Primer and paint on mdf?

[Bent]

I'm close to being ready to prime my new subwoofer enclosure


the majority of the filling has been done (tedious process that is...) almost all of the work with the roundover bit is finished and I'd like a suggestion for a suitable primer to use prior to painting.

I don't know how to get sketchup to do a "bullnose" so I'm going to ask that you use artistic lisence to imagine the top, but the top edge will have a 1" radius bullnose all the way around it with the top panel flush with the bullnose, so will the bottom perimeter have the same bullnose. The remaining surfaces will be trimmed with matching square trim. and the drivers will be re-based 3/8" of an inch by the matching grain tombstone.

I haven't drawn it yet, but the base will be a substantial plinth approx 1" wider than the enclosure but with a pedestal 1.5" tall but 1" smaller than the 22"x22" enclosure.
Here's the sketch.



Would I prime and paint the entire enclosure prior to attatching the tombstone and trim, or should I mask the enclosure after installing the trim?

What bramd primer should I look for (spray on would be preffered, but I certainly can roll something on.
Afterwords, the actuall paint will likely be Rustoleum's "hammered" finics or self applied bedliner depending on how coarse the texture will be. (I'd prefer a little coarse, but not a lot... so it winds up looking like stucco.)

Thanks in advance.

[Silversmoky]

I am not sure I have it pictured entirely correctly about what you are doing but I think I would definitely prime and paint before attaching your other trims. Masking can be a pain and usually doesn't turn out as well in my experience.
I have used several different primers on mdf. It is so absorbant that I usually prime twice. The best that I have liked is Zinnser. I use a can spray gun with my compressor but it sounds like your finish will not be smooth so for really good coverage I would probably roll it on. It dries very hard too. It is also in cans if you prefer but coverage won't be as good. BTW nice looking enclosure.

[Bent]

Can you think of any possibilities where the trim I intend to attach would not stick well to the paint/primer on the corners? (this is assuming I glue the trim on only, as I don't yet have a brad nailer - I'm not averse to using a brad nailer and filling the holes with matching wood coloured putty afterwords.)

[Edge540]

the greatest stuff to use prior to painting MDF is a product called Feather Fill G2. Its about $50/gal. from an auto paint store. youll have best luck if you scuff the shiny face of MDF with say 220 grit then blow everything off very well. Use a brush to hit the exposed MDF edges with FF to fill the pores. With the edges not yet cured completely, spray the entire enclosure with FF. Feather Fill is basicly a polyester sprayable Bondo material. Very high build rate, and very easy to sand.
Works great!

[Silversmoky]

I don't think you will have any problems with glueing. Should work great. I was picturing using a brad nailer but either will work fine.