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Chad48309
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Joined: 26 Sep 2010
Posts: 110
Location: Michigan
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 Posted: Sat Apr 23, 2011 2:52 pm Post subject: |
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| Lemuel wrote: | | It appears that something was done to the varnish years ago and is now or has been changing in chemistry - causing this manifestation. |
Downright funky! I wish I could have one of my chem. major friends do an investigation of a sample.
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Cellobob
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Joined: 17 Apr 2011
Posts: 6
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| Posted: Tue Apr 26, 2011 12:22 am Post subject: |
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Thanks again for all the ideas here. I have contacted a biochemist at the university, and hope that he or a colleague can look at it. I have also asked one of the local luthiers who has seen the cello to monitor your comments on this site, so he can get some ideas from you. He looked at it last year and wasn't sure what to make of the dots - he suggested getting rid of the cloth covering that I had over the cello in the case and to "fumigate" the case, which I did. But the dots have still re-appeared. And even when the cello is in another case.
Not sure about Janito's question: yes, I can remove the dots by rubbing with a cloth (or finger). No, this is not a spoof.
Like Lemuel I have wondered whether there could be a change in chemistry in the varnish. But that doesn't explain the dots on the tailpiece. |
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Chad48309
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Joined: 26 Sep 2010
Posts: 110
Location: Michigan
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| Posted: Tue Apr 26, 2011 11:50 am Post subject: |
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Wait, is the tailpiece original or replaced?
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Cellobob
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Joined: 17 Apr 2011
Posts: 6
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| Posted: Tue Apr 26, 2011 11:52 am Post subject: |
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| I have had this tailpiece on the cello for 30 years. |
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Chad48309
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Joined: 26 Sep 2010
Posts: 110
Location: Michigan
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| Posted: Tue Apr 26, 2011 1:40 pm Post subject: |
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| Cellobob wrote: | | I have had this tailpiece on the cello for 30 years. |
Ah, I was thinking that some original treatment of all the wood parts (as some makers have enjoyed toying with in the past) could have been manifesting now as some sort of chemical change. Depending on how porous the varnish is and has become over time, it could be bleeding out of the pores.
That was just my theory, anyway.
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Janito
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Joined: 08 Oct 2007
Posts: 114
Location: USA
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| Posted: Tue Apr 26, 2011 6:01 pm Post subject: |
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| Chad48309 wrote: | Depending on how porous the varnish is and has become over time, it could be bleeding out of the pores.
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Next you will be talking about the bleeding tailpiece.
OK - here's the deal...let's start with a process of elimination:
- the fungal elements that give rise to 'white' mould are stringy things called hyphae. A simple magnifying system that is >10x will show whether they are present, especially if there are fruiting heads.
- If you mark out a square area on the tailpiece and clean off the spots, how long do they take to reappear? All at once or progressively? Do they enlarge? Are the spots identical on the tailpiece and varnish? Are the spots on the pegs? If you tape a new tailpiece (or wood) safely to the other one, does it develop spots too? Etc Etc
- once we have resolved these questions, we can move onto miraculous chemistry. |
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Dave Chandler
Super Member
Joined: 31 Oct 2007
Posts: 691
Location: Mt Mitchell in North Carolina
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| Posted: Wed Apr 27, 2011 8:27 am Post subject: |
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I agree with Janito, if it were coming from the varnish, it wouldn't be on the tailpiece.
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Southern Violin Association
"Success is the ability to go from one failure to the next with no loss of enthusiasm" Winston Churchill
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