[Boatanchors] Water, Water Everywhere.

WA5CAB at cs.com WA5CAB at cs.com
Fri Dec 11 20:02:10 EST 2015


Brian,

The problem with the bakelite inserts in the WW-II Large Banana Pin style 
connectors that Dave alluded to earlier is that they swell, not shrink.  The 
increase in diameter 70 years on in about 250 samples that I have here is on 
the close order of 0.002" per inch of diameter.  As found, the inserts are 
impossible to remove from the cylindrical bodies without at least an arbor 
press.  Sometimes the bodies actually split from the swelling.  Dave 
discovered experimentally and I have confirmed numerous times that one to two hours 
at around 150F followed by cooling to ambient was sufficient to allow insert 
removal with only ones thumbs.  Otherwise, in order to reassemble a 
connector after using a press to remove the insert required reducing the OD with a 
lathe.

In a message dated 12/11/2015 18:06:16 PM Central Standard Time, 
brianclarke01 at optusnet.com.au writes: 
> Some 'plastics', eg, bakelite and other phenolic resins that have been 
> used 
> to make coil formers, gradually lose whatever water was in them, and 
> shrink.
> 
> 73 de Brian, VK2GCE.
> 

Robert & Susan Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480


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