Ervin Pergjergji
Zinsser B-I-N sealer & stain killer is the best on the market, dries just in 15 minutes, recoatable in 45 minutes. Only problem with this sealer is - you have to use cheap brushes as you can't clean them after. In my opinion i would avoid to use undercoat or any oil based paint because it take ages to dry and it's really hard to cover with the top paint afterwards. Hope this helps.