Bruce wrote:
>I need some help for the chemists here, but linseed oil, boiled or not,
> with heavy metal dryers added (highly toxic, by the way) or not, will
>never
> really dry. It creates, I believe, a non-polymerizing film
Boiled linseed oil will polymerize but it takes several days at best. The
dryers don't actually dry anything but are present to hasten the
polymerization process which would otherwise take place in a geologic
time frame.The resulting film is softer than resin based varnishes to be
sure. Hand rubbing will speed the polymerization process, apparently
through the heat of friction, and appears to me to be the 'secret' in
using this finish. Hand rubbing a pair of french doors would not appear
to be a practical endeavor.
>If you are planning to use a varnish, can I suggest that you use
> water-based polyurethane. It is very easy to apply, kind to brushes (goes
> on excellently with sponge applicator) and the environment, offers great
> protection against abrasion and chemicals, doesn't yellow the way the old
> polyurethane's did, creates a better bond to wood than traditional
> polyurethane, and can be manipulated to look like a shellac finish with a
> little practice.
Water based poly can also make a great, non-yellowing coating for
abrasion resistance over latex paint. One caveat concerning water based
polys is that the abrasion and chemical resistance can vary wildly from
brand to brand. FWW did a comparison of several brands a couple of years
ago (FWW #115, p. 48) and found that a couple of brands (formulated for
spraying) offered no more protection than an acrylic floor polish.
****************************
Tom Price
Just say there were some interesting letters in subsequent issues, etc.
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