Colophony Recipe

[Shunyata]

 

I am planning a first shot attempt at colophon varnish.  Does this seem like a reasonable recipe? (from Peter Grankulla web page) Colophony 140g, cooked down to 75g Boiled linseed oil 75g Gum mastic 15g Turpentine 45g Colophony cooked for 15+ hours at 150 - 180 C The temperature is gradually raised to keep the same viscosity Weight reduction 46.5% Lots of stirring!! especially in the first hour when it fumes a lot  Linseed oil heated to the same temperature and slowly stirred into the colophony Cooked for 50 min together with the colophony Reducing temperature to ~100 C Mastic drops added slowly while stirring Cooked for another 15 min at lower temperature to 90 - 100 C  until the varnish is very calm   Balsam turpentine heated to simmer Slowly stirred into the varnish and cooked 5 - 10 min until calm again Filtered and decanted into a glass jar.

[Jim Bress]

I use Roger Hargrave’s recipe from “Making a double bass”

https://www.roger-hargrave.de/Seiten/english/Bibliothek/Bibliothek.htm

[Shunyata]

Jim... do you extend cooking time for color or do you add colorants?

[Jim Bress]

You cook for color separately from making the varnish. Reducing the weight by ~80%. You need approximately twice the cooked colophony as you have in the varnish. Remelt the cooked colophony and add 1:1 LO by weight then add to varnish. 
 

I cook the colophony for color first. Then do everything else the same time. 

Edited August 3, 2022 by Jim Bress
Replaced volume with weight

[Peter K-G]

Hi Shunyata,

The recipe is practically a close variant of Roger Hargrave's description from his Making a double bass book.

I think it's better to measure weight reduction than volume, when you cook the Colophony for color. The reduction and desired color can only be achieved by testing for the particular colophony you use.

It's important to get the linseed oil up to temperature before mixing (as also Roger wrote) so that you get the chemical bond between colophony and oil. Otherwise some of the oil will not be bond to varnish.

I'm on my third batch this summer with even more reduction (50%) and it's even darker and more red as I have cooked the colophony as slow/low temperature as possible.

 

Good luck

 

[Jim Bress]

Yup, weight not volume. 

[David Stiles]

I used a very similar recipe with good results.   Only difference with my recipe was that it had about 3g of Calcium Hydroxide to the colophony.

For some reason, after 20 hours cooking my colophony only reduced in weight be about 25%

[joerobson]

13 hours ago, David Stiles said:

I used a very similar recipe with good results.   Only difference with my recipe was that it had about 3g of Calcium Hydroxide to the colophony.

For some reason, after 20 hours cooking my colophony only reduced in weight be about 25%

The colophony you started with may be a different grade.

[Mille regardz]

21 hours ago, Jim Bress said:

You cook for color separately from making the varnish. Reducing the weight by ~80%. You need approximately twice the cooked colophony as you have in the varnish. Remelt the cooked colophony and add 1:1 LO by weight then add to varnish. 
 

I cook the colophony for color first. Then do everything else the same time. 

I am not sure if I understand you correctly.

Do you mean that if you make a varnish using 100g colophony and 100g linseed oil, you would add another 200g of cooked colophony for color (obtained from 1kg uncooked colophony) and 200g linseed oil? That sounds like a lot!

Or would you add 40g of cooked colophony (obtained from 200g uncooked colophony) and 40g linseed oil?

[Jim Bress]

20 minutes ago, Joris said:

I am not sure if I understand you correctly.

Do you mean that if you make a varnish using 100g colophony and 100g linseed oil, you would add another 200g of cooked colophony for color (obtained from 1kg uncooked colophony) and 200g linseed oil? That sounds like a lot!

Or would you add 40g of cooked colophony (obtained from 200g uncooked colophony) and 40g linseed oil?

Use the weights of cooked colophony. You can scale the recipe up or down by proportion to make the amount of varnish you want. 

[JacksonMaberry]

Jim Bress' Hargrave style varnish is good. Find the discussion in the "bass blog" for the how's and why's. 

Peters varnish looks very nice too and is one of the darker plain colophony varnishes I've seen. 

