I have been reading with interest the creosote dialogue.  Creosote
is classified as a restricted use pesticide in the United States.
Coal tar is the active ingredient in creosote, and I believe
creosote has been determined to be carcinogenic (thus, in part, the
reason for it being restricted, but let's not get off into the
cancer realm).
 
In any case, creosote is a mess to use.  Let me give you a recipe
for a non-toxic wood preservative developed by the U.S. Forest
Service that is simple to make and use and is effective:
 
 
Materials:
 
Exterior grade varnish        3 cups
or
 polyurethane (oil based)     3 cups
or
boiled linseed oil            1-1/2 cups
 
and
 
Paraffin wax                  1 ounce
 
and
 
mineral spirits or            add to make a gallon
paint thinner or
turpentine
 
 
Notes on materials: Boiled linseed oil should not be used in areas
with high humidity as linseed oil is a food source for mildew.  An
exterior grade of varnish, defined as an exterior grade
polyurethane, has more resin and is more flexible.
 
MIX:
 
1.  Add wax to the vehicle (thinner, spirits, or turpentine), then
add varnish.  Stir for 15 minutes to mix.
 
2.  Wax should be in liquid form.  If you use too much wax it will
settle out.
 
Wood can be dipped or brushed with the mixture.  The wax is the
active ingredient, and treated wood will shed water.  You may
recognize this as "home made" Thompson's Waterseal (a popular
American brand), and so it is, just much cheaper.  While this may
not be as good as a hot dip paraffin bath, it is quick and safe.
The only caveat I know is to let the wood dry after treatment
before painting.  I have used this formula a lot in old house
restoration and it really brings old wood back to life, plus it is
cheap.
 
TESTING:  The U.S. Forest Service began testing some 20 years ago.
Window units were dipped for 3 minutes in either a solution of
water repellent with preservatives or water repellants without
preservatives and exposed to conditions in Madison Wisconsin.
Untreated comparison window units completely fell apart after 6
years, but little deterioration occurred in the treated window
units.  There was very little difference between water repellants
with preservatives and those without.
 
Bill Lord
Louisburg, NC  USA
 
WILLIAM G LORD
E-Mail  : wglord@franklin
Internet: [log in to unmask]
Phone   : 9194963344