Violin Forum/Message Board

[Geemac]

If I boiled linseed oil with the resin for a bow then cooled it and added turpentine, would I have varnish. What if I used the dried sap from a spruce tree as resin for varnish? Where can I get resin for varnish? I'd like to make my own varnish and not to buy ready made.
_________________
GeeMac

[M.Lange]

I have never made varnish so far. So take my comments carefully.

I don't know if bow rosin is pure colophony, but basically it should work.
Although it might be better (and cheaper) to use colophony.
As far as I know, many old varnishes (in Violin making and painting) contain Linseed oil, Venetian Turpentine or Colophony and mastic.
Mastic is said to improve the varnishes connection with the wood and makes the varnish homogeneous. So you may want to add a bit of mastic.

The cooking temperature and time has a huge effect on the properties of the varnish f.e. drying time, brushability (is that a known english word?), texture...
A longer cooking time or higher temperature will give a shorter drying time but will make it harder to brush.

Maybe others, who have some experience in making varnish, can comment on temperature and cooking time. It would be interesting to know the limits. (something like: "never let it get over 250 °C" or "cook it at least for 5 hours" would really be a big help)

A very good supplier is Kremer Pigments. they have got everything.
They even have a shop in NY:
http://kremerpigments.com/shopus/index.php?lang=ENG

Matthias

Edit: Luscombe violins sells some resins, too.

[Andres Sender]

It doesn't make sense to set out to make varnish without doing a lot of reading first. Don't try this dangerous process based on a smattering of forum posts--do your reading. Making your own cooked varnish is not a shortcut to be pursued with minimal preparation.

Bow rosin has adulterants in it, so making varnish from it would significantly compound the uncertainties already present in the process.

If you just want to get some varnish as quickly and simply as possible track down a commercial non-polyurethane varnish and use that. Some spar varnishes are apparently still made with phenolic. Behlen's Rockhard tabletop varnish is often mentioned, it's a phenolic varnish but it's short-oil so you'd want to experiment with putting more oil in it.

If you want to make varnish, get Michael Darnton's article(s) on varnish and varnish-making from American Lutherie, and read William Fulton's book "Turpentine violin varnish"--the general varnish section is very useful. I believe he is still selling copies, you should be able to reach him through the Southern California Association of Violin Makers. Here's an article of his on his varnish recipe, it will give you an idea of what's involved in the cooking process:

http://www.scavm.com/Fulton.htm

Further ideas will be found in Keith Hill's article on his varnish, found here: http://www.instrumentmaking.keithhillharpsichords.com/hillviolinvarnish.html

[DonLeister]

I found this supplier that looks very interesting, since I'm also interested in using raw resin. I have not bought anything from them though.
If I had the time to collect my own resins I would.

http://www.naturallist.com/pinesap.htm

[Andres Sender]

Ah that's cool Don, I looked for quite a while last year for something like that, so I wouldn't have to track down a pine tree.

Now I must dig up the article on making a varnish from pine sap and oil that was in The Strad in 1988: lute maker Peter Forrester was the author.

Then I'll have to decide whether to make and use it despite all the people who say such a varnish won't be stable.

I have heard from various sources that some spruces have been tried and didn't work too well as varnish. Pitch pine (which may or may not be the species the linked product comes from) was also somewhat suspect. I'll try to track down the correct species name.

[Andres Sender]

Well here you go GeeMac, someone's tried it. Back in 2007 over at Maestronet Jacob posted this: "I've even used cheap violin rosin, cooked in linseed oil a-la "Fulton". In the latter case the varnish darkens considerably on the instrument within a short period of time - from light amber to dark brown. Other than that it yields a perfectly good varnish. "

Ran into it while I was chasing up references to pine resin defects.

[Geemac]

Thank you folks. Your comments have helped this amateur nicely. I'm retyred and have plenty of spare time for experimentation.

I also have two large spruce trees and a pine tree in my yard. So, the first thing I'll do when spring arrives is tap the trees and collect the material. I don't care for a dark coloured violin, so I'll skip the bow resin. I have a cedar tree too. I wonder what cedar goo will do? Ground amber might be a source too.