Adding calcium hydroxide gives you a calcium rosinate varnish, not a colophony varnish per se. There are both benefits and drawbacks to this type of varnish. 

Of the natural resin varnishes I personally prefer larch to pine. Strasbourg is even better, but no longer commercially available. 

For a redder hue, use some sandarac. It needs to be fused, like a fossil resin, before it will play nice with oil. Take it slowly up to 300C and hold it there a while to accomplish this.

[Evan Smith]

41 minutes ago, JacksonMaberry said:

Adding calcium hydroxide gives you a calcium rosinate varnish, not a colophony varnish per se. There are both benefits and drawbacks to this type of varnish. 

 

I have read that colophony has long been considered the cheapest of varnishes.

That in itself doesn't mean a lot, I am not going to varnish a boat, or a bowling alley with it.

Do you mean that by making a rosinate out of it,, the characteristics change to the point that it is no longer in the same category,, of such?

Is zinc oxide better?

Should I dissolve the colophony in lye and then add the zinc,, I really don't know much about these things, I just throw it in a pot and cook, it seems to get something that will work,, probably by a stroke of luck, which is better than a strike of lightening.

I know this has been discussed AD infinitum,,,

But I am paralyzed till I do it, where to start?

Made Fullton's varnishand others many times successfully, but no rosinates.

[JacksonMaberry]

12 minutes ago, Evan Smith said:

I have read that colophony has long been considered the cheapest of varnishes.

That in itself doesn't mean a lot, I am not going to varnish a boat, or a bowling alley with it.

Do you mean that by making a rosinate out of it,, the characteristics change to the point that it is no longer in the same category,, of such?

Is zinc oxide better?

Should I dissolve the colophony in lye and then add the zinc,, I really don't know much about these things, I just throw it in a pot and cook, it seems to get something that will work,, probably by a stroke of luck, which is better than a strike of lightening.

I know this has been discussed AD infinitum,,,

But I am paralyzed till I do it, where to start?

Made Fullton's varnishand others many times successfully, but no rosinates.

Hey Evan! Colophony varnish is often discussed as a cheap/bad varnish, but the studies have shown that's what great violins were slathered with and so why not? You're right on the money. If we were building sloops or ninepins lanes we could talk amber or congo. 

My comment on calcium rosinate was mostly just to point out that 1) by liming the rosin you're turning it into something else and 2) point out that a lot of people, whether they're anti-rosinate or just neutral, are in fact making and using rosinates whether they know/like it or not. That's just the truth of what it is scientifically. 

Zinc rosinates do, demonstrably, outperform calcium rosinates in every useful metric, most importantly they are not water soluble, whereas calcium rosinate is partially. However, liming (adding calcium hydroxide) rosin serves both to modify the resin and also to neutralize the acidity. Zinc hydroxide however is not equivalent to calcium hydroxide in basicity - calcium is an alkaline earth metal and has closer on the table and in performance to sodium and potassium than zinc, a transition metal, who's hydroxide is amphoteric rather than flatly basic.  If you want to use zinc, you'll have to use the liquid process rather than the fusion process. The liquid process always provides superior, cleaner results chemically anyway in part due to the ease of titration. 

To start, read my article in The Scroll. It takes Michaelman and makes it easier to follow, and does away entirely with cold-mixing varnish, which is better avoided for the most part. 

[Michael Szyper]

I consider Jackson’s paper in the Scroll to be one of the most useful instructions about varnish making I have read so far. He tells almost everything you need to know. Usually there is plenty of stuff written in order to make the author look smart but actually not telling anything. 

[JacksonMaberry]

1 hour ago, Michael Szyper said:

I consider Jackson’s paper in the Scroll to be one of the most useful instructions about varnish making I have read so far. He tells almost everything you need to know. Usually there is plenty of stuff written in order to make the author look smart but actually not telling anything. 

Wow, thank you Michael! That is a very kind review, and I appreciate it a lot. My goal is always to make things plain, and though I usually fall short I'm glad it worked that time. 

