Silicone creep

[Mike Swendsen]

Tim:
Thanks for the information on silicone and its removal.   I never understood
the chemical process.   I just knew what worked.

Now we are much smarter.  :)

-----Original Message-----
From: Tim Keenan & Rebecca Counts <tkeenan@kermode.net>
To: pianotech@ptg.org <pianotech@ptg.org>
Date: Tuesday, March 17, 1998 11:03 PM
Subject: Re: Silicone creep


>ralph m martin wrote:
>>
>
>> Some of the houses selling furniture touch-up supplies also list mineral
>> spirits for the removal of silicone
>
>in response to Mike Swendsen's>
>
>> >The only solvent that will clean silicone is naphtha......
>> >try that and you might be able to glue the parts....
>> >maybe
>
>In fact, any non-polar solvent will do the job--the more non-polar the
>better [water is very polar, alkanes are non-polar, and alcohols are in
>between.] That means alcohols are not too good, and the heavier alcohols
>(propanol, butanol, etc) are better than the lighter ones (methanol and
>ethanol), but will have the unfortunate tendency to form hydrogen bonds
>with the cellulose in the wood --bad idea--polyethylene glycol is a heavy
>alcohol. Lower molecular weight alkanes like naphtha (kudos to Mike for
>spelling) are good candidates. If you want really good performance at some
>risk to your health and that of the environment and the ozone layer, try
>perchloroethylene or methylene chloride.  The trick, if you are removing
>silicone oil from a finished surface, is not to dissolve the finish too.
>That is probably the reason furniture types recommend the less aggressive
>mineral spirits.  I think that when you are talking about gluing, however,
>you are probably talking about an unfinished surface in most cases, and
>there you have a problem.  You can probably never practically remove *all*
>the silicone oil from a piece of unfinished wood once it is contaminated.
>You may be able to remove enough to get a good glue bond, but it will
>require several washings in the solvent of your choice.  Many tropical
>hardwoods are notoriously difficult to glue because of their high oil
>content (teak in particular), but they can be treated in this way, just on
>the surface to be glued, and once the glue has penetrated the temporarily
>oil-free cells on the gluing surface and set, it cannot be subsequently
>displaced by the oil leaching back in from cells deeper down (presuming the
>cured glue is not soluble in the oil in question).
>
>(--i studied wood technology as well as chemistry and biology in a former
>life--
>
>Tim Keenan,
>Terrace BC