[QuadList] Toluene

[C. Park Seward]

Tim,

Thanks for your great reply but you didn't say anything about Xylene. Can you compare and contrast with Toluene?

Also, some Ampex audio equipment users recommend lighter fluid.

Some comments from the Ampex list:

 I would be especially careful about using any of the high concentration alcohols for head cleaning, because these alcohols are hygroscopic and absorb water vapor out of the atmosphere.  This does two things, first it rapidly dilutes the alcohol to the point where it won't dissolve the tape binder goop, and secondly, it leaves some water on the iron head laminations -- especially, making use of the low surface tension of alcohol-water solutions, getting down into little crevices in the head stack  which may in time rust them and disturb the precise alignment of the head laminations.  Xylene is not the least bit miscible with water and so you don't have this problem with it.

 Xylene is the best product for the purpose.  It doesn't damage epoxy encapsulations or iron head laminations, and it DOES cut the tape binder goop very well - even when it's gone sticky.

I spoke with my rubber vendor the other day, and he suggested ethyl alcohol
for routine cleaning of nitrile/buna-N pinch rollers.  It's not that
expensive and it is generally available.

Isopropol, even the 99% pure stuff, WILL eventually damage the plastisizers in your rubber and it WILL make your pinch rollers hard. You can't avoid the chemistry on this. Pure ethyl alcohol (without organic stuff making a stiff drink) is OK on pinch rollers but it's extremely expensive in these parts. At least if you get bored you can make yourself a high test adult drink ROFL.

I've always used ethyl alcohol.  In liquor stores (Everclear brand) or by
special permit in some locations (such as Washington State, where sales of
grain alcohol are banned).  Non-toxic when used as directed <grin>.

Ampex head cleaner: 86% of Xylenes (O-,M-,P- isomers) and 14% of Methyl Chloro (1,1,1-Trichloroethane)

 Tri Chlor  used to be cheap, worked well and did what not too many other solvents could. When  you walked into a dry cleaning store  did you ever wonder why they were always smiling?

 Xylene is a component of lacquer thinner and it keeps the body shop  workers HAPPY.

 Methylene Chloride is the King of the solvents. It will dissolve a cross linked  polymer overnight. I used to buy it  40m drums at a time for 60 bucks a drum; now it's around $180  for a five gallon pail.



Best,
Park

C. Park Seward
Visit us: http://www.videopark.com




On Jan 14, 2010, at 4:03 PM, Tim Vitale wrote:

> How did you identify the binder as latex rubber?  
> 
> Later videotape (1/2" R-2-R and later, for sure) used polyurethane as
> the medium for the magnetic pigment (that what it's called) on an
> cellulose acetate or polyester base.  Polyurethane degrades by
> breaking off small chains (under acid hydrolysis) of the long urethane
> polymers, which clump together as "gunk" that was known as the Sticky
> Shed Syndrome.  There will be magnetic pigment particles in the
> "stuff" stuck to the head, cap stands, guides and wheels.  The "stuff"
> should be nicely soluble in toluene.  However, toluene is quite toxic,
> especially if you get it on your skin.  Toluene is a benzene ring
> (cancer causing) with a methyl group (CH3) on one of the six carbons
> in the aromatic ring.
> 
> As a conservator with some age on me, I have been guilty of doing what
> you have done, and of holding your views.  We had a number deaths in
> the field years ago that were attributed to solvent use, however, not
> just toluene use.  We, and I, are much more cautious now.  Toluene
> does work its way out of the systems in time
> http://en.wikipedia.org/wiki/Toluene, but it is one of the slower
> ones, if memory serves.
> 
> I'd use a solvent that does the job (maybe not as quickly or with more
> elbow grease), but is less toxic, or one that is more easily removed
> by the body's defenses.  I'd try acetone first, then methyl ethyl
> ketone (MEK).  They are both in the ketone group, which our body makes
> when burning fat under a low carbohydrate diet; you know, ketosis. You
> can find all the above solvents (and many more) at Home Depot; even
> toluene.  They generally run about $4-7 per quart.
> 
> There is a complex Teas solubility process that is used to estimate
> solubility.  I can walk you through it, if you like.  I'll have to fax
> you some charts and diagrams.
> 
> BTW, toluene will go after quite a few plastics.  I would not consider
> it safe for plastic-laden equipment.  Alcohols (specifically,
> propanol) are generally the only solvents that get a pass for use on
> equipment.  
> 
> Best of luck...
> 
> Tim Vitale
> Paper, Photographs &
> Electronic Media Conservator
> Digital Imaging & Facsimiles
> Film [Still] Migration to Digital Format
> Digital Imaging & Facsimiles
> Preservation Associates 
> 1500 Park Avenue 
> Suite 123
> Emeryville, CA 94608
> 
> 510-594-8277
> 510-594-8799 fax 
> 
> tjvitale at ix.netcom.com
> Vitale bio
> http://videopreservation.conservation-us.org/tjv/vitale_1pg_bio.pdf
> Resume: see link in lower right corner of the URL above. 
> Albumen Photography Website in 2000
> <http://albumen.conservation-us.org>
> VideoPreservation Website in 2007
> <http://videopreservation.conservation-us.org>
> 
> 
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