French Polish Recipes

[Steve Dethick]

Have any of you guys ever used other gums or resins with shellac to make French Polish?

I am using an experimental mixture on my current project that shows great promise. It is basically alcohol, button shellac tops, and gum benzoin.

I obtained pure ethanol from a high school lab supply, and dissolved the shellac and benzoin in two separate batches. 150 grams of button shellac (minimal processing) is disolved in 500ml of alcohol and allowed to stand for a couple of weeks so that wax and debris can settle, leaving a dark but clear liquid on top. This I guess is pretty much a dewaxed shellac, but deeper in colour than the commercial stuff, and as such does not have the ability to expand and contract like ordinary waxy shellac. This is where the softer and more flexible benzoin gum comes into the equation.

15-20 grams of Gum Benzoin is now disolved in 200ml of alcohol. When disolved, and the debris allowed to settle (1-2 hours), benzoin gum produces a totally transparent solution that is flexible and takes the place of the shellac wax in the French Polish, without clouding the finish in the slightest way. The clear liquid is now decanted off both the shellac and benzoin and mixed together. Discard the debris, wax, and small amount of degraded polish remaining in the two mixing vessels.

Because of the addition of small amount of benzoin and removal of shellac wax, the polish has a much higher gloss, builds better, is totally transparent, and seems to work easier with the rubber! Plus the benzoin smells better (vanilla ice cream!!)

Hope this is interesting for some - Any comments or other recipes?

[markharrison]

Welcome to the board. I live just up the hill from you in Bilgola Plateau.

Interesting process. I've not heard of this before. Where do you source benzoin from?

[rsser]

Read about it Steve in a p/c of a hundred year old text on French Polishing. Full marks for experimenting!

Seems like a lot of stuff can be added to shellac for different purposes.

(If pushed I could try and find the text and post some other recipes).

[Steve Dethick]

Benzoin Gum comes from a tropical asian tree, and is widely used in inscence as a bonding agent, and can also be burnt by itself giving a lovely honey/vanilla scent. In polishing it gives a very high gloss when used with shellac in small quantities. It is more flexible than dewaxed shellac, and does not have the wax content, hence it's use as a replacement for the wax in this recipe. This creates a polish that is absolutely transparent while still retaining the beautiful shellac tone (benzoin when disolved is almost colourless, a pale yellow).

Benzoin gum can be ordered in natural lumps (like amber), or in powdered form from a number of aromatherapy and new age sites (I don't subscribe to that stuff, but if they sell good to polish with....).

http://www.pygmypossum.com.au/products/view/item.html?id=931
These people sell the powder and lumps, at good price, but only in small quantities.

Mark, I used to live on the Plateau myself, would be good to catch up one of these days.

Steve.

[kiwigeo]

Benzoin gum can be ordered in natural lumps (like amber), or in powdered form from a number of aromatherapy and new age sites (I don't subscribe to that stuff, but if they sell good to polish with....).


My wife nurses in a hospice and uses aromatherapy on many of her terminally ill patients.....most of her patients do find it beneficial in easing their suffering. I might add that Im a cynical skeptic by nature and dont have much time for crystals and other new age w*nk...aromatherapy however does seem to have something going for it.

[ubeaut]

What you are making is basically the old coffin makers mix. Gum benzoin was added to keep the mix a bit soft and make it easy to pull a few rubbers of polish over after the coffin had been transported which usually left a few scratches and marks in the surface. It builds faster and is shinier but is much softer and not as a rule used for furniture that requires a durable finish.

You can also add oil and a few other bits and pieces to shellac and some manufacturers do. Our hard shellac has a melamine mix added to it. You can also add such things as n-Butanol which helps the shellac flow better or a plasticiser for some dewaxed shellacs to make them a bit more pliable.

However the best by far is fresh shellac mixed with 100% metho and nothing more. My favourite - dewaxed white (bleached) shellac. Builds very quickly to a bright shine, won't change the coliour of the wood any more than wetting it with water and is the toughest, most durable and longest lasting of all the shellacs.

Cheers - Neil :)

[Steve Dethick]

Neil, thanks for the insight. I have used 100% pure ethanol as the solvent, which may have helped with ease of application, though it is hard to come by (bottle stamped "not for sale without customs certificate" or such).

I knew Gum Benzoin was softer than shellac, do you think that the small amounts used (~5%)would affect the longevity of the finish, as the piano I'm restoring won't see much physical contact to the finish?

What is the purpose of the Sway in the Vitriol finish (see other post re. piano finishing)? Can a vitriol finish be done without benzoin?

Steve.

[Steve Dethick]

Yeah, I've read of many old recipes that have all sorts of stuff in them, linseed oil, Copal Manilla, Gum Benzoin, even Amber! if you could find it!

What interests me is whether or not any of these old recipes were any better than the basic shellac we use today, and if there were good and bad points to them. I read an article somewhere written by a conservator for some museum who was adding UV filters and synthetic resins to shellac in french polish, and achieving some marvelous results.

I guess the main problems in experimenting with these recipes are finding them, and finding the ingredients. I have enough trouble finding decent solvent.