Lead oxide is yellow not white.
Hello,
regarding my previous question about removing the oxide on the characters ( http://www.briarpress.org/23272 ) I’ve discovered lead oxide is yellow, and not white.
For what I know the lead fonts are made mainly with lead, than antimony and tin.
The lead oxide is yellow: http://en.wikipedia.org/wiki/Lead%28II%29_oxide
The tin oxide is white: http://en.wikipedia.org/wiki/Tin_dioxide
and the antimony (tri)oxide is white too: http://en.wikipedia.org/wiki/Antimony_trioxide
What we need to remove is tin oxide and antimony trioxide, not lead oxide, but, is possible to remove these oxides without expensive apparatus or raw materials?!
I believe the only partial solution, like you suggested, is to use a high alkaline product..but in my exoperience this remove just the old ink, not the oxides
Thanks :)
Fabio
Fabio
My understanding is that lead carbonate is the bad stuff, not necessarily lead oxide. I think there is confusion about this. But I believe lead carbontate is the corrosion found in lead (not just type metal) and is white, and is the material used in paint. High concentrations of it make paint very durable; it is used on highways and by the military without restriction. It apparently was the secret to Gutenberg’s black, which he took to his grave (as later revealed by cyclotron investigation).
Gerald
http://BielerPress.blogspot.com
Hello Gerald,
thanks for the clarification…but how can we state it’s lead carbonate and not any other oxide?
I’ve read the lead carbonate is white (http://en.wikipedia.org/wiki/White_lead), but in acid environment it becames dark. In effect my characters are particulary black..and in truth I don’t know if it is caused by the black ink or by the acids in the inks.
Do you now if the letterpress inks are acid?
Thanks,
Fabio
Hi Fabio
I don’t think inks tend to the acidic. That would show in printed matter.
Don’t know that the darkness is the result of anything more than a combination of ink and dirt accumulation. I read that lead does initially turn a slight gray as a reaction to atmospheric gases but this results in a protective coating. I am no chemist though and half of this is likely superstition and suspicion.
If you put the type in a lye bath I’d half-suspect the darkness would be removed?
Gerald
http://BielerPress.blogspot.com
Hello Gerald,
thanks for your interest in my “issue”.
You can read the tests I made with lye and others things on oxidated characters here: http://www.briarpress.org/23272 (on 8 Oct 10 (19:03)
And yes, brushing a bit of lye paste on the characters the black vanishes in a while.
Now next step is to remove the oxide!
Thanks,
Fabio