Painting MDF cabinet doors

[Ole Anderson]

Gotten myself into a fine mess. I agreed to make up nearly 40 cabinet doors for my church kitchen project using 3/4" MDF with a routed ogee edge. Six 4x8 sheets of material. I googled "how to paint MDF". Nobody agrees on the best way to seal the faces and edges. Ten years ago I did a few for my son and I sealed the edges with thinned wood glue. Turned out ok, I might have sealed the faces with shellac. This time looking to spray the finish coat with my airless X5 using a cabinet grade satin latex acrylic from Behr or SW. Painting will be done in my garage heated with a ceiling mounted vented gas unit heater. Yes I am in Michigan and it will be a February project. Some recommend a lacquer sanding sealer, brushed on, others a shellac sealer, others automotive primer and so on. Not looking to get crazy with exotic materials like conversion varnishes and the like, just stuff available from the big box stores or SW. Worried about spraying lacquer or shellac due to it being volatile. I will use an automotive grade 3M paint respirator regardless of material. What say you?

[Jim Becker]

I sand the edges as fine as I can and use spackle/joint compound to fill and seal edges. Sealing with wax free shellac can also help. In both cases, light sanding is required before moving to primer...and. high solids primer isn't a horrible idea to help with the cut edges, too.

[Allan Dozier]

When I have a small MDF project I just grab a rattle can of spray shellac. With 40 doors I would probably spray with shellac based primer.

[John TenEyck]

Ask SW's about a high solids primer for MDF. With that many doors I'd want something I could spray.

John

[Ole Anderson]

I stopped at SW and asked about priming MDF. The counter guy recommended their Extreme Bond Primer. Not sure why as bonding isn't the issue filling pores is. Kilz Premium 3 vinyl seems to get good recommendations for use over MDF at half the price. I'm leaning toward using this. Only issue is that it isn't intended to sand well. But with one coat by airless I should be good for two coats of final Satin Marquee, lightly sanded 220 after the first coat.

[Jim Becker]

The extreme bond primer is good stuff, but I'm also perplexed at the recommendation of the most expensive, premium product for the issue that you were describing to the person at SW. Extreme bond is great when there are actual bonding challenges...such as slick oil based paint to be covered with new paint and other situations. I don't believe it has more solids in it, however, but I could be wrong about that. I think I'd want a product that has those solids and is also very sandable so that the first coat fills, gets sanded back and then a second coat completes the sealing. (one or more additional iterations might be needed, depending on the actual cut surface being prepped)

[Tom M King]

I don't think I would use a vinyl. I've never liked the way any vinyl primer sands. Shellac based primer sands easily, and is what I've always used. A couple of coats since the first one will mostly soak in. I spray it outside really thinned down for the first coat. I keep a cheap single stage HVLP just for that use.

Some of the newer water based primers should work fine too, but I've not used one yet for MDF edges, so can offer no advice. If you're going to spray inside, this would be a better option. It does sand nicely.

[John TenEyck]

This SW's product is made for MDF:

https://industrial.sherwin-williams....r.9808637.html

John

[Curt Harms]

I sand the edges as fine as I can and use spackle/joint compound to fill and seal edges. Sealing with wax free shellac can also help. In both cases, light sanding is required before moving to primer...and. high solids primer isn't a horrible idea to help with the cut edges, too.

That's what I've used in the past, light weight fast drying spackle. Sands great and looked like I knew what I was doing. I was doing square edges though, I'm not sure how that would work with an ogee edge. Something sprayable is likely a better idea.

[Ole Anderson]

Shellac based primer: I am spraying in an enclosed garage in the winter, fumes will be an issue
Sher-Wood high build primer: an industrial coating with tons of warnings on the SDS. I'll pass, but thanks for the reference.
The routered ogee edge is actually quite smooth.
I simply don't have the time or energy to spackle and sand over 150 edges, so a high build primer will have to do. The Kilz Premium claims to fit that bill. This isn't a high end residential project, not looking for a piano finish.

[John TenEyck]

Shellac based primer: I am spraying in an enclosed garage in the winter, fumes will be an issue
Sher-Wood high build primer: an industrial coating with tons of warnings on the SDS. I'll pass, but thanks for the reference.
The routered ogee edge is actually quite smooth.
I simply don't have the time or energy to spackle and sand over 150 edges, so a high build primer will have to do. The Kilz Premium claims to fit that bill. This isn't a high end residential project, not looking for a piano finish.

The Kilz Premium might work well, it's 56% solids, if the water doesn't cause the edges to get rough and require a lot of sanding. That would be my major concern. A coat of Sealcoat shellac or BIN shellac based pigmented primer first might prevent that. I'd do some testing before spraying many doors.

If you wear a respirator with organics cartridges, using shellac is a non-issue in a garage, just crack the door. Likewise, it works at nearly any temperature since it "dries" by evaporation of the alcohol. With WB products temperature is critical to both drying and often curing, something to consider carefully with what products you choose.

John

[Jim Becker]

Shellac based primer: I am spraying in an enclosed garage in the winter, fumes will be an issue
Sher-Wood high build primer: an industrial coating with tons of warnings on the SDS. I'll pass, but thanks for the reference.
The routered ogee edge is actually quite smooth.
I simply don't have the time or energy to spackle and sand over 150 edges, so a high build primer will have to do. The Kilz Premium claims to fit that bill. This isn't a high end residential project, not looking for a piano finish.

That's reasonable, but you'll still need to sand all those edges and may need to spray a second coat.

[Ole Anderson]

So I used the Kilz 3 Premium. It did raise the grain a bit and required lightly sanding the face and edges. Airless spray using a 311 Graco tip with about a cup of water per gallon. Ended up going over the edges with a mini roller to add some quantity of primer on the critical edge. Finished up with Behr satin cabinet paint, same tip. Flattened out perfectly. Very happy with the results. I bought a roll of Duragold premium 220 grip hook and loop backing. Worked great on my Zip paper holder and worked even better on the curves handheld. That stuff never wears out and didn't clog on the vinyl primer. https://smile.amazon.com/dp/B08GFNDW...roduct_details