Above all, keep having fun folks. Life's too short to waste being angry.
_________________
GeeMac

[DonLeister]

I remember Jacob commenting about some varnish he made using bow rosin, but my impression was that something didn't work.
From what the above post says, it seems that it did? Oh well.
Let us know what happens if you make up some varnish Geemac.

[Michael Darnton]

Andres, Don, the problem with using raw pine/spruce saps or rosin involves ugly crazing developing in several years. I've seen this, so I do know it's true. On the other hand, I have seen good varnishes made with these materials. The difference is in how the resin is prepared. I *think* it's the acid in the resin that makes things go bad, and I *think* that cooking it with soda or something is the cure. Don't quote me on that, though. The bottom line is that you can't just dig in and do it without getting the right info on how to process the rosin to make it inactive.

Raymond White's analysis at the National Gallery in London of Cremonese varnish indicated it was oil (linseed or walnut, depending on who, when) and something like rosin, so obviously they knew how to get it right.

Melvin Goldsmith--melving on Maestronet--uses a variation of it--I'm sure he'll offer some tips if asked.

[Andres Sender]

Hi Michael,

I can't remember--was the crazing a result of recipes using cooked pine sap/rosin?

The Forrester recipe from the '80s is a simple cooked pin sap/oil, and apparently some makers have been using it since then. I like the idea of using a simple pine sap/oil varnish along the lines of historical recipes, but I am concerned about stories about various failures or extreme color changes.

I made some of Bob Lundberg's oil/rosin varnish about 12 years ago, I have samples of it sitting around which have darkened to a bronzy-gold color due to iron content but otherwise so far so good.

Oded gave his recipe for a variation on the Keith Hill varnish over at Maestronet, which is an approach to coping with the acidity issue.

In my recent searches for other issues I found reference in one varnish discussion that acidity can be controlled by cooking, but no details on how that works. Joe Robson mentioned at Maestronet that lime is often used for this purpose.

[Michael Darnton]

Lime--that's what I was thinking of.

Yes, the defects show up with a cooked varnish. Maybe the amount of cooking is part of the problem. I wish I had paid more attention to the details of this, but I just wasn't interested at the time. I do know it's possible to make a good rosin varnish IF you do it right, though.

[Geemac]

If acidity is the problem then testing with litmus paper will show it. Acid may be neutralized with a base. I'll talk to a chemist or pharmacist about this and get a recommendation for what to use to handle the problem. Maybe just a pinch of lye will do it. We'll see. Great discussion folks. I have an old camp stove I can take into the back yard to try this out. Then if something catches fire I'll be able to put it out with no damage to the house.
_________________
GeeMac

[M.Lange]

I' not a chemist, but I think the pH-value is only defined for protic solvents and I'm not sure if litmus paper will work in a mixture of resin and oil.

Michael, could it be possible, that adding mastic will prevent an oil/rosin varnish from crazing?

Matthias

[MANFIO]

There is a varnish recipe that is known as the "Marciana" varnish, from a manuscript dated 1550, circa, in Venice. It's 2 parts oil, one part mastic, one part colophony, cooked. I use it to make a ground I like.

I've heard that Kremer's colophonies are already "treated" they mention their dark type as good type for making varnish, it will make quite a dark varnish.
_________________
www.manfio.com

http://www.flickr.com/photos/7875988@N02/with/464604020/

[Andres Sender]

Geemac--it is very very dangerous to cook varnish over an open flame. Much safer to do it on a lab hot plate. Aside from igniting the oil itself, many recipes result in a heavier-than-air vapor which is also flammable.

Even if you have a fire extinguisher handy it isn't going to help you if the varnish explodes and you get some on you which is at 200-300 centigrade.

As to litmus paper, Mathias is right, it doesn't work in varnish, it is intended for aqueous solutions.

Manfio--yes, that recipe is much on my mind of late, as it seems very compatible with what is known about Cremonese varnish.