[Boatanchors] Re: Loc-tite soaked set screws

[Barry L. Ornitz]

Bob Mattson, W2AMI, asked about loosening setscrews sealed 
with Loctite.  Several people suggested heating the joint, and 
finally in the next digest, John Forster suggested heating the 
Allen or spline wrench with a soldering iron to transfer heat 
to the setscrew.  This is about the best method I have found.

Several people suggested solvents.  In general these will not 
work.  The cleanup solvent for Loctite is only useful for the 
material that has not completely polymerized.  Once fully 
cured, few solvents will attack the cyanoacrylate polymer.  
Someone else suggested GC-Thorsen "Service Solvent."  Not 
being familiar with this, I looked it up.  It is approximately 
30 percent each of acetone and toluene, and 20 percent each of 
butyl and ethyl acetate.  This is pretty flammable and it will 
certainly attack many plastics, but it will not do much to 
Loctite thread sealers.  It probably works well for earlier 
thread sealers which were just simple plastics dissolved in 
solvent much like model airplane glue.  

Heating the Loctite material above its glass transition 
temperature is the best way to soften the glue and loosen 
these threads.

Tennessee Eastman Division of Eastman Kodak was the home to 
the invention of these cyanoacrylate adhesives.  Dr. Harry 
Coover was the chemist who was working on new polymers in an 
attempt to find a more shatter resistant plastic for aircraft 
windshields.  Fred Joyner (appropriate name!) was his 
technician doing most of the laboratory work.  One day,
Fred placed a sample of a monomer solution between the prisms 
of an Abbe refractometer to measure the refractive index of 
the material.  After the measurement, he could not pry the 
prisms apart.  He tried several solvents without success.  
Coover recognized what had happened - the material did not 
polymerize while exposed to air but rapidly polymerized under 
pressure when the air was excluded (anaerobic).  This led to 
the dvelopment of Eastman 910 adhesive, the original 
superglue.  Tennessee Eastman split from Kodak a few years 
back.  All of the patents and rights for the line of 
cyanoacrylate adhesives was sold to Loctite Corporation.

Fred Joyner kept the original refractomer in a glass case in 
the corner of his lab and displayed it proudly.  His lab was 
just down the hall from my office at one time.  After he 
retired, his lab was renovated and the famed refractometer 
disappeared in the cleanup.

        73,  Dr. Barry L. Ornitz     WA4VZQ     ornitz@tricon.net