On Tue, 15 Jul 2003 10:57:22 -0400, "C.W. THomas"
wrote:

snip
x-For casting sand, I would reccomend bentonite(cat litter) and sharp silica
x-sand(play sand) throw a little bit of wood flour(dusty byproduct of sanding
x-wood) about 1 cup per 50 lbs of sand mix or you might try graphite (it's
x-purpose is to create a reducing atmosphere in the mold when the molten metal
x-is poured into it).

snip
x-
x-
x-C.W. Thomas
x-
x-
snip


Of all the foundries and casting books I have read, I have yet to read
or hear that woodflour or other additives are for making a reducing
atmosphere. From what I gather it aids in bonding sand grains and
improving surface texture. For the most part, keeping a greensand
simple makes for a better product. he more thats added the more you
have to try and juggle around when it need rejuvinating. Adding wood
flour and such often causes greensand to mold up and get pretty nasty.
I have seen and used sea coal and on occassoin graphite, but it was in
conjunction with a cast iron pour, but it results using the stuff was
ot any better than doing it without, but there are some applications
that do require additon of additives.
--
Visit my website:
http://www.frugalmachinist.com
Contents: foundry and general metal working and lots of related projects.
Regards
Roy aka Chipmaker // Foxeye
Opinions are strictly those of my wife....I have had no input whatsoever.
Remove capital A from chipmAkr for correct email address