# FP.



## Digit (1 Nov 2009)

Too late now for the competition I've finally reached the stage of French Polishing the writing slope I was entering, but I have a problem. 
Locally FP is only available in medicine size bottles at nearly a fiver a shot. 
So I decided to mix my own as the raw materials are available. 
Nearly all the info on Google etc sort of starts with, 'Take one Gallon of alcohol...' 
Don't want that much do I? 
Anyway, how thick to make it, eventually I purchased a bottle and decided to compare viscosities. 
Next problem, how? 
I know how to do it with the pro equipment, which I don't have, so eventually I simply dipped a screw driver a measured depth into the stuff I had purchased and added flakes to the meths till I got the same drip rate. 
Success! 
How do you people do it? 

Roy.


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## Sgian Dubh (2 Nov 2009)

It sounds like you are hitting all the North American sites with instructions for mixing shellac. They talk of "pound cuts". By this they mean they dissolve, for example, 1 lb of shellac flakes in 1 US gallon of alcohol to get a "1 pound cut". A normal "cut" for applying shellac with a brush or rubber is a "2 pound (lb)cut".

If you prefer to work in metric dissolve about 250 grammes of shellac flakes in one litre of alcohol which is about the same as the American 2lb cut. You might know alcohol better by the name meths, the blue stuff you see at DIY places. I use it sometimes, but more often I buy and use industrial alcohol which is clear, the same stuff but minus the blue dye. Slainte.


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## Digit (2 Nov 2009)

Yeah, mainly the American sites I agree, but even a litre can be too much if as they say it won't keep.
In the past I have only used FP in industry, ready made, by the gallon and used to quickly for it to go 'off.'
It's odd that I can buy everything locally, even cotton waste etc, but unable to buy FP in other than tiny bottles.
Having said that I have never been able to buy other than Meths.

Roy.


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## Sgian Dubh (2 Nov 2009)

Digit":35ecoekv said:


> ... but even a litre can be too much if as they say it won't keep.
> Roy.



In that case you could work in half litres. Add about 125 grammes of shellac flakes to 500 ml of meths. If you like you can mix the stuff a bit thicker than this, eg, 200 grammes in 500 ml of meths. All you have to do in this latter case is thin it out with more meths if required when you use it.

You can purchase various forms of shellac in flake form from a range of people, eg, Axminster and specialist wood finish suppliers.

Meths is readily available from several DIY places, such as the national chains like B&Q or a local general hardware shop. Slainte.


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## Digit (2 Nov 2009)

Funnily enough, with two stores dedicated to wood work I have to buy shellac flake from jewson's!
I shall be working in half litres in future but the main reason I asked is that the different 'cuts' can be thinned for the later coats rather than waste the thicker 'cut' used at the start.

Roy.


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## yetloh (3 Nov 2009)

If you hate the small of meths as much as I do and don't want the purple clour any way, you can do the same as I do which is to buy "Finishing Spirit" from Morrells. They describe it as "A blend of alcohol and refined polish for use in the spiriting-out process. Its high alcohol content allows it to be used to thin shellac polishes." It smells better and works fine for making up your own polish.

Jim


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## wobblycogs (3 Nov 2009)

For my sins I was a chemist once... 

Meths contains a little more than just purple dye. It it mostly ethanol but it is denatured with a little methanol has a foul tasting compound called bitrex added and is coloured with that purple dye. There is usually a trace amount of benzene in it too from the production process (it's generally manufactured alcohol rather than brewed). 

I doubt any of the additional ingredients will make any difference to the finish but it's worth knowing they are there. The only one I wouldn't like in my finish is the dye. Looking at it I would guess that it probably emits strongly in the near UV so it will act as an optical brightener - they are the compounds that make your clothes whiter than white.


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## Digit (3 Nov 2009)

Actually I love the smell of Meths! :lol: 
Hic!

Roy.


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## yetloh (3 Nov 2009)

Oh well, it takes all sorts!. I guess the reason it smells different is that the finishing spirit is methanol based. Perhaps Wobblycogs could tell us if one is more toxic than the other - not that I am proposing to drink either of them. 

Jim


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## wobblycogs (4 Nov 2009)

The smell of meths will be from pyridine (forgot they added that as well). It has a fishy sort of smell which most people find fairly unpleasant. Neither methanol nor ethanol have much smell or taste. 

I don't know what's in the finishing spirit (could get the MSDS info but I don't fancy registering at the moment) but its description indicates it's probably based on ethanol with up to 10% methanol like most methylated spirits. I guess they just leave out the pyridine and dye. 

The denaturing of the ethanol with this concoction of methanol, pyridine, bitrex, dye and probably a few other things is so that our glorious rulers can continue to heavily tax alcohol that is fit for consumption. 

As for toxicity, NEVER even consider drinking meths or finishing spirit. Methanol is very toxic, if you are lucky you will be violently sick and go blind if you are unlucky you will slip into a coma and die. As little a 1ml of methanol (so 10ml of meths) will kill an adult. It was the only standard bench chemical that had "induce vomiting" on it's safety sheet because it was that important to get it out of your system quickly if you swallowed it. 

As for working safely with meths type solvents, a standard pair of latex gloves and a room with some ventilation should be adequate. The biggest risk, especially with pure methanol, is fire as they have a fairly low boiling point and the flame can often be hard to see.


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## Digit (4 Nov 2009)

> The biggest risk, especially with pure methanol, is fire as they have a fairly low boiling point and the flame can often be hard to see.


 
As a kid I made a rocket engine using Meths as the fuel, it worked a treat. Straight off the bench and into a pile of straw. 
That was when I understood that flames can have different temperatures, the flame was incapable of igniting the straw. 
Thankfully, as I doubt my dad would have been overly pleased with me! 

Roy.


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## Aled Dafis (4 Nov 2009)

Roy

The advice i gained from John Lloyd at Westonbirt last year regarding desolving shellac flakes, was to fill a jam jar to two fingers high with the flakes, and then add finishing spirits (meths) to double that height, or four fingers high. Simple.

My understanding is that finishing spirits is an alchohol, basically very similar to meths minus the purple dye, a little shellac is then dissolved into the spirit so it becomes a "finishing spirit" and therefore we don't need to pay duty to the government. I think that i read this in Fine Woodworking a while ago, but can't be sure, so don't quote me.

Cheers

Aled


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## Digit (4 Nov 2009)

Thanks Aled. I just posted on the Finishing thread that I have got a lovely deep colour and a high gloss, but lots of rubber marks, and I was just coming to the conclusion that my FP was too thick and intended trying a more dilute mix for finishing.

Roy.


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## Ironballs (4 Nov 2009)

The difference between ethanol and methanol is that one makes you fancy ugly birds and the other just makes you blind.

Richard where might a non-tradesman buy industrial alcohol, I assume it isn't readily available?


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## Digit (4 Nov 2009)

> one makes you fancy ugly birds and the other just makes you blind.



That's the same thing isn't it? :lol: 

Roy.


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## wobblycogs (5 Nov 2009)

I was looking into getting some chemicals for a little project I had in mind a few months ago. As long a you don't want anything on a restricted list I'm pretty sure there are small chemical suppliers that will sell to hobbists. I found a few on-line that looked promising and only appeared to require setting up an account, unfortunately I didn't think to keep a list :roll:


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## Digit (5 Nov 2009)

My problem at the moment is lack of expertise!

Roy.


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