Old shellac

[wood spirit]

Have some old 20+ years flake shellac -will only dissolve to a degree and leaves lots of solids on the bottom - has done this for ten years plus. Does it get OLD & can it be fixed, always had this problem with this batch - even to some degree when just purchased. can remember my 1st experience with shellac was at high school woodwork classes open jars -quite thick -well add metho. this stuff from new always seemed thin at best. i do know it's positives and problems. However still think that it has it's applications.
There should be many well versed in the stuff- Do I throw itf out and get new or what??:no:

[ubeaut]

The shellac at 20 years old is probably well and truly zonked out unless it has been stored in cool dark conditions.

Most regular shellac flakes will leave a slight residue when mixed but mostly it's a combination of dirt and a minute bit of shellac

If the solids look like soggy Corn Flakes the shellac is all but useless.

If you are using cheap methylated spirits from the supermarket even good shellac won't dissolve properly.

Ideally you need to use Industrial Methylated Spirits (IMS) aka Ethanol, with either 95% or 100% alcohol sold as 95% IMS or 100% IMS mostly only available from good paint shops and Mitre 10.

The stuff in the supermarket can have up to 47% water in it (from memory that's about right) as it only has to be over-proof: ie will burn if a flame is put to it.

If you put a little mineral turpentine in with your meths and shake it and the mixture goes even slightly cloudy or milky then it contains water and may not be any good for dissolving shellac. Even if it does work and you use it you may get bloom (a milky look) when it dries.

At 20 years old I'd be throwing it out and buying some new shellac. The new stuff will dissolve quickly and work really, really well.

General mix is 3lb shellac to 1 gallon of meths Roughly 220 gm to 1 litre of metho.

Hope this is of some help.

Cheers - Neil :U