Homebrew PCBs

On 11/21/2016 8:56 PM, Rob roomberg@... [Homebrew_PCBs] wrote:
>
>
> Not sure if the dating on this make a difference......
> I bought HEWLETT PACKARD
> Disposable Liquid-Ink drafting Pens
> .5mm Medium Point   HP Part no 5061-7620...

<snip>
> ...The package said USE BEFORE JAN 1992 so perhaps I would get a different
> result from
> TODAYs inks instead of using 25 year old ink. Who knows if they even use
> the same chemistry now.
> But for paper.... these are really nice pens.
>
Hello--

I dimly recall investigating the use of an HP 7475 pen plotter for 
ink-on-copperclad
direct trace layout-- the time frame would have been in the very early 
1990s. There
was a fairly substantial amount of correspondence on whatever newsgroup
existed back then, and someone from Canada recommended using a red 
plotter ink made by Stadler (sp?) which provided very good etchant 
resistance.

I attempted to purchase some of the ink, only to be told by the local 
drafting-supplies
seller that the ink contained a toxic ingredient that made its sale 
illegal here in the U.S.
However, the ink was still available in Europe.

At that point, other projects diverted my attention and I lost track of 
the original correspondence. If someone in the group was active back 
then, perhaps they
recall using the ink?

73--

Brad  AA1IP