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Synthetic rosin


Woodland

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I recently tried to remove some heavy rosin buildup from bow hair with alcohol, to no avail. I proceeded to do a full rehair instead after several attempts failed to remove the residue. The customer informed me that she uses the hypo-allergenic rosin. What's in that stuff?

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This seems to be the patent for the "Clarity" rosin. I have cut and pasted excerpts from it. The exact chemical compound is not identified so determining the liquid that it is soluble in (thus cleaning the hair) is not possible. Methyl alcohol (methanol), ethanol, acetone and benzene are common solvents for organic compounds. Others have suggested xylene. Acetone and especially benzene are quite hazardous to use.

Patent 6906138 - Thomas H. Quinn.

Rosin is primarily comprised of abietic acid, isomers of abietic acid, and numerous other naturally occurring compounds. Because it is naturally derived, and because of its organic acid chemical structure, rosin has at least five distinct drawbacks: 1. Rosin is hydrophilic and absorbs water. This causes the tackiness of the rosin to vary according to ambient humidity, which affects the sound of the instrument. 2. Rosin is susceptible to oxidation. Rosin becomes a fine powder, when applied to bow hairs. This powder has a high surface to volume ratio and rapidly reacts with ambient oxygen. As rosin oxidizes, it loses tack and essentially loses its effectiveness. 3. Rosin is a naturally occurring resin suspected of causing allergic reactions in susceptible people. 4. Rosin is primarily an organic acid and potentially corrosive. Rosin dust typically accumulates on the surface of the instrument and bow and can corrode the wood's varnish. 5. Rosin is very brittle and tends to break easily.

It is possible to slightly improve upon the properties of rosin and minimize some of these drawbacks by adding polymers to improve impact resistance, adding antioxidants to minimize oxidation, chemically reacting rosin by hydrogenation or esterification to minimize oxidation, and rosin can be neutralized with bases to minimize corrosion. However, none of these modifications, in whole or in combination, can significantly improve upon the properties of the bow rosin used today.

SUMMARY OF THE INVENTION

The present invention discloses that the use of synthetic hydrocarbon resins, and compounds thereof, that are substantial improvements over the properties of rosin while surprisingly producing musical tone at least as good as rosin.

For this invention, synthetic hydrocarbon resins are defined as resins resulting from controlled chemical reactions such as polyaddition or polycondensation between well-defined reactants, that do not themselves have the characteristic of resins. Bow resins are defined as synthetic hydrocarbon resins that are applied to bow hairs to cause friction on the strings of an instrument to produce sound.

Examples of synthetic hydrocarbon resins of the present invention include indene-coumarone resins, aromatic C9 resins, aliphatic C5 resins, C5/C9 blended resins, dicyclopentadiene resins, alpha-methylstyrene resins, and alpha-methylstyrene vinyl toluene resins, polyterpene resins, and hydrogenated versions of each of these.

These substances improve upon the properties of rosin in at least five ways: 1. They are hydrophobic. They resist the absorption of water and their tack is nearly unaffected by ambient humidity. This results in a more consistent sound from one moment of time over another regardless of humidity. 2. They are saturated hydrocarbon compounds that are resistant to oxidation. They are virtually non-reactive with ambient oxygen, even in a finely powdered form, and thus resist losing their tack or effectiveness over time. 3. They are synthetic materials significantly less prone to being allergenic than rosin. 4. They are chemically inert with regard to instrument varnishes and do not corrode the varnishes. 5. The addition of small amounts of selected polymers decreases brittleness making these compounds less prone to breakage. Example 1

Example 1

99.9 grams of hydrogenated DCPD resin (Escorez 5380), with a R&B Softening Point of 80C, was combined with 0.1 grams of hindered phenol antioxidant (Irganox 1010) and melted at 150C. The mixture was blended until smooth, and poured into a silicone mold and cooled to form a cake about 3 cm in diameter and 1 cm thick. When applied to a bow, the bow resin in Example 1 resulted in a clear musical tone. Over repeated uses there was minimal buildup of resin dust on the instrument or bow hairs. Use under humid ambient conditions resulted in no perceptible change in resin tack or musical tone.

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The theory is great.

In practice I've found Clarity to be too soft, too messy (mounds of rosin dust), too hydroscopic, too prone to stick to varnish, too hard too remove without damaging the varnish. It seems to be easily removed (before solidification on the violin) with xylene, and is easily washed off bow hair with ethanol.

