Tips for painting cabinet doors (MDF)

[nospambob]

[Yves]

Hi,

I need some advice for paintinf mdf doors (Spray).

I used to spray lacquer with sealer over wood.

But If I want some other color on MDF, what product is best.

I don't know what type of product gives the best finish, or on what type of paint can I put laquer on , or should I use lacquer at all.

Thanks.

[John]

Good interior grade latex will work great

John

[Jay Pique]

I've heard great things about products from Homestead, but have never used them. I have used the Magnalac series from M.L. Campbell

quite a bit. The antiqued yellow look is apparently "hot" these days, so we've been using quite a bit of the MagnaMax White/Opaque Base that's been pigmented to match the customer's color preference. Prior to this, however, we use Magnalac Primer/Undercoater as the base coat.

A few things I've recently learned - I'm posting them here for those who may be in the position I was about 2 months ago!

- Sand well, especially on any freshly exposed MDF areas. We only sand the hardwood frames (usually poplar) to 120, but we take the MDF to 220. Any tiny knotholes, cracks, dips or gaps in the joints will show up much more clearly with paint than they will with clearcoat. You can putty after the primer (as well as after a coat of the lacquer itself), but it's more efficient to try and do it all at once,and proprly,the first go-round.

- When applying the primer, you needn't go real heavy when you band the edges, as they'll get hit again when you do the other side. Plus, since they are vertical surfaces they are more prone to drip. I take a quick pass on all four edges and then lay on a thick coat across the surface.

- After banding, I align the door so the long edge points into the spray booth. It seems to make it easier for me to get even overlaps, and thus even coverage. Then I stand just off the back right corner of the door (I'm a lefty), angle the gun 10 to 15 degrees into the booth and start on the nearest corner, moving the gun back and forth across the board. Paint is much easier to see from a coverage perspective, but still can present problems with bubbling, dry spray and overspray. I *think* I hold the gun a little closer to the work and move a little quicker back and forth. The first one or two passes should cover the nearest rail/stile and now you're on to the junction of the panel and the frame. This is where it gets just a little tricky (for me). I've learned to sort of roll my wrist under a little bit to get the spray to hit the inside edge of the board you just sprayed. It's just for one pass, but it can really make a difference. From there on out it's just a back and forth motion with a little wrist action so the inside edges of the frame get touched with finish. I go pretty heavy.

- After priming the first side, we only let it dry for an hour or so before flipping them to do the front. When doing a full kitchen there's no delay at all. After everything's primed, we let it sit overnight before sanding.

- The next day you'll want to get your sanding station really well equipped. I cut up a bunch of 220 squares for the quarter sheet sander and for hand sanding, grab a can of putty and a couple different knives, hook up an airhose with a blower nozzle (VERY important) and get the whole stack of them set up right where I can grab them. Since you didn't have any drips or runs, you won't need any scrapers or pads in the vise....

- First off, I grab a door and check to see what needs puttying. If it needs it, I make sure to cut away enough finish so it will stay seated, and then I take pains to not glop it on there. A quick pass with the putty knife should leave a nice smooth, slightly elevated surface. Don't mess too much with it or it'll dry out enough to get grainy and pull away. If it needed puttying, I set it aside at the end of the line. If not...

- Then I whack both sides with the quarter sheet sander, and quickly blow it off to remove the swarf. If you don't, it's likely to clump up and reattach itself to the door. Since you'll be blowing dust all day (you'll look like a drywaller) you definitely want to wear a good mask. Better yet, have a dedicated sanding station equipped with dust collection. We don't have one, so I put away the DustBeeGone and break out the Dustfoe 88. It just feels like it's providing more protection.

- Next I pass over the edges. making sure to knock down the little burr of finish that's frequently there. Don't worry too much about going through the primer, because the pigmented lacquer will cover it.

- Next up, I hand sand the profiles. I play around with folding the sandpaper this way and that for a while, and then settle on "the best" method - and then repeat it for each and every door. It makes it easier for me to be sure I've hit all of the surface and provides a level of consistency about which I'm a bit anal.

- Lastly, I blow off the door and then work surface. I give the door a final runover with my hands to feel for rough spots, and then set it in the "done" stack. Next door.

I'm sure I've forgotten some things, but that's the gist of it for me.

