Ok, here is the recipe I use for making a casein/oil emulsion (You will have to increase the amount for a cello.):
a) 1 gram casein (Nat. Casein J0-3)
b) 3 g water. Stir and wait 1 hour
c) Add several drops household ammonia (Piggly Wiggly Brand. Don't know the concentration. Stir and add ammonia until it is relatively clear. Maybe 10 drops.
d) Add water for a total of 10 g of the water phase
a) 0.3g lecithin + 0.7g Xylol …. stir until lecithin dissolves
b) Add lecithin/Xylol solution to about 10 g thick varnish. (honey consistency) Stir.
c) Mix water phase into oil phase while stirring. Result is a stable emulsion. It is thick now. You may add water to thin. Test by applying to lined paper or newspaper.
On the bare wood, I applied dilute Venice Turpentine (horse linament, which is probably pine rosin with some mineral oil). This VT was very dilute in pure gum turpentine. UV for some hours. (Sorry to be so vague.) I doubled the above casein/oil recipe for the viola. Maple of the viola had been exposed to intermittant sun over the course of more than two years. The sides colored much more than the back.
First coat of the emulsion/oil, using ACE Spar varnish, -- apply mineral spirits, then casein/oil emulsion. I use a sponge. Expose to UV for more than 12 hours. Then high rubble was scraped off. Second coat of emulsion applied, no mineral spirit this time. Another 12 hours of UV. Sanded with #600 paper. Now Conservation Support Systems Orasol Yellow 3R, which I believe is the same as Kremer's 94402 Yellow 2GLN sun gold, in denatured alcohol applied using a small section of paper towel or small sponge. Allow to dry. Next, thickened ACE Spar Varnish applied with finger. Result is very nice look, though obviously it is yellow slightly brown, and needs some combination of red/brown over it.
Measure 4 or 5 parts by volume (I use a 1/8 teaspoon measure) casein into small container.
Add enough water to cover. After a few hours, the casein will swell. Add enough water to keep it just barely covered with water.
After maybe 5 hours, you can add 1 part (1/8 teaspoon) Ms. Wages pickling lime. Stir. After a few minutes, maybe even 5, you will notice the consistency has changed. It should be smoother. You might want to use a small mortar and pestle to grind out the lumps.
Now you have casein glue. If you use this as a ground, you should thin it out. I leave it up to you to experiment. But before you apply to wood, put turpentine on the wood. Apply the casein while the turpentine is wet. This ensures that the casein will not penetrate. You probably want to add the Silex into the casein before applying. The casein shrinks down VERY much. Try putting a thick drop on glass. You will see that it dries down to a very thin coating. Of course you should try all this on scraps BEFORE you apply to an instrument. The above amounts (1/8 teaspoon) is for testing. For a cello, obviously you will want more
January 5, 2014
William Johnston rosin + sugar sealer color. Plus casein ground.
As per William's website, place 1 tablespoon rosin and 1 tablespoon sugar in a can. Heat slowly on hotplate (outside). At some point the mix bubbles, foams up and turns black. Remove from heat and cool. Add denatured alcohol, or alcohol. This solution, applied to maple, gives a bit of color and enhances the figure. Apply the above solution to maple. Perhaps 2 coats. (This is the sealer)
Next, take 1 teaspoon JO-3 casein, add enough water to cover the casein. Wait 1 hour. Add a little more water. Stir for 1 minute. Add 1/4 tsp. Mrs. Wages pickling lime. Stir for 3 minutes. Perhaps add another 1/4 tsp lime. Stir. Add 1 tsp slaked plaster. Stir. Apply, by rubbing, to the maple which has been primed (sealed) with the rosin_sugar sealer. Add dry slaked plaster directly to the wet casein/plaster. Rub more. Burnish into the wood with some sort of burnisher. (your call).
Remove excess. Allow to dry.
Rub with 400 grit paper. Apply some gold alcohol based dye stain, Transtint honey amber, available at fine woodworking stores. Or the yellow stain of your choice. At this point, the maple is very smooth and filled. Almost could be used as a final finish. Joe Robson's amber varnish, which, to me, is yellow brown, rubbed on, looks great. But I would want to add some red over this brown. My taste only.
So far, my result looks good.