First, let me echo David's caveats. Using solvents in small quantities reduces the risks, but caution should always be paramount.

Second, the solvent selection for the different Paraloids (formerly known to many of us as Acryloids) may have several different factors influencing the final choice. It is not clear from the original post if B-72 is applied as a barrier layer with B-67 as the numbering layer. If so, many of the solvents listed in Fred's response will dissolve both resins, an unintended consequence. The general advantage of B-67 is that it can be dissolved in naphtha and mineral spirits without dissolving B-72, so the top layer can be removed from the bottom layer. As pointed out, Naphtha should be available in many hardware stores. If not, paint thinner (mineral spirits) will work fine to dissolve fresh B-67. However, it must NOT be odorless paint thinner, which will NOT dissolve B-67. Obtaining regular (not odorless) paint thinner may be a problem in some states, depending upon their specific laws. If only odorless paint thinner is available or if the B-67 has aged to the point that regular mineral spirits does not dissolve it, add a SMALL amount of acetone to the mineral spirits. Generally, this should be no more than 5% or a mixture of 1 part acetone to 19 parts mineral spirits. This should do the trick. If it does not, add a tiny bit more acetone until it is effective. If the acetone amount is too great, it will dissolve the underlying B-72, or for that matter, many historic coatings that may be present.

Rohm & Haas has a chart of solvent selections for the various Paraloid resins, but it is not easily located on their web site. I have been in contact with them, and once I receive the information, I will post it to the list.

American Conservation Consortium, Ltd.
     4 Rockville Road
     Broad Brook, CT 06016
     www.conservator.com
     860-386-6058

*Collections Preservation Consultation
*Conservation Assessments & Surveys
*Environmental Monitoring & Low-Tech Control
*Moisture Management Solutions
*Collections in Historic Structures
*Collections Care Grant Preparation
*Conservation Treatment of:
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Marc A. Williams, President
     MS in Art Conservation, Winterthur Museum Program
     Former Chief Wooden Object Conservator, Smithsonian Institution
     Fellow, American Institute for Conservation (AIC)

----- Original Message -----

From: [log in to unmask] href="mailto:[log in to unmask]">Frederick Van de Walle

To: [log in to unmask] href="mailto:[log in to unmask]">[log in to unmask]

Sent: Wednesday, March 10, 2010 1:23 PM

Subject: Re: [MUSEUM-L] Object Labeling

B-67 and B -72 dissolve in:

Acetone
Amyl Acetate
n-Butanol
Cellosolve
Diacetone Alcohol
Dimethyl Formamide
Ethyl Alcohol
Ethylene Dichloride
Isopropanol
Leksol
Methylene Chloride
Methyl Ethyl Ketone
Toluene
Xylene

I would recommend Isopropanol and Ethyl Alcohol and mixture of Ethyl Alcohol / Acetone

Fred Van de Walle

From: Rosie Cook <[log in to unmask]>
To: [log in to unmask]
Sent: Wed, 10 March, 2010 10:45:30
Subject: Re: [MUSEUM-L] Object Labeling

Becky,

You can by Naphtha at your local hardware store (Home Depot or Lows). It is usually in the paint removal isle. The only other thing that I have found that removes the layers adequety is acetone and I would not use that except on glass.

Rosie Cook

Registrar & Assistant Curator
Chemical Heritage Foundation
315 Chestnut Street
Philadelphia, PA 19106
Phone: (215) 873-8215
Fax: (215) 629-5215

From: B Glasby <[log in to unmask]>
To: [log in to unmask]
Sent: Tue, March 9, 2010 12:04:45 PM
Subject: Object Labeling

I use B-67 & B-72 (where appropriate) when labeling object ID numbers and have recently found that Gaylord does not sell teh Naphtha solvent individually. This solvent is used to remove the B-67 number coats when needed.

Is there somewhere to buy this sovlent so the number can be removed? Or should I be using something else to remove the numbers?

Thanks!

Becky
National Electronics Museum
[log in to unmask]

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