JP

**************** You'll need a sharp chisel to clean up the miters too.

[nospambob]

Would it be possible to put a fan behind you to blow the sanding dust into the spray booth? I have a fan in the window and another behind me when spraying and have no overspray problems I'm aware of.

want to wear a good

We don't have one, so I put away the DustBeeGone and break out the Dustfoe 88. It just feels like it's providing more protection.

[Jay Pique]

Absolutely. We've got a pretty big booth that wouldn't even require the fan behind you.

JP

want to wear a good

We don't have one, so I put away the DustBeeGone and break out the Dustfoe 88. It just feels like it's providing more protection.

[WoodChuck34]

I just finished painting 8 raised panel doors (2 panels/door). FWW just did an article on painting MDF an issue or 2 ago. They recommended smearing drywall compound on all cut edges and sanding smooth. After that, apply a shellac or oil based primer. Final coat can be anything you want, including latex. I must say, I wasn't excited about the extra step (drywall compound), but it certainly made a big difference.

Chuck

[Rich Dell]

What do you guys think about using popular for rails and stiles, and MDF for panels? I like the drywall compound idea for the simpler panel edges, but not the more intricate rail and stile details.

Thanks, Rich

[Pat Barber]

[bridger]

in the FWW article (I was just looking at that the other day...) they suggested using the same router bit (handheld) that cut the detail as a cleanup tool for the drywall mud. you definitely do want to seal the cut edges of the MDF with something. shellac would probably do fine for that, though it won't have the same filler abilities.

poplar frames and MDF panels should be fine.

[Jay Pique]

I'll bet it did. Even sanded to 220 like we do, it still looks pretty bad IMO. I'm going to suggest it to the man. We'll see....

JP

****************** Meliora.

[B a r r y]

Poplar is easy to dent. I'd stick with MDF if I wanted cheap, or use birch or maple for durability.

Barry

[rj]

I used a "soupy" mix of patching plaster and painted it on the MDF, then sanded and painted. Poplar worked fine for kitchen cabinet rails/stiles/& dace frames Ray

[bridger]

mdf is a terrible choice for rail and stile components. use wood for that. mdf will be fine for the panels.

[B a r r y]

With the proper hardware and assembly, MDF can be fine for rail and stile. With an all MDF door, the panel can be completely glued into the grooves, making the whole assembly quite durable. One does need different screws for the hinges.

MDF would stink for rail and stile, if you attempted to keep the panel floating.

Several years ago, I made some rail and stile MDF doors for a nursery school, they're still holding up great.

Barry

[WoodChuck34]

Rich,

I actually did those 8 panel doors in a basement playroom I'm finishing. Its been my own personal labratory. I did 6 of those 8 panel doors using MDF for the rails and stiles. I was curious to see how it would work and the lack of warping issues was also attractive. They want together fine and I did glue the panels into the rails/stiles, but the back edge of the groove on the rails/stiles is very weak. The weakness isn't an issue after gluing the panels in, but if the rails/stile don't fit together just so, the back edge of that groove will just pop off.

I read the FWW article in between doors 6 and 7, so I did switch to poplar. Worked fine.

I actually had the doors with the MDF rails/stiles finished but not painted before reading the article, so I did go back and use the drywall compound after the fact. Because of that, I was unable to scrap the excess compound off with router bits. I just rough sanded them with drywall compound sand paper (the stuff that looks like screening) and then finish sanded with 220 grit. The thing about drywall compound is that its easy to sand.

Chuck

[bridger]

if you're gonna do that why not just mill it from a sheet?

[Tom Watson]

Good idea, Bridge - can I come over and borrow your CNC this weekend?

Regards, Tom.

Thomas J.Watson - Cabinetmaker (ret.) tjwatson1ATcomcastDOTnet (real email)

[B a r r y]

Milled sheets have rounded corners in the "panel", like the "Thermofoil" doors sold in BORGs.

Rail & stile glued to a panel, can look just like a "real" door. Since the panel dosen't need to float, the whole assembly actually ends up quite strong. This is important if trying to match an existing style, and they look more like higher end doors at trailer park prices.

If I'm painting doors, I prefer maple or birch, but some folks have really tight budgets.

Barry

[Tom Watson]

Ain't necessarily so. See below (there are many others).

The square cornered versions cost a little more.

Regards, Tom.

Thomas J.Watson - Cabinetmaker (ret.) tjwatson1ATcomcastDOTnet (real email)