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Subject: Naval jelly

Naval jelly

From: Paul Storch <paul.storch>
Date: Wednesday, December 16, 1998
Mary Todd Glaser inquired about how to deal with a "thick, dark,
gummy substance" that is "sticky to the touch" that was applied
about 13 years ago to iron alloy surfaces on large functional
objects.  This substance is probably not "naval jelly".  It sounds
like the museum staff is not familiar with object treatments of any
level and is confusing the names of substances that have been
traditionally used for metal cleaning and long-term preservation.
Naval jelly is the commercial name for a thick paste that contains
phosphoric acid.  It is used for removing corrosion and flash rust
from metal parts.  It  needs to be rinsed off after about 10-15
minutes, and was never intended to be left on indefinitely.  The
residual phosphorus serves as a passivating agent, i.e. it occupies
the reactive sites on the metal surface thereby 'locking' out
oxygen, but the carrier is washed off.

What Mary saw is most likely a petroleum jelly of some sort, or
perhaps "Cosmoline" which was/is used by the military to pack Jeep
parts and other equipment for long term "moth-balling".  It is a
heavy weight petroleum by-product that helps to protect the metal
surfaces from corrosion due to the hydrophobic properties of the
paste.  The substance could also be a product sold as "RIG" (Rust
Inhibiting Grease).  RIG is sold by gun shops and hardware stores.
It is sulfonated petroleum jelly.  The sulfur serves as a
passivating agent on the metal surface, i.e. 'locking up' reactive
sites on the metal from oxygen that might penetrate the jelly layer.
Any of the petroleum jellies should be removable with a mineral
spirit/hydrocarbon solvent.  My opinion would be that an experienced
objects conservator with a specialty in large functional objects
should be called in to do some analysis and treatment tests, and to
develop a protocol for cleaning.  Just from the information given
about this situation, I would say that this is not a volunteer level
project at that institution without further training and
supervision.

I hope this helps, and feel free to contact me off-list with further
questions.

Paul S. Storch
Objects Conservator
Daniels Objects Conservation Laboratory (DOCL)
B-109.1, Minnesota History Center
345 Kellogg Blvd West
St. Paul, MN  55102-1906
651-297-5774
Fax: 651-297-2967

                                  ***
                  Conservation DistList Instance 12:52
               Distributed: Wednesday, December 16, 1998
                       Message Id: cdl-12-52-004
                                  ***
Received on Wednesday, 16 December, 1998

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