the disadvantage of being a little heavier.
 
Beech 1948 is absolutely right about not all MRMDF being made equal, for example the junk they sell in wickes is no better than normal MDF.

I'm not sure who makes the stuff I use, I get it from my local independent timber merchants, but it is great stuff. Been doing a load of edge sanding with 240 on the RO this weekend actually! I considered taking some photos of the process but just to busy at the moment.

The 450 series is the material i use for top coats, lovely stuff but you will probably have to thin it for use in a HVLP machine. Just don't forget to strain it!!!
 
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