I've just been refurbishing a box of assorted spokeshaves - and best
of all I've finally got a Preston quirk router !
One thing I noticed is that japanning falls off when you leave it in
the electrolysis tank. Now this isn't news, but there was a very
obvious variation between US Stanley japanning, that barely shifted
unless already damaged, English Stanley japan that came off readily in
big sheets and Preston's japan that turned to mush almost instantly.
That set me thinking - _Why_
does japan come off ? I wouldn't expect
it to be affected by the current and my tank electrolyte is cold and
has a fairly neutral pH. The only reason I could think of is that the
English Stanley japan is permeable and there's some electrolytic
effect happening underneath it that destroys the adhesion. US japan
doesn't appear to detach unless the underlying iron is already
rusting, and then only by lifting around the edges. Presumably
Connecticut japan is itself impermeable.
Any thoughts ? Anyone know the various recipes used and if they did
vary like this? I'd have thought all these japans had a pretty high
bitumen content and that makes a fair electrolytic etch resist on its
PS - A "quirk router" is spokeshave look-alike that cuts narrow, deep
grooves. The cutter is a double sided affair, made from a strip of
thin sheet. The business end looks like a C shape, one side cutting
the sides of the groove and the other ploughing the bottom - like a
tiny plough plane with twin nickers. Sharpening is an interesting
exercise with a tiny diamond hone!
'Ph'nglui mglw'nafh Cthulhu Evesham wagn'nagl fhtagn'