Bill Coburn (22.214.171.124)
|Posted on Friday, 21 June, 2002 - 21:56: |
Can someone tell me how engraving is done on bakelite and metal. The switchbox for instance is aluminium as I recall with the 'Off S & T H S & T" etc either engraved or cast into the surface. The whole thing appears to be painted by some process and the engraving filled with a white material. A similar situation exists with the bakelite knobs. The switchboxes I have stripped to bare metal then forced masking tape into the lettering I then carefully sand the surface leaving the vestigial tape behind. Powder coating follows then I sit down with a good single malt (helps the concentration) and carefully scratch out the tape from the lettering then fill it with white out otherwise known as correcting fluid for typing!
I can't imagine any factory doing all this. There has to be another way!
|Posted on Friday, 21 June, 2002 - 23:32: |
The answer to your initial question is to get hold of a dental handpiece or engraving tool. Use a round burr to tidy up or deepen as necessary the existing letters (of which surely there must be some vestige).
If you're feeling really brave you could us a cylindrical (Fisher?) burr vertically and get nice clean edges and uniform width to the letter lines. It needs a steady hand and nerves of steel, though. I don't think Scotch would help.
A burr would also be the ideal way of cleaning out the lettering after powder coating or painting.
I seem to recall that Jim Kelso wrote an article for Praeclarum some time ago describing how he restored the switch face on a 20HP. The white material he used to fill the lettering may well have been white-out.
The basic technique is usually one of filling the grooves and then swiftly wiping off across the surface to leave a clean intaglio of white.
(Incidentally, did you know that "Tip-Ex", the original whiteout, was invented by the mother of Mike Nesmith, the beanie-hatted member of "The Monkees"?)
Lex Lynch (126.96.36.199)
|Posted on Saturday, 20 July, 2002 - 15:48: |
Dear Bill - From Lex Lynch and Audrey B111 JN
I spent a long time pondering this problem and eventually the answer was simple. The metal body of the switch box is taken back to bare metal, then sprayed with a low gloss spray pack allowed to dry thoroughly then after a visit to the local art shop to purchase a Staedtler Chinagraph pencil you can rub this accross the engraved surface for a factory finish. Any excess will clean off with Turps - easy. Also works on the steering hub. As for the bakerlite knobs I recall using a fine brush and enamel paint. Good luck. PS I still remember your speech about MK V1 's decending from Heaven - Lex
Bill Coburn (188.8.131.52)
|Posted on Wednesday, 24 July, 2002 - 11:38: |
Chris and Lex/
Thanks for the advice - my apologies for the delay but I have been a little peripatetic of late. Actually Lex I did SDB 94's switches etc as you recommend. I notice that the 85 Spirit I attempt to destroy from time to time appears to have glue on lettering (Letraset?)so maybe the little gnomes who used to scratch around these things finally went to gnome heaven and engraving is no longer practical.
As to your piece of trivia Chris that shall be stored and dropped on some impressionable group on a future occasion.