Making a double bass

[Roger Hargrave]

The method of applying the ground coat with varnish mixed in it as a binder, uses  colored varnish, so more than one source of color.

 

 

 

 

Yes, You are right. I thought that I had made this clear. After the initial urine based treatment and the sunning, the ground varnish is applied. Although it has no added color this ground varnish has had color cooked into it. It is the same as the varnish that I use for the final coat. This also has no added colour.

 

As for Johns comments, I am not sure if you are saying that you do not remove the heat from the plaster before you mix it with the alcohol and water. If so I would guess that when it is in the wood it will harden. Am I correct in assuming that?  

 

I should add, as I said in the discussion about madders. I am not a great advocate of adding colors. Mixing them, that is mixing reds with yellows to make oranges and possibly even adding black, is a total disaster. Mixing always makes colors muddy and opaque. Blending, that is taking different batches of the 'same' color to create a specific shade of that color, is a better option. However colour blending is a highly skilled profession. Moreover it presupposes that you already have or can make something approaching the color that you require. Quite honestly the colors that most of us are chasing have almost certainly been altered by time anyway. I believe that in this respect our possibilities are very limited. 

[dan_s]

I use a plaster of paris sealer-filler.  A very easy method is to mix the water 50-50 with alcohol.  It will sit in a cup indefinitely without hardening.  I plan to experiment eventually to see if less alcohol is better.  Sugar will also work,  and could be the source of any sugars found with spectroscopy.  Because PP is so fine,  I don't see an advantage to adding coarser minerals.

The alcohol-water plaster is painted on.  When dry, much of the excess will drop off the surface.  But find a place your wife will not object to,  like outside,  and use a rag (Bounty paper towel is good) to wipe off the excess down to the surface.  It will look just like the talc covered double bass.  Silicates don't seem necessary with my methods.  But no reason not to experiment.

How you handle the varnish angle is up to you.  For me,  I would use a viscous material rubbed on with a finger.  The refractive index,  as Roger says,  will handle any sense of the result being opaque.  I have used such plaster as a filler.  With one special varnish application,  it is completely impervioius to a drop of mineral spirit put on the surface.

 

SILICATES:

 

I have made silicates both colored and uncolored.  One can cut ordinary K-silicate from Cramer to half strength.  This is just for convenience,  it lowers the viscosity to something close to water.  One can put alizarin (both red or yellow) in the solution and then add various metal salts.  For simplicity,  I use technical grade reagents which are cheap from GFS chemicals.  Tell them you are a violin maker and not a terrorist.  I have dealt with them for a long time so they at least know of one violin maker.

One can experiment with various salts.  Zinc will make a deeper color,  iron nicely darkens colors.  Epson Salt is magnesium sulfate available at any pharmacy.  Calcium cloride is available as salt melter in an auto store...... if you live in a cold climate.  Those are the common light-metal salts.   I dilute them to 5% by weight,  ignoring molecular weights.  It is close enough.

 

The silicates can be washed and filtered with coffee filters and used in differnet ways. 

 

 

Great stuff ! Worth a new thread.

[Michael_Molnar]

Here is my experience with intrinsically colored varnish. One day I noticed that the Canada Balsam from Kremer did not look like the CB I had on hand from military surplus stores when stockpiles of strategic goods were made during the 1940’s and 50’s. Lens makers use CB for cementing compound lenses, which eliminates surface reflections (ghosts) by the principle of index matching. The CB I had was a mixture of brilliant gold, orange and red, not the very pale yellow of Kremer’s CB. My epiphany was that my old CB had oxidized: Surely oxidized resins could make a colored varnish without adding pigments or dyes.

 

 

I tested oxidizing CB in a small inexpensive toaster oven. As Roger astutely noted and warned, the vapors are explosive. After a fire, I learned to melt the CB at the lowest temperature possible, and then raise the temperature to where the CB just starts simmering (very small bubbles). Then, I let this simmer gently for several hours in the open air. The result is a fantastic CB with great optical dichromatism (erroneously called dichroism). I stopped at that point because I lost interest in making varnishes (and fires).

 

Mike

[Johnmasters]

Great stuff ! Worth a new thread.

Then would you please erase your posting.  I agree it does not fit in.

[Urban Luthier]

Roger Hargrave, on 19 May 2013 - 06:43 AM, said:

... White had concluded that the colophony had not been cooked at a high temperature. He suggested that it had probably been heated just hot enough and long enough to blend it with the oil and mastic. (His conclusion about the mastic was that it had probably been added as plasticizer.)

