On Mon, 12 Jan 2009 22:04:43 -0600, "Maxwell" #$$9#@%%%.^^^ wrote:


"Stealth Pilot" wrote in message
.. .
On Sat, 10 Jan 2009 14:11:47 -0600, "Maxwell" #$$9#@%%%.^^^ wrote:



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What do you use for sand and binder? How do you mix?


you can make your own greensand.

basically you get some buckets of sand. plonk a gently running hose
into the bucket and let it float off everything but the sand.
keep the hose running until the water coming off is clear. this gets
rid of crap and non bentonite clays.

find or buy some bentonite clay.
you can buy sodium modified bentonite in 25lb bags.
you need bentonite clay because of its peculiar charactersitics. it is
different from all the other clays and the difference is what makes it
useful in casting.

ok let your washed sand dry off a bit.
weigh the sand and mix in 5% thereabouts by weight of bentonite.
this is the important bit; you need to put a coating of bentonite
around each sand particle. you dig your clean hands into the sand and
bentonite and with a handfull between your hands you run them back and
forth to work a coating of clay around each sand particle.
(your hands end up really smooth from this)

ok now you let your mix dry right out. this can take a week.

when you want to use the greensand you mix in 5% of water by weight
and nead the greensand so that it is uniformly wet out.

if you pat up a sausage out of it about 2" dia and a foot long you
should be able to hold this by an end and wave it all over the place
and none of the sand will part company.

you then need to do some test pours to see if the porosity of your
greensand means it is too coarse.

if you can handle that intelligently I'll go on to tell you why most
people get their furnaces wrong and what you need to do to get it
right.
Stealth Pilot

What's the point? If you are going to buy bentonite, why not buy a quality
molding sand like silica or olivine as well?

At any rate, good luck on your green strength test. Even the finest seasoned
and mix green sand will in no way meet the expectation of your 2" x 12"
sample as stated.


rubbish.
I *actually* do castings.
the shake test is one I can demonstrate in 5 minutes with two
handfulls of greensand from the black bin in my workshop.
I'm writing from first hand experience.

can I suggest you get off your arse and *do* something in life.
your pleasure would increase immeasurably.

Stealth Pilot