definitive sealing MDF

[sm_jamieson]

I'm still wondering how to seal MDF end grain. Ideas I've heard so far :- so-called MDF primer (water based) - raises grain, probably a rip-off Zinsser BIN - the best but expensive shellac - produces a hard finish doing away with the MDF "fluff" ? knotting solution ? So, whats the best thing to use - the sort the trade would use as a "trade secret" ? Cheers, Simon.

[John Rumm]

Knotting solution typically is shellac.

What sort of seal do you want? If it needs to be water resistant, then polyurethane varnish is probably better than shellac. For inside apps knotting / shellac would be fine.