ignition reference

[Gordon Couger]

>From a previous life in  the printing industry I recall that the undercut
cut etching processes was countered with dragon's blood. Resin if I recall
correctly. Any text on etching from the first half of the century should
address this. In fact I think the problem is addressed as early as the 
17th century by artist.

Good luck
Gordon

>
>> >We were going to make soft copper head gaskets for high compression
>> >conversions for older off-beat engines that there are no kits for
>> >by using sign writing vinyl which can be cut to 0.25 mm accuracy
>> >without any trouble.  We have a set of vinyl masks which would
>> >be about right for a chainsaw but have not had time to try out the 
>> >setup.  With copper it is easier, you take some ferric chloride
>> >and sulphuric acid and then REVERSE electroplate the  holes into the 
>> >sheet with the vinyl mask protecting the gasket.
>> 
>> If anyone cares, I can elaborate on pros and cons of each.  Don't
>> have much success with anything very thick (that requires spraying
>> the etching solution to lessen 'undercut').
>

Gordon Couger Senior Software Specialist
Biosystems & Agricultural Engineering Dept.  Oklahoma State Univ.
114 Ag Hall Stillwater, OK 74075
gcouger at master.ceat.okstate.edu