How to get smooth painted finish on MDF?

[gychang]

I have been advised to use the oil-based primer but forgot to ask how to get a smooth painted finish.

1. Do I have to buy a separate spray paint gun? (or rent).
2. Does the spray can work (brand) ? (I am building a small speaker)-will assume the brush will leave marks.

thanks,

gychang

[Bulkley]

Spray will give a smoother finish than brush. If you don't have spray equipment, you can get away with spray cans on a small job. The trick is to take time. Do lots of very fine coats and build up layers. Resist the urge to do it quickly. Allow each coat to dry.

Yes, I would use a primer.

I have an HVLP turbine sprayer. I use an alkyd primer with an acryllic top coat. It works well on MDF.

[LCHIEN]

Is Kilz a good primer for MDF?
It doesn't say on the can whether its a water-base or oil base but the clean-up instructions say mineral spirits or paint thinner so I'm guessing its oil-based.

P.S. OK, I'm pretty dense today. I read the fine print on the back but neglected to read the front, in big red letters it says "Interior Oil based"

[Bulkley]

I have only used Kilz on window sills, applied with a brush. I don't know how it sprays.

[downtheroad]

I have been advised to use the oil-based primer but forgot to ask how to get a smooth painted finish.

1. Do I have to buy a separate spray paint gun? (or rent).
2. Does the spray can work (brand) ? (I am building a small speaker)-will assume the brush will leave marks.

thanks,

gychang

I also live in Orange County and work with a finisher. We use water-based products almost exclusively and have been using Enduro Wat-R-Base polyurethane coatings (available at Austin Hardwoods in Santa Ana). Enduro 's water-base primers/sanding sealers are fantastic and sand very well. We've finished a lot of woodwork with Enduro clear and colored coatings using an HVLP spraygun, which is the best method to apply a smooth coat.

If you have a need to have a custom color made you can contact General Finishes.
(262)642-4545
www.generalfinishes.com

[downtheroad]

I forgot to mention that Enduro was made by Compliant Spray Systems of San Clemente, CA and was recently acquired by General Finishes at the end of last year (2006). Although we use to get custom colors made by Compliant Spray Systems, General Finishes is still offering this service in minimum one gallons.

[jlm]

Another good way to get a smooth paint finish on MDF is to use a small foam roller. The finish won't be quite as smooth as if you sprayed it, but it won't show brush marks or roller marks if you're careful and use several light coats (possibly with light sanding or steel wool in between coats) if you get dust nibs or air bubbles. Adding a flow-out additive like Floetrol to the paint will help a lot, too.

I built a small MDF cabinet for the bathroom and painted it this way, and the finish looks very similar to a spray job. I used KILZ oil-based primer (the red and white can - the blue KILZ is latex), then three light coats of semi-gloss latex (with Floetrol added) using a four-inch foam roller, and it came out great. Since you're painting the outside of a speaker box, you have no inside corners to worry about (that's where a sprayer really shines), so you should be able to get good results with a roller. Just be careful around the edges, if you push down too hard on a roller, it can drip around the corner. Use a light touch, and you might be surprised how smooth you can get it.

If you want to spray it, KILZ is available in spray cans. Same advice applies - use several very light coats. If you think it's too light, then it's probably about right.

[siliconbauhaus]

I didnt have much luck with the foam roller....I guess I was pressing too hard as I kept having the paint go over the edge.

[thestinker]

I've tried foam rollers with no succes. Looks like a retarded monkey painted.

[jlm]

The technique I've had success with is to start painting from the center of the panel or side, and work outward to within an inch or so from the edge. Then just work paint that's already on the surface out carefully to the edges, so your roller isn't holding much paint when you get to the edge, so you're less likely to squeeze out drips. It's definitely not like painting a wall with a roller, where you're just looking for quick coverage. It takes a few light coats. And I can't recommend Floetrol enough - it really helps to "level out" the paint.

But I'll admit it took me a few tries to get the technique right. I practiced on scrap MDF because I didn't want to ruin the cabinet (and at the time, didn't want to buy a sprayer).

[steve-norrell]

I can't recommend Floetrol enough - it really helps to "level out" the paint.

Jim and others,

Do you use Floetrol in the paint, or primer, or both?

Thanks, Steve

[ivwshane]

I painted some baseboards and the smoothest finish I got was from using a foam brush (NOT A FOAM ROLLER). It took a couple of coats because it goes on quite thin but it was smooth none the less.

[gychang]

The technique I've had success with is to start painting from the center of the panel or side, and work outward to within an inch or so from the edge. Then just work paint that's already on the surface out carefully to the edges, so your roller isn't holding much paint when you get to the edge, so you're less likely to squeeze out drips. It's definitely not like painting a wall with a roller, where you're just looking for quick coverage. It takes a few light coats. And I can't recommend Floetrol enough - it really helps to "level out" the paint.

I will have to try this, thanks for putting up your experience. Is the Floetrol available at HomeDepot?

thanks,

gychang

[gychang]

I painted some baseboards and the smoothest finish I got was from using a foam brush (NOT A FOAM ROLLER). It took a couple of coats because it goes on quite thin but it was smooth none the less.

this sounds like ?easier than roller?

thanks,

gychang

[bigangelman]

smooth finish

Floetrol is for latex paints, penetrol is for oil based paints (great product).
I opt for oil base over latex, it dries slower give you more time to work with it and holds on better. You only get once chance at the first coat so do it good. Foam roller then brush it out to lay it off. The roller is to get the paint to the surface and even it out, then lay it off with a brush. I'd use a regular oil base primer not a fast drying one like Kilz. You can also use a 1/4" nap roller, but remember to defuzz the roller before use, easiest way is to wrap the cover in masking tape then remove. Sand between coats & dust off.

Tom