Meths vs. Turps

[srs]

Meths vs. Turps

So what’s your preferred? no not to drink!... For dissolving shellac in up till now I've always used pre mixed shellac but I picked up a couple of bags of shellac flakes at the weekend so thought I would give it a go s I only use a small amount now and again I can mix it as needed. Also do I need to add the boiled linseed to the shellac or just a little dab as needed?


Cheers
Simon

 

[Alf]

Meths. Well actually the colourless stuff for pale shellacs. Chestnut do a "Spirit Thinner" that works admirably. Isn't Turps something all together different; more like white spirit? I always get hopelessly confused with the technical side of finishing. i.e. all of it... If you're French Polishing you might well need a dab of BLO occasionally, or so I understand. But if you're trying that, I advise getting hold of some detailed info on the process, which should tell you all you need to know with regard to solvents etc too.

Cheers, Alf

 

[Chris Knight]

Shellac won't dissolve in turps - it dissolves in alcohols (meths in the two things you mention. There is no need for linseed oil.

See here for some explanations http://antiquerestorers.com/Articles/jeff/shellac.htm

 

[Scrit]

Meths. Well actually the colourless stuff for pale shellacs.

Clear meths is difficult to get it these days, even in trade quantities unless you hold the appropriate licence. And as you say Turps (or oil of turpentine) is an entirely different beast - it is derived by steam distallation from the oleoresin exuded from the sapwood of pines (mainly in the USA), with its chief uses being as a constituent in paints and varnishes. Meths (or methylated spirits) is ethanol with small quantities of methanol and pyridine and of course that purple analine dye. The purple stuff was added as a result of the Revenue Act 1889 as a means to (according to Hansard) "address a problem of people purchasing and drinking methylated spirits on a day when dutiable alcoholic liquors were not readily available" :shock: . In fact the purple stuff (meths) will still make acceptable French polish, especially with darker shellacs. So if you are concerned about the colour, best just keep buying the ready-made stuff. Funnily, whilst almost every country in the EU seems to insist on adding a dyestuff to meths, the French do not - see here.

If you're French Polishing you might well need a dab of BLO occasionally...

Yes, but only a few drops to lubricate the rubber (not added to the polish), and only with the second or later coats I was taught. Depends on who taught you, though.

Scrit

 

[Alf]

Meths. Well actually the colourless stuff for pale shellacs.

Clear meths is difficult to get it these days

Don't I know it - but the Chestnut stuff is clear and seems to be fine.

If you're French Polishing you might well need a dab of BLO occasionally...

Yes, but only a few drops to lubricate the rubber (not added to the polish)

Oops, yes. That's what I meant, bit sloppy there.

Cheers, Alf

 

[Keystone]

Thanks for that Scrit. I had no idea that you folks on the other side of the big pond had problems getting Alcohol. Here in the States Denatured Alcohol is easy to purchase. DNA runs about $10 US per US gallon. It is clear but does have something added to it that will make one sick if they were to consume it.

 

[srs]

Cheers for the info I was supprised that we have been dyeing meths for so long I just thought it was somthing that was brought in after WWII.... well you live and learn don't you.

 

[edmund]

For those of you who are interested, there were some new regulations that came into force earlier this year which replaced the Methylated Spirit Regulations 1987 - now the Denatured Alcohol Regulations 2005
http://www.opsi.gov.uk/si/si2005/20051524.htm#13
Meths is no longer called meths. So, MMS is now "completely denatured alcohol", IMS is "industrial denatured alcohol", and denatured ethanol is "trade specific denatured alcohol". As per the old regulations it sets out the recipes for these. To buy anything other than what was formerly called MMS you need to get written authorisation from HM Customs. Don't know why we can't do it like the Americans...
So know you know. Sure you'll get a baffled look when you next go a ask for a couple of litres of completely denatured alcohol from your local supplier