[Davide Sora]

3 hours ago, Michael Szyper said:

I consider Jackson’s paper in the Scroll to be one of the most useful instructions about varnish making I have read so far. He tells almost everything you need to know. Usually there is plenty of stuff written in order to make the author look smart but actually not telling anything. 

I agree, I have never put up with those who say things to show themselves, omitting to give the accurate details necessary to really understand things.

Definitely not the case with Jackson.

[Shunyata]

Where do people get Colophony?  I didn't see anything at International Violin.

[Michael_Molnar]

Try Woodfinishing Enterprises

 

[Urban Luthier]

+1. Read Roger's bass book. I'd like to make a few edits to the varnishing section that we left out when preparing the book

• As Jim notes above - to get the colour of Roger's varnish - you are looking a a cook that reduces the colophony by about 80%!
• For Roger's varnish recipe, all measurements are by weight 

[JacksonMaberry]

6 hours ago, Davide Sora said:

I agree, I have never put up with those who say things to show themselves, omitting to give the accurate details necessary to really understand things.

Definitely not the case with Jackson.

Wow, high praise, thank you Davide. 

[Evan Smith]

On 8/4/2022 at 1:23 PM, JacksonMaberry said:

 

 

 Zinc hydroxide however is not equivalent to calcium hydroxide in basicity - calcium is an alkaline earth metal and has closer on the table and in performance to sodium and potassium than zinc, a transition metal, who's hydroxide is amphoteric rather than flatly basic.  If you want to use zinc, you'll have to use the liquid process rather than the fusion process. The liquid process always provides superior, cleaner results chemically anyway in part due to the ease of titration. 

To start, read my article in The Scroll. It takes Michaelman and makes it easier to follow, and does away entirely with cold-mixing varnish, which is better avoided for the most part. 

Your article is most excellent!

Very Well written and clear, did you edit it also?

So my question is,,,,

Can I substitute and use zinc oxide, or do I need to precipitate the oxide in sodium hydroxide and use that,,

does it matter, I am a chemist by no means.

Evan : in the corner with dunce hat on.

[JacksonMaberry]

13 minutes ago, Evan Smith said:

Your article is most excellent!

Very Well written and clear, did you edit it also?

So my question is,,,,

Can I substitute and use zinc oxide, or do I need to precipitate the oxide in sodium hydroxide and use that,,

does it matter, I am a chemist by no means.

Evan : in the corner with dunce hat on.

@Jim Bressproofread it for me and helped me with citations, but The Scroll staff published it without edits. 

Im afraid you'd be better off purchasing some zinc sulfate monohydrate. It's very cheap. You're not going to want to prepare the sulfate from the oxide yourself.

[Michael Szyper]

17 hours ago, Shunyata said:

Where do people get Colophony?  I didn't see anything at International Violin.

I tried different kinds of resin so far. Cheapest industry colophony for 10€/kg, burgundy resin, larch turpentine, self collected spruce resin from northern Italy, Sandarac and a lot more.

so far I did not notice huge differences in the colophony range. The best results with the cheapest crap. So in my opinion there is no reason to be too picky about colophony.

Interestingly, The spruce resin colored quite fast but rather brownish. I assume it is due to the higher iron content, but that is just a pure claim with no proof.

I imagine that high acidity with low iron content makes the best colophony for cooking. No worries about the acids, colophony is loosing almost all its acidity whilst heavy cooking.

My colored resins loose 90% of weight. 80% is a little to light in color for me.

[Peter K-G]

18 hours ago, Urban Luthier said:

+1. Read Roger's bass book. I'd like to make a few edits to the varnishing section that we left out when preparing the book

• As Jim notes above - to get the colour of Roger's varnish - you are looking a a cook that reduces the colophony by about 80%!
• For Roger's varnish recipe, all measurements are by weight 

For the colophony It isn't so clear though; volume or weight?

"Having decided how much varnish I wish to make, I cook the resin low and slow. After quickly loosing various volatiles, it is gradually reduce in volume; up to and possibly more than 80%. "

[Peter K-G]

For the colophony I use, I don't think it would be possible to reduce it by 80% weight loss. 50% feels already on the edge.

It might have been reduced already at production stage, have to find out from the seller.