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Old 03-02-2011, 10:05 PM   #6
pmdec
 
Join Date: Nov 2006
Location: France
Posts: 441
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Hi Adrian,

Preserve old props is very difficult. In the field of aviation, people tend to put everything constantly new. The result is old props sandpapered (even "Kärcherized") and bright from epoxy varnish... Even in museums. What a pity!

So, what to do?
First, I agree with you not to use oil: it is too risky it will unstick a decaying varnish.

From some times, I thank to use shellac to preserve props. I have bought some different kinds (see below) of flakes. I tried different recipes on old piece of wood and it seems perfect, but using it on prop which have their decals makes me dubious... ... So, for now, I have do nothing as I am afraid to make some mistake.

I have some questions about shellac, and the first one is what are you talking about: is it this very one http://en.wikipedia.org/wiki/Shellac ?
Or synthetic ?

The first (the true) one seems to be sold in France as "gomme laque", which comes with many kinds and colors. The two main kinds are:
- natural (contains wax): the flakes are a little flexible,
- wax free: flakes are brittle (I'm not sure of the word).
And both are coming in many colors from light yellow to dark brown. Which one are you using?

Second question: which solvent? Alcohol? Ethylic? Isopropylic? Pure? 95°? 90°? Less? And how much flakes?

Third question: how to use it? With a brush, or by using traditional French Polish method?

And the last question, which should to be the number zero: before shellac, what do to for not sealing the dust inside the small cracks of the old varnish? Soft dry brush? Water seems "forbidden' as it will impregnate and discolor the wood? Alcohol?

So ... I understand I am asking for a complete (and free) preservation course! But i'ts all for the sake of old props!

Regards,
PM
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