(ed. Note: I don’t recall when I originally created this page – I suspect it was either just before or during the period when I was building the Octave Mandolins, because I had access to HHG and apparently made my first set of spool clamps. I did the first stage (described below) and then shelved it for quite some time. I recently took it up again (September, 2023) as I was preparing to do the finish on the Mandolins, and had questions about what finish to use for it…)
Stage 1
From a fiddle kit bought online – the kit was “in the white”, with all parts cut out, the top and back bookmatch joined and shaped, f-holes cut out, the neck cut out and shaped. The ribs were bent and attached to the back, c/w neck and tail blocks and linings.
I then;
- tap-tuned the top, and installed the bass bar.
- glued on the top (HHG). I had to make a bunch of spool clamps to do this, and figure out how to heat the glue.
- installed and trimmed the purfling.
- cut the neck joint and installed the neck (c/w fingerboard).
It now looks like a (unvarnished) fiddle. Still to do; install the hardwood piece at the bottom, where the tailpiece goes over the edge (it’s called a saddle), varnish the body (and neck?), taper the pegholes (if required), and install the tailpiece, pegs and strings. Not much, but all this takes time, much longer than you might think. One of the impediments is that I seem to have mislaid the varnish that came with the kit.
Stage 2, September 2023
I cut and shaped the saddle, then glued it in place and did the final shaping. (Note: apparently I wasn’t supposed to glue it in until the finish was applied, so now I will have to either unstick it, or mask it off for the finish work (the most likely path…)).
I then realized that I would have to remove the fingerboard to do the finishing, which was accomplished with the aid of a flatiron.
On removing the fingerboard, I discovered that there was still some shaping left to do on the back at the heel joint, and that there was significant gaps in the heel-side interface. A bit of plastic wood was employed to fill the gaps and the shaping was accomplished with a sharp chisel and sandpaper. I do still have to sand the edges smooth, and re-sand the whole thing so that it has a consistent base colour (it darkened somewhat from oxidation, but I cleaned up the edges when I installed the purfling, and that is lighter). So. I need to sand smooth the edges, and then re-sand the top to clean that up. And then i should let it hang in a south-facing window for the winter, and take up the process in the Spring/Summer, so that I can UV-expose it after varnish coats.
Finishing
I originally considered just using the water-based finish I use on mandolins for the fiddle, however a bit if investigation reveals that small instruments like violins show considerable benefit sonically when the appropriate finish (varnish) is used. There appears to be as much material on the subject of finishing of violins as there are violins in the world! And there are a variety of aspects: use of sizing (a protein-based sealant as the first layer of finish), when and how to add stains, what type of finish to use, etc. I’ll try to address each aspect separately, and then summarise with the approach I will take (and why).
Oil vs Spirit Varnish
For a really good treatise on the evolution of violin varnish, see this article in Strings Magazine – “A Look at Parisian Violin Makers’ Approach to Varnish”.
Spirit varnish is what was originally used in instrument making:
“The makers of the late-18th century, considered the old Paris school, generally used varnishes based on seed lac with an addition of gum sandarac and gum elemi, all dissolved in alcohol with perhaps the addition of a small quantity of essential oil that covered a base coat of parchment glue-size. These varnishes were fast drying and did not need sunlight to bring them to perfection as oil varnishes do, but they can lack the light-transmitting and illuminating characteristics that oil varnishes have by nature.”
https://stringsmagazine.com/a-look-at-parisian-violin-makers-approach-to-varnish/
Spirit varnishes are still used today, but generally only when doing touchups, because of the fact that they are fast-drying, and also that they can be prepared fresh when required with minimal effort.
Oil varnish is generally recognised as being vastly superior as an original finish for various reasons. As mentioned above, the appearance is superior. Sonically, oil varnish also appears to have the edge. And it keeps better on the shelf – spirit varnish generally needs to be made up fresh for each use, with a shelf-life in the range of weeks once exposed to moisture-laden air. Oil varnish can apparently be kept for decades (which is a good thing, given how difficult it is to make..)
Speaking of which, see here for a YouTube video of how one luthier cooks up his oil varnish. The method described there relies on extreme heat to render out various raw ingredients to the purity required and to cause them to combine in the manner required. The process is dangerous, smelly (as in ‘putrid’) and has varying results for the home DIYer. See here for another demonstration, which uses more time (weeks) to achieve the same result. This one also describes how to wash the linseed oil. I personally recommend purchasing from a supplier you like and sticking with them.
Ground/Sizing/Base Layer
One thing I encountered a fair bit in my research is that more important than the type of varnish used is to also include an initial base layer. The term ‘size’ (sometimes ‘glue-size’) is encountered frequently, and originally referred to a technique developed by artists (‘glue-size’ – see wikipedia) when painting on cloth. Cloth, typically linen, is prepared for use by applying a layer of glue (typically hide glue) to create a surface that does not absorb the paint pigment. The glue-size seals the linen. Glue-size is also used in woodworking, to seal a wood, raise and fix in place for final sanding any loose-end wood fibres and give it a surface that does not overly absorb other liquid products, such as other glues (see here).
In the world of Lutherie, it has been discovered that the Cremona masters (Amati, Stradivarius et al) fell upon the use of sizing to prevent varnishes from saturating the wood fibres and thereby inhibit their vibrations. The result is a better-sounding instrument (apparently). The actual material used in their sizing is unknown, but it seems to include some sort of animal protein. Today the use of some sort of sizing is de rigeur, however the actual material used varies a fair bit. Some folks swear by ‘Vernice Bianca’, a mixture of egg white, Gum Arabic and sugar or honey, while others use albumin (egg white protein), gamboge (another resin) dissolved in alcohol, hot hide glue diluted to a 10 percent solution or thinned gelatin which is pretty much the same thing, a drastically thinned down coat of whatever varnish you are using, or thin shellac. Atlantic Violins, where I intend to obtain my varnish, sells a gelatin powder “for sealing new wood”. I’m currently torn between using that or making my own albumin…