Double Bass How to revive old rosin using rubbing alcohol...

[csrund]

This is excerpted from a Facebook post by IU prof. Kurt Muroki:

Kurt Muroki best way to revive old pops or any other rosin for that matter is not with humidification... The best way is alcohol. Put a quarter size amount of alcohol-based hand sanitizer or 50/50 rubbing alcohol and water in the bottom of a small Tupperware container, put the rosin in a pops rosin container with the lid open, or any other method that does not allow the rosin to touch the alcohol. Leave overnight and your rosin will be soft. Leave it for 2 or 3 days and you can pour your rosin on your bow.
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Haven't tried it yet, but I've got a couple of powdery Pops cakes that are good candidates for the experiment. I'll post results.

 

[KUNGfuSHERIFF]

I have a roughly 40-year-old cake of Pops that came with my Mortone. I may have to put this to the test tonight...

 

[csrund]

Okay, I tried this overnight, and it works remarkably well! I rejuvenated a cake of Pops and a cake of Kolstein. I put them into sealed Tupperware canisters with the 50/50 solvent mix of rubbing alcohol and water and left them from midnight to 6:45am. The tops of each cake were dramatically softened—so much so that I wouldn't apply to bow hair in their current state. I'll leave them in open canisters for a while to harden a bit.

So be warned: Don't overdo it! I probably should've checked on the cakes after the first four hours. A couple of things I don't yet know:

1. How deep into the cakes the solvent penetrated and softened; and
2. How well it will work on the bow hair and strings
​

Please post your results here...

 

[jasonrp]

I'll know when I get home from work. I've got pops in Tupperware with a quarter sized pool of hand sanitizer. By the time I get home it will be just shy of 24 hrs

 

[KUNGfuSHERIFF]

Son. Of. A. Gun. It looks like it worked!

 

[jasonrp]

Same here, I wish I did a before and after shot. I had the same result as the OP in that my cake is way too soft to use at the moment so I'm gonna leave the cap open for awhile.

Thanks for the tip! I can't believe it worked. As little as I bow, I'd hate to replace it every time it dries out.

 

[gerry grable]

I accidentally discovered the effect of alcohol on rosin when I substituted 90 percent alcohol instead of water on my small square of sponge in my home made Ball canning jar humidifier for rosin. It got sticky and gooy so I threw it out. I didn't think to let it dry.

 

[John Chambliss]

Amazing!!!

 

[statsc]

Wow; this really works, and quickly (only took about an hour!). With the amount of bowing I do, I won't need to buy any rosin for the next 10 years!

 

[damonsmith]

Yeah, as with others I've found it works great and overnight is overkill. I am on tour and grabbed an old Pops by mistake. I had the 50/50 alcohol to clean my strings .

I followed the instructions and had soft as fresh Pops in a few hours.

Good find.

 

[KUNGfuSHERIFF]

The cake I experimented on is at least 30 years old so 24 hours was barely enough.

 

[jasonrp]

24 hrs was overkill... I left my top open all day and I could still leave a fingerprint on it with a gentle touch

 

[Chris Fitzgerald]

Great find! Will sticky this....no pun intended.

 

[jasonrp]

I'm no chemist but through years of private study I can confirm that alcohol always works better than water

 

[gerry grable]

I'm no chemist but through years of private study I can confirm that alcohol always works better than water

If you drink enough.

 

[s0707]

Any chemists who can explain why alcohol works better than water?

My guess is that alcohol is a solvent of rosin. When you put it in the container, it evaporates and a bit of the alcohol vapor gets absorbed by the rosin.

Another guess of mine would be that other solvents like thinner, mineral spirits, etc. might work too, but you may need to dilute them even more since they're probably stronger than alcohol. Alcohol seems a safer alternative.

 

[Fasha]

Living in Canada I have had my rosin frozen and melted, but at room temperature it seems still to retain its qualities - or am I fooling myself?

 

[s0707]

I think you're on the right track. The little bit of research I've done says that rosin is similar to turpentine and so it's soluble in alcohol and not water. If that's true why the 50~50 mix? I`m no chemist but I see chemical equations in my future and I suspect that the water is either a red herring or an intentional slower of the reaction.

I think 50/50 is an appropriate dilution ratio.

I would think it may be possible to put 100% alcohol in the container, but just the same amount as you'd use in the 50/50 ratio. My guess is that the rosin is not absorbing the water from the vapors, only the alcohol.

I'm a beginner at double bass and my cake of pops rosin is still fresh, so I haven't tried the experiment, but I'll sure keep this great tip in mind for when the time comes to revive it. Thanks for sharing!

 

[Andy Mopley]

50% nail polish remover (don't ask..) + 50% water - softening on Pops and old Neyman (purple container) within 1 hour..

Wow, tip of the year??

 

[robobass]

50% nail polish remover (don't ask..) + 50% water - softening on Pops and old Neyman (purple container) within 1 hour..

Wow, tip of the year??

Which nail polish remover? Acetone is the traditional solvent, but most are now synthetics. It seems that lots of organic solvents will work for this. I'm very happy, as I have a bunch of dried up old cakes of Nyman and Carlsson which I luckily never threw away.