Hardener, to formulate Hard Shellac, for 500ml

Additive to be added to a 1:4 shellac weight to alcohol volume mix. Cross links in about 20 days and forms an extremely tough final coat significantly harder and more resistant to skin acids than standard shellac.

Notes updated January 2010
(Terminology: For the purposes of these notes 'Metho' = Methylated Spirits = Alcohol = DAA = Denatured Absolute Alcohol = spirits = ethanol)
HARDENER FOR SHELLAC SOLUTIONS.
After shellac has been dissolved in ethanol it is possible to introduce additives that cause the shellac to cross link over a period of about 20 days. Note that this crosslinking process can be shortened within reason by 2.5 days for each 10 degree Celsius (50 degree Farenheit) increase in temperature with lights or a heater.

This additive has been mixed to be appropriate for maximum hardening. It is added after the shellac has been put into solution. The hardened shellac can be used on table tops so that condensation & heat rings do not occur. Also increases resistance to alcohol. The additive must be in intimate contact with the shellac solution for 72  hours before the hardened shellac can be used. Application gear must not be allowed to go dry otherwise brushes, rubbers & spray nozzles will go rock hard. Wash them out well with metho. For heat resistance on window frames, tables etc, every coat should be with the hardened shellac. Process of application & coating intervals of hardened shellac is identical to unhardened shellac. When using a rubber apply some oil on long strokes to prevent tearing. This additive slightly slows the drying process which reduces blooming & allows for a brush to be used on large surfaces without the "edge" drying before you have time to get back to the start point. Note that the hardener cannot be fractionated.  Use all of the additive in one mix, as the hardener ingredients will not stay in their correct proportions while attempting to decant a part portion.

SHELF LIFE - hardened shellac can be treated as non hardened shellac for the purposes of shelf life. We recommend orange shellacs should be used within 24 months of being made up and the blonde and white grades within 18 months.  Refrigerate both flake and made up polish. Shellac is an organic product.  Do not freeze.

MIX RATIOS - This product assumes you are starting with a polish made up to a 4:1 ratio weight of flake to liquid volume of alcohol (e.g. 1  kilogramme flake to 4 litres of alcohol or 2.2 pounds of flake to 1.05 gallons of alcohol).  The portion of hardener supplied should be topped up to 500mls total liquid volume.

THINNING - When the hardened shellac mix is made up as advised above it can then be thinned as desired for use. The use of 100% denatured absolute alcohol (DAA spirits on the Australian market) or IMS  (Industrial Methylated Spirits  - usually specified to be 95% proof) is strongly recommended. Hardware store methylated spirits may contain unacceptable amounts of water which can cause blooming in the finished work.  

TOUCH UP & RESTORATION - Hardened shellac cannot be treated as normal shellac for touch ups and re-coats. In this respect it is similar to catalysed varnish finishes. Recoats outside the 20 day application window will not meld with the older polish.  Scuffing the old surface to form 'tooth' may be attempted.

TOXICITY - Given that the ethanol has off-gassed this hardener does not affect the toxicity of the shellac base which is rated as food safe and widely used as a pharmaceutical, confectionery and fruit glossing agent. It is rated as a food by the US FDA.

CONTAINERS - Export orders may be filled with smaller bottles for mailing efficiency. We will supply all customers outside Australia via Sea Mail.  The hardener supplied should be made up as described above to a total solution of 500ml.