MDF Sealer

[htoby94]

I am in the process of building my first cnc machine using mdf and am new at this all round. I am wondering what is a good sealer for mdf.

[CNCadmin]

You can use just about anything, start with a sanding sealer than a clear polyurethane.

[ger21]

What kind of topcoat will you be using?

[anoel]

Shellac... Yeah, definitely shellac.

It'll seal things up without causing it to swell since it's alcohol based. As opposed to a water or oil based sealer. And Shellac dries in just a few minues and will accept "ANY" kind of paint very well.

[sol]

Yeah, like he said! Yes, I know I am repeating anoel...'cause he is right.
Shellac primer is the answer. It dries in minutes so the MDF does not act like a paint sponge. It seals out moisture unlike other primers, and it takes the final coat very nicely. BIN is a brand available around here; sold as a knot and smoke sealer...careful though, not all knot sealers are shellac.

Latex final coat is fine, Something semi or gloss for the final will be easier to keep clean.... leftover exterior house paint will work well too.

Edit:Spell-check

[htoby94]

Thanks guys, I'll try that!