In addition to this important observation about the cooking process, at a later date Professor White was asked to examine a particularly red and rather typical Venetian varnish on a violin by Sanctus Seraphin. White was specifically asked to identify the colouring agent. His reply was illuminating. Having examined the instrument he concluded that the redness in the varnish was simply the result of oxidisation, rather that any additional colouring agent. For me personally this was a revelation.

Roger,

I apologize if this is daft question but if there is a possibility (as Professor White suggested) the red colour is a result of oxidization rather than cooking the resins, what did the original varnish look like? Was it intended to be pale/colourless? In other words is the lovely red colour we see today primarily a result of the natural aging/oxidization process? Or is there a possibility the varnish was intentionally oxidized at the time of production by other means to achive the colour? (fiddlecollector alludes to the possibility in #246 with nitric) or does cooking the resin simply oxidize the resin itself? also Mike's post above #278)

Thanks,

Chris

[NewNewbie]

Roger,

I apologize if this is daft question but .... what did the original varnish look like?

Thanks,

Chris

Listen I know Roger has his Masters Makers certification because he is "old" but he isn't that "old"!

[Roger Hargrave]

Roger,

I apologize if this is daft question but if there is a possibility (as Professor White suggested) the red colour is a result of oxidization rather than cooking the resins, what did the original varnish look like? Was it intended to be pale/colourless? In other words is the lovely red colour we see today primarily a result of the natural aging/oxidization process? Or is there a possibility the varnish was intentionally oxidized at the time of production by other means to achive the colour? (fiddlecollector alludes to the possibility in #246 with nitric) or does cooking the resin simply oxidize the resin itself? also Mike's post above #278)

Thanks,

Chris

 

 

In spite of being not that old, I will attempt to answer this one. There are a several possibilities. The most obvious is that (especially in the early days) no colors were added; in which case these instruments would have been coated with a fairly transparent clear varnish, and why not. The early painted instruments may have had a thin transparent red glaze painted over them to enhance their motifs. This was standard practice for painters. However, this glaze cannot have been intense; otherwise it would have hidden the paintwork.

Next is the possibility that colors were added to the varnish, but that they have since faded. Not uncommon today, even after a few years; ‘Dragons Blood’ being one of the best examples. Then it depends upon what kind of varnish was used and how it oxidized. Venetians makers may well have used walnut oils and some other kind of resin. One that not only turned red with time, but also crackled in the way we often see it on Venetian cellos, (a feature of walnut oil). The so called classical period of violin making was more than 200 years old by the time these varnishes started to disappear. Over this period changes must have occurred.  Moreover, variations of these varnishes were probably in use a long time before violins arrived on the scene. Long before the 16^th c. musical instrument making in Europe was already an ancient craft. This ancient tradition might also mean that the later violin makers were already seeing oxidized red instruments. Nevertheless, the reason for introducing red into violin varnishes is more likely to have been the importance that the color red held. Red colors were precious and difficult to make. Red was worn and displayed almost like gold as a sign of status and wealth. 

[Urban Luthier]

My goodness! Although I'm likely one of the younger members who participates in the Pegbox, my questions were not meant to be ageist! (However NewNewbie's comment was quite witty!)

 

Seriously though Roger your commentary is illuminating. What I find fascinating about this dialog is the conflict between developing an historically authentic varnish recipie and creating an authentic looking varnish based on what we see today. 

 

The pictures are wonderful -- any chance you can post an image of the front of the viola during the varnishing stage in #263?

 

Thanks

 

Chris

[NewNewbie]

My goodness! Although I'm likely one of the younger members who participates in the Pegbox, my questions were not meant to be agist! (However NewNewbie's comment was quite witty!)

 

Thanks

 

Chris

"agist [əˈdʒɪst]vb (tr) Law

1. (Law) to care for and feed (cattle or horses) for payment

 

So are you calling Roger a horse?  :o And if so, what part???

Just messin' wit ya.

 

You bring up a good point, and that is what we are copying is in some ways more difficult to do, than to have copied the original.

If they only sold 'Artificial Aging' in a spray can we would have it made.

[Michael Appleman]

Roger, I've never known anyone in the violin world so knowledgeable and so generous with sharing your knowledge and experience.

