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Subject:
Re: Scorched Earth Advice on Shellac

Sgian Dubh
" ... I came across some gurus and their articles about things and I just wonder why they feel the need to express some definitive opinion about something that's probably not that definitive in reality.

...'"there's no reason to ever buy anything other than dewaxed shellac"', and a subsequent discussion about why waxed shellac is actually inferior."

I suspect those "definitive opinions" about dewaxed shellac are some sort of misunderstanding. There is one situation I can think of where using dewaxed shellac is generally a safer option than using a regular waxed shellac, and it relates to the use of shellac as a barrier or primer coat between a suspect base wood, e.g., a waxy or oily surface, silicone contamination, resinous wood, etc, and a subsequent preferred finish, such as pre-cat lacquer, oil varnish, a water borne varnish, etc.

Shellac is very good at adhering to various types of suspect surfaces: it adheres very well to all sorts of challenging bases, as well as adhering well to good clean surfaces, and as such can act as a primer or sealer coat to keep more finicky finishes away from something that would otherwise cause them to fail one way or another.

Many other types of finish adhere very well to shellac, whether it's the waxed variety or the dewaxed form. But, I'm aware that some of the waterborne finishes are reputed to not adhere well to waxy shellac, but will stick satisfactorily to the dewaxed variety. So, there's a theme that the general advice to inexperienced finishers being that, if you're going to use shellac as a barrier coat as just described then it's best always to use the dewaxed variety, and this will ensure satisfactory adhesion of any other type of finish that is subsequently applied.

So, my theory is that the dewaxed only mantra you mentioned comes from this source. As to which form of shellac is generally better for shellac only finishing, whether sprayed, french polished, brushed, etc, I don't have anything 'definitive' to say on the waxy or dewaxed shellac debate. Surely it's a case of picking the type of shellac to suit the polishing task at hand, rather than limiting yourself to one form or another ... isn't it, ha, ha. ? Slainte.

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