You would be correct if the polishers are of the "tumbler" type config. and
not the "vibratory" type however, if tumbler comes with rubber jars, they
should be evaluated prior to use as too much rubber may get in the mill mix
by the time your done. Better to use the "tumbler" type rock polisher motor
base w/ a HDPE or LDPE type bottle to minimize contamination.
When grinding pigment it is important to achieve the correct "charge" in the
mill: about 50-60% grinding media (high density alumina, ALO3 is great and
dosn't cost that much) then add your pre-mill liquid sludge to a point just
below the top layer of grinding media in the bottle. You want the the
pre-mill mix to be thick enough to cling to the media, too much water at this
point is not efficent as the mix dosn't coat the media very well and grind
time would be excessively long. The cylinders have more surface area for
grinding and impacting the pigment than do ball type and ALO3 is very hard
and heavy for its size besides, its made specifically for that purpose.
The speed of the motor should be around 50-60rpm for a 1L bottle. When all is
working well, the cylinders cascade down from the top of the bottle (as it
rotates), and tumble down over other cylinders in a continious cycle during
the grinding. Sounds like rain. This will really do a number on anything you
put in there! If you have too much water in the mill, the cylinders just
slide around on the bottom of the jar or bottle. NO GOOD.
Thought......what if they quit making Sumi
Ink??????..........gasp!.................
then we might actually have to do all this. Its really not that bad if you
have all the stuff. You can make custom ink colors in large volumes!
Good Grinding,
Michael Sandquist
>Date: Sun, 20 Oct 96 14:12:47 +1000
>From: sanking@hubcap.clemson.edu (Sandy King)
>Sender: alt-photo-process@cse.unsw.edu.au
>To: Multiple recipients of list <alt-photo-process@cse.unsw.edu.au>
>Subject: Re: dry pigment for carbon tissue
>
>Michael,
>
>Thanks for the detailed instructions regarding grinding dry pigments. If
>anyone is really interested in doing this they may want to check with
>Edmund Scientific. A recent catalog of theirs has for sale several units at
>very economical prices for rock grinding which I think would also work for
>pigment grinding.
>
>
>Sandy King
>Sanking@hubcap.clemson.edu
>
>