 

A salient point I get from your posts is that you've noticed a marked improvement and consistency in the sound and playability of your instruments since you started using fillers/extenders in your grounds, but that you haven't noticed much of a difference whether you used silicates or plaster of paris. By silicates, I imagine you've tried different combinations of pumice, tripoli, rottenstone, pozzuolana...probably dozens of other things I've never heard of? I'm curious to know what you've experimented with.

 

My reading of the different articles on particluate grounds over the years led me to think tripoli was a leading candidate, and after trying out David Rubio's secret formula on one violin, I've been following Greg Alf's recipe of tripoli in varnish for my last few fiddles and am very happy with the results, tonally and visually. Being an amateur maker, working out of a cramped apartment in a big city, and not having enough time to finish more than one violin a year (at best), I'm afraid I'll never get to do varnish and ground experiments in any meaningful way. Information shared by you and experienced high quality makers such as yourself is so edifying!

 

BTW, after the last violin I varnished, I didn't carefully clean the ceramic mortar I used to mix my ground. The tripoli/oil varnish residue in the bottom hardened to stone, and nothing can get it off, it seems harder than the ceramic bowl itself. 

[Urban Luthier]

 

"agist [əˈdʒɪst]vb (tr) Law

1. (Law) to care for and feed (cattle or horses) for payment

 

So are you calling Roger a horse?  :o And if so, what part???

Just messin' wit ya.

 

You bring up a good point, and that is what we are copying is in some ways more difficult to do, than to have copied the original.

If they only sold 'Artificial Aging' in a spray can we would have it made.

 

an embarrassing typo on my part I'm afraid! my apologies 

 

Chris 

[Urban Luthier]

 

...My reading of the different articles on particluate grounds over the years led me to think tripoli was a leading candidate, and after trying out David Rubio's secret formula on one violin, I've been following Greg Alf's recipe of tripoli in varnish for my last few fiddles and am very happy with the results, tonally and visually. Being an amateur maker, working out of a cramped apartment in a big city, and not having enough time to finish more than one violin a year (at best), I'm afraid I'll never get to do varnish and ground experiments in any meaningful way. Information shared by you and experienced high quality makers such as yourself is so edifying!

 

I'm in the same boat as you Oringo! I use tripoli as a ground as well. The challenge I have is that mixing the tripoli into the varnish to make the ground uses up quite a bit of varnish itself. As result one needs more varnish on hand to get the job done. OK if you are skilled at making your own, not so good if you are relying on commercial products

[robertdo]

I'm in the same boat as you Oringo! I use tripoli as a ground as well. The challenge I have is that mixing the tripoli into the varnish to make the ground uses up quite a bit of varnish itself. As result one needs more varnish on hand to get the job done. OK if you are skilled at making your own, not so good if you are relying on commercial products

I tried a slightly different approach on scrap of maple and spruce, but rather than mixing varnish and tripoli, I rubbed the wood with some tripoli and took away as much as possible with a rag I suppose it's similar to Paris plaster described by R. Hargrave). I then

applied some varnish. It seems to be ok if using some tripoli or some other mineral is your goal.

[Roger Hargrave]

I tried a slightly different approach on scrap of maple and spruce, but rather than mixing varnish and tripoli, I rubbed the wood with some tripoli and took away as much as possible with a rag I suppose it's similar to Paris plaster described by R. Hargrave). I then

applied some varnish. It seems to be ok if using some tripoli or some other mineral is your goal.

 

Tripoli works well with water, as do several other similar fillers. I like it, but it is not always the same, there are several varieties of tripoli. Mixing any filler/extender directly with the varnish is usually more wasteful, but as I said at the beginning there are as many fillers as there are violin makers. You just need to try them with your own varnish.

[Oded Kishony]

Tripoli works well with water, as do several other similar fillers. I like it, but it is not always the same, there are several varieties of tripoli. Mixing any filler/extender directly with the varnish is usually more wasteful, but as I said at the beginning there are as many fillers as there are violin makers. You just need to try them with your own varnish.

 

Any fillers you would definitely NOT use?

 

(sorry if this has been already covered)

 

I would list any with a strong chemical profile, strong base, such as potash etc.

 

OK

[Brian Lisus Violins]

Tripoli works well with water, as do several other similar fillers. I like it, but it is not always the same, there are several varieties of tripoli. Mixing any filler/extender directly with the varnish is usually more wasteful, but as I said at the beginning there are as many fillers as there are violin makers. You just need to try them with your own varnish.

Hi Roger,

Many thanks, great post and photos!

 

I have used Marienglas from Kremer as a filler for many years now and wonder if you have any experience with it? It is super fine and becomes really transparent when the varnish is applied over it.