What am I to make of this?

The claims in the patent for Clarity in my experience apply much better to Geipel rosin.

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It was my guess that the patent described Clarity as an ad for Clarity had exactly the same negatives for regular rosin and the same 5 points of advantages for the synthetic Clarity rosin. Maybe one or the other company copied the description. I don't know. But patents are legal documents that sometimes claim everything and are not very realistic with those claims.

Woodland - maybe trying a different alcohol - ethanol instead of methanol or vice versa - would do it. An obvious word of caution - some of the alcohols, as well as xylene and acetone are not very finish friendly.

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"...some of the alcohols, as well as xylene and acetone are not very finish friendly."

Yes, don't go anywhere near varnish with acetone, and xylene only if you really know how to use it, and on what you are using it.

Regarding the hypo-allergenic properties of Clarity: at least I can vouch for that. A violin teacher customer of mine who was considering a career change after two episodes in ICU could actually continue in her vocation after she - and ALL of her students - switched to Clarity.

Geipel is half the price, and I think it is a better rosin - not as messy and soft. In fact, it is practically dust-free.

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Excellent post, davet. I didn't know there was so much info available about Clarity rosin. It's a shame I'm not a chemist so I could understand all the stuff about hydrocarbons and such. There's probably a clue in there somewhere that would explain why I had so much trouble with the stuff.

I had a very bad experience with Clarity but it was mostly my fault. I was just learning how to play and was trying to find the best rosin/application to use in various weather situations. I had heard about Clarity being non-hydroscopic so I thought it might give me better performance in severe humidity situations. Here in Florida, the bow can be subjected to the dryness of airconditioning and the wetness of a riverside jam in the time span of a single afternoon.

I had been experimenting with several different rosin types so the hair was already fully loaded with natural stuff when I started applying the Clarity. The first few applications were inconclusive so I kept applying and playing it in. By the time I recognized I was headed to disaster, I had already loaded up the bow and found I had no way of removing the stuff.

The problem manefested itself as tiny plastic beads of synthetic rosin bonded to the strings in the bowing zone. These effected the sound and made it very hard to keep bowing consistently. Alcohol wouldn't touch the stuff. Nothing I tried would remove it other than using one's fingernail and carefully scraping the stuff off. Afterwards, I'd have about five minutes of clear playing before the beads would build up again and the sound would turn bad.

I stopped using the Clarity after I washed the cake in acetone and it didn't dissolve. I didn't know what it was, I just knew I didn't want it on my fiddle anymore. I tried washing the bowhair in alcohol but that only removed the organic rosins. Since it was the only stuff that didn't wash off, I tried using the bow with just the Clarity, thinking the combination of natural vs. synthetic was the problem but that didn't work. I wanted to get the bow rehaired but as luck would have it, my local violin shop was between bow repairmen.

I ended up 'playing-off' the Clarity a little at a time over a period of about six months. I had two fiddles at the time but only one decent bow, so I'd pick one up and play until the buildup occured then I'd switch to the other fiddle. After both were loaded with plastic beads stuck to the strings, I'd stop and scrape them off, clean up and start playing again. The buildup slowed by degrees and finally stopped.

I'm a Hill Dark man now.

And I have a new bow.

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A lightbulb came on after my above replies which was why not email the rosin manufacturer and get their recommendation for their rosin removal from bow hair. So I wrote Super Sensitive Co (Clarity rosin) and got the following reply.

"We do not recommend using any cleaner on the bow hair. Use a soft toothbrush and gently brush the hair until clean.

Hope this helps!

Sincerely,

Mary Nell Chadsey"

I couldn't find the web site for Geipel which is supposedly made in Germany by the Geipel Company. Woodland didn't specify which rosin his customer was using.

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As the inventor of Clarity maybe I can answer some questions. Both rosin and Clarity are hydrocarbons, but they have different chemical reactivity and solubility. Rosin is mostly composed of a cyclic organic acid which is reactive and an allergen. The acid functionality of rosin makes it soluble in alcohol. Clarity is a saturated hydrocarbon (like mineral oil and wax) and has essentially no reactive groups at all. It has no polarity and is insoluble in polar solvents like alcohol and acetone. However, it is very soluble in mineral spirits, which by the way is a more gentle solvent for violin finish than alcohol. Mineral spirits is also a good solvent for rosin. Just remember that mineral spirits is less volatile than alcohol and will take longer to dry.

