I just finished a Subwoofer box for my car and im thinking im just gonna paint it black, unless anyone has a cooler idea. I know i need to seal MDF before i do anything to it, but ive never done it before. Can anyone point me in the right direction?
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Gracias! This is quite useful.
If you don’t feel like spending for general finishes, basically you just need to seal up the ‘end grain’ of the mdf. Any quick drying finish that hardens works. What you don’t want is an oil or long drying finish that will soak and cause the fibers to swell.
I tend to use the bottom of my cans of shellac. I’ve used minwax sanding sealer before as well, which worked well but bubbled up slightly, so that was annoying on the not-flat surfaces if you have detail carvings on your work.
For what it’s worth, a can of dewaxed shellac is a huge boon in your toolbox if you’re doing woodworking consistently.
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Many, many moons ago when I was building mdf, fiberglass and fiberglass/mdf enclosures the way we always did it was a 220 sand, three coats of high build filler primer with a 220 light sand in between then four coats of paint with a 320 light sand in between.
Finish with a 1500 then a 2000 sand moving to McGuire’s finishes and ending with McGuire’s show glaze.