 

I have aslo been using walnut oil for about six years and you mention that it can crackle with age ... so far it has worn really well with no signs of that all, do you think this might still occur? I do wash and sun thicken it before hand though. 

Look forward to seeing photos of the finished bass.

Cheers,

Brian

[Guest]

Hi Brian

I've been using the Marienglas too after reading your contributions on MN awhile back. I find it to be very transparent as well. I was thinking of trying this filler next...

http://www.kremerpigments.com/shopus/index.php?cat=010504〈=ENG&product=58950

 

[Johnmasters]

As for Johns comments, I am not sure if you are saying that you do not remove the heat from the plaster before you mix it with the alcohol and water. If so I would guess that when it is in the wood it will harden. Am I correct in assuming that?  

 

Actually,  I spoke before I had read all of your postings.  This was a simple way to get enough plaster of paris  into the wood in order to use capillary action to hold further oils out of the wood.  I have not felt that any heat from the reaction is an issue.

 

The alcohol prevents a full reaction.  But the wiped surface has obviously been impregnated with a dense semi-stable plaster of paris.  The PP remains workable until the fluids evaporate.

 

This seems non-Cremona formula,  it seems a bit involved.  but it is possible to dye the water/alcohol.

 

An interesting experiment is to make the fluid have 1/2-1% of pyrogallo.  Pyrogallic acid.  This is closely related to tannic acid.  Tannins from oak galls likely would work also.

 

After wiping the surface,  I wipe or shoot (I like to spray) .25% ferric chloride.  Perhaps ferrous salts would also work.  I just happen to use the ferric salt as it does not react with oxygen (and tries to go to the ferric form).  After that,  a .25% dichromate solution.  There is plenty of water here to completely hydrate the PP,  and also brings out a dark surface. 

 

Finally,  3% hydrogen peroxide,  perhaps two applications,  will drastically bleach the pulp wood and one is left with a very nice annual grains dyed brown.

 

The idea came from this:  The plaster is a blanket of high capillarity.  It occurred to me that it would release more pyrogallo into the dense annual rings than into the pulp.  This seems to be the case.  I found the idea in discussions of ground water being pulled up through various soils.

 

One can add small tints of red,  and the rings can be dyed dark red.  The pulp will retain some pink,  but it is not an issue.    .1% or so a strong dye seems sufficient.

 

Does this allow minerals and varnish to be mixed?  It does not.  But it prepairs a nicely stained surface that some may like to try.

 

I also use a paste-type sealer which I can discuss if it is wanted..... I know it is not in the logic of your postings.

[Bill Yacey]

I have this vision of someone holding a rabbit up while someone else holds a jar under it waiting for the rabbit to pee.  I think I'll just stick with Roger's plaster of Paris.

To speed up the process, give the rabbits beer to drink. Perhaps the urine of a beer drinking rabbit is more potent.

[Bill Yacey]

 

After wiping the surface,  I wipe or shoot (I like to spray) .25% ferric cloride.  Perhaps ferrous salts would also work.  I just happen to use the ferric salt as it does not react with oxygen (and tries to go to the ferric form).  After that,  a .25% dichromate solution.  There is plenty of water here to completely hydrate the PP,  and also brings out a dark surface. 

 

Does the ferric chloride get netralized at some point? It's extremely caustic and I would be concerned about long term breakdown of the wood.

[Johnmasters]

Great stuff ! Worth a new thread.

Thanks very much.... I would like to share these ideas.  They have some merit and may be of use to some people.  I have no need for secrets.  (My sons have no interest !!)

[actonern]

Circling back to the question of how to put color in the varnishes...

 

I've found that varnishes made from extended cooked down resins tend to be more fugitive than what you get with particulates...

 

Any thoughts?

 

E

[DarylG]

I've found that varnishes made from extended cooked down resins tend to be more fugitive than what you get with particulates...

 

By particulates do you mean pigments?

[actonern]

Sorry, yes, Daryl, I meant pigments, madder lakes... anything that started as a powder before going into the sauce...

 

E

[Adam Edwards]

Circling back to the question of how to put color in the varnishes...

 

I've found that varnishes made from extended cooked down resins tend to be more fugitive than what you get with particulates...

 

Any thoughts?

 

E

 

Circling back to the question of how to put color in the varnishes...

 

I've found that varnishes made from extended cooked down resins tend to be more fugitive than what you get with particulates...

 

Any thoughts?

 

E

Yes