Microfiber cloths work the best for cleaning anything on a violin from my experience.

The comments from Jacob are puzzling. Clarity is very hydrophobic and being essentially dust free, I've never seen it form "mounds". Whether too soft or not is a matter of preference. It's possible to make Clarity from one extreme of hardness to another and I know the particular balance of properties Supersensitive settled on is based on user studies they did. Personally, I'd make it in about 5 grades from soft to hard and let people choose the one that works the best for them. Kind of like x-country ski wax.

Geipel rosin, like every other rosin is primarily composed of abietic acid, and as such is no more hypoallergenic than any other rosin. The FDA is lax on specifying what "hypoallergenic" means and I'd be very interested in seeing what data Geipel has to support what I suspect is largely a marketing claim. On the other hand, the components of Clarity have been used as the primary components of surgical tape adhesives and baby diaper adhesives for 25 years. They are very benign materials.

Let me know if you have any more questions.

Regards,

Tom Quinn

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Hello, Tom.  Great to have you on this thread!

I must admit that I never tried Clarity, because I was afraid of

what it might mean to inhale hydrocarbon dust. (It may be low-dust,

but it can't be COMPLETELY dust free, can it?)

Of course, as you say, organic resin is also a hydrocarbon.

 When I first started studying the violin (only a few years

ago) I was very worried about inhaling the dust, and posted a query

about this on another forums.  Some folks dismissed it as

silly  (fools)  while a few intelligent individuals

thought it was a darned good question.  Unfortunately, even

though some of these enlightened ones work in the medical fields,

non could find any hard data on the subject.

I don't suppose you have any data on the health issues, do you?

 (such studies would be very hard to do, and likely be

incidental at best.)

Perhaps one could consider clarity safer, if it has less dust.

 Hmmm..

-But I also need a soft rosin, as I use natural-gut strings.

 As you say, they should make various grades of the stuff.

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Bizarre thought:  (as if my last post weren't enough)

I wonder what kind of varnish could be made by heating up some

Clarity & a little Madder Lake, or whatever. Would the

properties that make it (supposedly) a better rosin also make for a

"better" oil varnish?

-Or could Clarity even experiment with new formulas specifically

for oil varnish.  There's probably a good market there, once

all the luddites die off. ()

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Excellent post Tom! I never thought to try mineral spirits... Stuck in a rosin mindset I guess. When acetone failed to even touch the stuff, I kinda freaked. Now I know so next time won't be so scary.

I still have my cake of Clarity. It's quarrantined in a little drawer somewhere in my workshop. Someday I might get the idea of trying it again. I think the trick is to start with clean hair. Wash all the traditional rosin out before applying any Clarity. Friends of mine use it without any problems so it should be do-able. I like the possiblilty that it might be more stable in humid environments. Plus I do have a slight reaction to regular rosin when my allergies are flaring up.

Again, thanks for answering some questions I've had for a long time!

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Hi Tom,

Thanks so much for your response, it is very much appreciated.

I don' really know what to say about my experience with dust etc - perhaps it can be blamed on the climate here?

Your comments about Geipel are also interesting. Geipel offers a "normal" as well as a hypo-allergenic rosin. I guess from a practical point of view I can only report the reaction to the hypo-allergenic rosin by customers of mine with a very severe allergic reaction to natural colophony.

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quote:


Originally posted by:
Allan Speers
Hello, Tom.

 . . . . But I also need a soft rosin, as I use natural-gut

strings.  As you say, they should make various grades of the

stuff.

You could try the Clarity cello rosin (softer than violin/viola) or

Clarity Summer bass rosin (softer yet) or Clarity Winter bass rosin

(even softer.) The softer rosin also seems to dust even less, or at

least in larger particles, which fall out of the air more quickly.

I sell Clarity in my shop for about $12, you could probably find it

locally for about the same. Or online for $8.95 plus $4

shipping.

Onree

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  • 11 years later...
  • 2 years later...

Hi, 

I know this is a very old topic, but I have a solution (excuse the pun!) for cleaning Clarity rosin off strings and bodies - Servisol Super 10 switch cleaner; available from any electronics shop.
Obviously I’d recommend a patch test before use, but I’ve been using Servisol to clean off Clarity for over 10 years and never had an issue with varnish.
I’ve even used it to clean bow hair, though make sure your bow hair has plenty of time to dry off after cleaning or you will end up with a very sticky mess! 

I hope that’s of some help,

cheers,

Daf
 

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