:>I dont know how shellac gets "crapped out" to not seal because you use
:> alcohol to thin it, maybe the wood is a bit green and an active knot
:I think it fails to harden properly after a while. Mixed shellac has a
:shelf life of about 6 months, but he canned stuff is longer.
:To answer the OP, I'd wipe the wood down with alcohol first, then apply the
:sealer, such as Kilz.
You can remove the shellac with alcohol, as recommended. What I did to
prevent problems in clear finishing my pine was to follow these
1. First coat: Very thinned down shellac, a 1/2 lb. cut.
2. Coat with boiled linseed oil and wipe dry with rags after a few
minutes (e.g. 15 minutes). Some discarded socks are very good for this.
3. Let dry - depends on weather, anywhere from 4 days to 2 weeks.
4. Two coats of shellac, followed by two applications of furniture wax
rubbed in with very fine steel wool.
After almost two years this has been very stable, no bleed through.