Subscriber Frank Foster, 25 Abbey St., Fairhaven, Massachusetts,
sent in copies of two ‘Letters to the Editor’ of Stationary
Engine magazine. He thought they would be of some interest to his
fellow subscribers. We therefore reprint them with gracious
permission form Stationary Engine.
The first letter, which appeared in the August 1994 issue of
Stationary Engine, was written by Bryan Robert, Rad-book Green,
Shrewsbury, and reads as follows:
‘Dear Editor: In David Edging ton’s article in the April
(1994) issue he mentions the frustration of the restorer who is
missing the spec plate. I have had some success etching a brass
plate in the way the electronics enthusiast makes his printed
circuit board.
The first step is to lay out some etch resistant lettering on a
brass plate; transfer lettering (Letraset) with its various styles
and sizes is ideal. For borders and larger areas, shapes cut in
plastic electrical tape rubbed down hard on the surface, can be
used. Curves, etc. are filled in by hand, using model paint (curves
are available on Letraset Ed.)
‘The completed mask is then placed with the etch ant in a
plastic tray (margarine tub) which, if floated in a bowl of hot
water (to speed reaction), will etch sufficiently if agitated for
10 to 15 minutes. If left too long, the lettering may be
undermined.
‘After etching, the masking is removed (cellulose thinners
work well for this) and the whole plate is given a light ‘blow
over’ with matte black aerosol. The tops of the lettering can
then be polished with some fine emery paper on a flat block.
‘The et chant used is ferric cholo ride, which is available
from Tandy Stores or your friendly chemist. For those not familiar
with this stuff, be wareit’s poisonous, corrosive and will turn
your bathroom suite, clothes, fingers etc. a nasty yellow!
‘I recommend doing some experiments before an elaborate mask
is made, but my results were quite successful.’
Mr. Robert’s letter was followed two months later, in the
October 1994 issue of Stationary Engine, by a letter from Eric
Brain, Clutton, Bristol, in which Mr. Brain related the following
story about plate etching:
‘Dear Editor: The letter from Bryan Robert in the August
1994 issue could not have come at a more opportune time.
‘I have a Hewlett & Blondeau Omnia engine (subject of an
article in Stationary Engine issue No. 198), which is missing a
serial number plate.
‘With a view to making a replica plate I had already found a
photograph of one, which was kindly supplied by Philip Galli more
some years ago. I scaled it up, using my existing screw hole
centres on the water hopper as a standard.
‘The very next day my Stationary Engine magazine arrivedlo
and behold, Bryan Robert was advising on the very method with which
I intended to try an experimental nameplate.
‘By the end of the week I obtained some ferric chloride
crystals from an electronics shop ( kilo for 1.75) and made a trial
plate which, on completion, so exceeded my wildest hopes that
further attempts were not necessary. The plate was left in the
solution of hot liquid et chant for 1 hour 10 minutes, which gave a
perfect depth with minimal undermining of the masking.’
