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Re: Epoxy Coating Removal



Jon:

Is media blasting out because you cannot get the proper line of site or
because the media mar the intake surface.  Liquid CO2 media can effectively
remove coatings -- the thermal shock does quite a job.   I'm sure
dimensional stability is important to the intakes, but by subjecting the
intakes to cryogenic temps (liquid N2 for example) via "blasting", the
differences in the thermal coefficient of expansion of the metal and the
coating might be enough to separate the coating from the aluminum ..........

Another technique I have seen used is for cleaning paints out of glass
lined reactors (which are very sensitive to blasting).  Here they put water
in the tank and an ultrasonic transducer -- the ultrasonic waves cause very
powerful (but very isolated) impacts right at the interface of the coating
and the substrate -- the coating is stripped off and (if I remember
properly), no chemicals were required.  For you application, it would
require constructing a tank to hold the intakes and dropping a big
transducer in.  Obviously, bench tests would be a first step here......



At 10:54 AM 12/15/00 -0700, you wrote:
 >Greetings and Happy Holidays to all P2 Techers -
 >
 >We are working with a firm which remanufactures turbine engines.  The
 >aluminum alloy intakes of the engines are coated with a very tough epoxy
 >paint.  The current material used to remove the epoxy is Turco Transpo,
 >manufactured by Turco Products, Inc.  While very effective, this chemical
 >is extremely hazardous.  It is composed of approximately 10% cresol, 55%
 >dichloromethane, <1% Sodium chromate, and <5% sodium phenolate.
 >
 >Does anyone know of a safer, less hazardous alternative?  Media blasting
 >is, unfortunately, not an alternative in this application.
 >
 >Thanks for your assistance -
 >
 >Jon Hudson
 >******************Montana P2 Program*******************
 >
 >Jon Hudson
 >Pollution Prevention Technical Specialist
 >MSU Extension Service
 >Taylor Hall                             (406) 994-3451
 >Box 173580                              (fax) 994-5417
 >Bozeman, MT 59717-3580        toll-free (888) MSU-6872
 >
 >jhudson@montana.edu
 >http://www.montana.edu/wwwated
 >
 >*******Pollution Prevention Makes Business Sense*******

Tim Greiner
Kerr, Greiner, Anderson and April, Inc.
47R Englewood Road
Gloucester, MA   01930
P: 978-525-2214
F: 978-525-2247