lee

[Lee]

Does anyone have any experience with using shellac over old lacquer? From time to time when I apply shellac over an old lacquer finish the shellac becomes crazed. Is this due to incompatibility of the two, presence of silicon or the base surface not being cleaned sufficiently?
Thanks for any help.
Lee

[echnidna]

I have shellacked over lacquer quite successfully so I don't think its a compatibility problem.
Silicon usually creates "fish eyes" and not crazing.

So I suspect the surface hasn't been rubbed back well enough.

[ubeaut]

Don't shellac over old lacquer. Mostly they will move at different rates during temperature changes and with age which causes crazing. Wax on the surface of old lacquer will do the same. You really need to strip the whole thing of lacquer before shellacking or applying any finish.

Shellac is one of the only finishes that will adhere to almost any surface, because of this it will often craze with time when placed on an incompatible surface. I have used this to advantage in the past to create crackle or crazed finishes for decorative effect.

Cheers - Neil

[Lee]

Neil,
thanks for your reply.
When not wanting to strip a period lacquer piece, can another layer of lacquer be put over the top to improve the finish? Will it bond?

[ubeaut]

Would most likely flake and fall off pretty quickly as you have no idea what else has been put on the surface during its life. One spray of Mr Sheen will stop most finishes from sticking even if done 20 years ago.

The best thing to use if the surface is still in tact is Polish Reviver this will clean the surface and hide water marks etc and may save you the cost of stripping the finish from the surface. If this doesn't do it there is nothing for it but to strip and re polish.

Sorry but there really aren't any short cuts that work well if you want a good finish (refinish). Most shortcuts are just a shoddy quick fix, and will leave you a year or so down the track, wondering why you ever tried them in the first place.

Cheers - Neil