Spirit Varnishes

[Mark Elliott]

When you guys have to match an old spirit varnish,  what do you use as a base?     I had to match a finish that at it's darkest is a cordovan color.   At it's lightest,  it is a reddish brown.  It is over AF that is applied to very reddish maple.  I have made up red violin varnish before, but it is a lot of work.    This time,  I worked up a close color match by using a 2lb cut of orange shellac and dragons blood.   A black oil wash under the spirit varnish will give the cordovan color.   I tried the orange shellac because I already had it mixed up.   If I hadn't,  I probably would have made a small batch of violin varnish.   The problem is that spirit varnishes don't keep very long whereas oil lasts until I can use it all up.

[Dr. Tim-Boone]

Make shellac in very small batches as 6 mos is about all you will get from it. 
here is a quote from a luthier... go to his site and check out what his finishes look like

"From LUIS CLAUDIO MANFIO
Posted on August 2, 2008 at 01:12 PM
Spirit varnishes may be good or bad, the same for oil varnish. I would not like to use an oil varnish that never dries completely on my violin, neither an spirit varnish that is too "dry". I find the final result of oil varnish better, that's why I use it and there is a trend towards oil varnish, but many makers in Italy prefer spirit varnishes.

In my process I use an oil varnish based on a 1550 recipe in the Biblioteca Marciana, Venice, it's two parts oil, one part colophony and one part mastic. I make a paste with this varnish and pumice and burnish it into the wood, it makes quite a reflexive ground and is good for sound, I think.

The final result in terms on sound will not depend only on the varnish, but model, wood, archings, set up and the experience of the maker.

You can see pics of some of my instruments here:

http://www.manfio.com/index_files/Page341.htm

[E.vonAschwege]

I too only mix shellac in very small batches.  I use seedlac only because I have a huge container full of the stuff, which imparts a darker amber color than refined shellac. 

For developing richer colors than stain alone, particularly for highlighting carving and minor wear areas, I've been experimenting with a combination of stain/dye before I start the finishing process, and then continuing to add bits of flavor here and there as finish layers are applied.  Much like a painting, the final product is found in the many layers of pigment applied sparingly on different parts of the stock.

Lamp soot is one of my go-to "colorants" to darken areas before and during finishing, and I like red-iron oxide pigment as well, though too much begins to look like paint.  Aniline dyes can also be of great use to tint the wood prior to finishing with a pigmented oil or shellac.  They can also be added to your shellac mix if you have alcohol soluble dyes. 

I've mulled different pigments into small batches of oil varnishes that have kept for ages, but the pigments tend to settle out sometimes and must be redistributed before applying the oil. 
-Eric

[Dr. Tim-Boone]

Eric do you mix the soot in some finish or lightly dust it on wet finish?   I have a container of very fine bone black and want to experiment with it to shade some areas

[Mark Elliott]

Tim,

I use lamp black artist's oil paint for black on my guns.   That paint consists of two ingredients; lamp black and linseed oil.  It is easier to control than graphite or charcoal powder which I also use on horns and bags and sometimes inside patchboxes.   You will get a rough/splotchy appearance with the powder that most people wouldn't want on a gun stock.   However,  it certainly would a good thing to use if you where going for something that really could pass for an original.   

Mark

[E.vonAschwege]

Tim - I have done both, it depends on what kind of effect I'm looking to achieve.  Soot mixed into the oil/varnish will be a thinner appearance than soot smoked over a wet finish.  On the otherhand, soot applied over a wet finish will rub back to the color underneath, while a series of layers with soot (or any pigment) mixed in will create a more gradual appearance of tarnish and wear.  Sometimes I just soot the whole gun over a rich burning oil lamp and rub that into the wood, then finish on top of that! 

Mark - I have also played with artist oil paints, but don't like spending the time to wait for the linseed oil paints to cure - unlike a canvas, I need to be able to handle the stock.  What do you use to accelerate the drying of oil paint besides using incredibly thin layers (which in my experience still takes a while to dry)? 

-Eric

[Mark Elliott]

I use very thin coats and mix with my normal stock finish which has a dryer.   It still usually takes two days to dry.   It takes a very long time for me to complete the wood finish on a gun that I am repairing or restoring.   

[Mark Elliott]

Eric,

I  am not really happy with how the artist's oils have been working for me.  They take a long time to dry even with dryers, and they are hard to rub back evenly.   

i have two guns I am re-finishing in the shop right now after some repairs/restoration and I decided to try using some powdered charcoal on top of an thinned oil finish.  I will see how that goes.   I have got to let it dry and rub it back some to see how it holds up.   

The way I have been going about it takes a couple of weeks to age/match finishes.   It is very tedious.   Just a little faster drying would help, but I don't want to use anything that isn't at least similar to original finishes.   I have been using oils for blending and touch up, but in general,  I like to put oils over oil and spirit over spirit.    It is a continual learning process.   

Mark

[heinz]

Mark,  I sometimes collect soot from a candle in a spoon held over a flame. I believe you mentioned having a carbide lamp, which would be better than the candle. I use turp and linseed oil on a rag and pick up the soot as needed to rub in.
I believe you will find that the lamp black or soot has finer particles and a little pre blending with PAHs that improve its performance over fine pure carbon.