I think that you'll find this info helpful.
Subject: The History of K-BOND
Date: Wed, 13 Feb 2002 13:05:03 EST
K-BOND was developed in about 1995 at Kent State University. The Metal
Casting program at KSU had been using Petrobond for about 20 years. One day
we got a visit from the local environmental person who wondered if the
building was burning down. (we had just finished pouring) When they found out
that we were putting motor oil into sand and then causing it to burn by
pouring liquid metal into it, well, let's just say that we were told to stop
using Petrobond - IMMEDIATELY!
We learned that exposure to burning motor oil, and repeated skin contact with
motor oil, can cause cancer.
We set about to find a suitable alternative. After about 3 months of testing,
we had evaluated many sources of bentone and many sources of "smokeless"
oils. (By the way, Petrobond is also made with Bentone.) We found that
virtually all organo-bentones will work well. With this in mind, we bought
the cheapest one we could find.
For the oil, we settled on AMOCO Indopol L-100. This was listed as being a
"food grade" material that burned cleanly. Later, we found out that Indopol
is the main ingredient of most smokeless 2-stroke oils.
The basic recipe for K-BOND is:
100 lb. of very fine silica sand (100 to 150 GFN)
6 - 7 lb. of Bentone (cheapest you can find)
3 lb. of Indopol L-100 oil
0.10 to 0.20 lb. of Propylene Carbonate (or Methanol or Isopropanol)
If the sand become too dry to mold, we add more Indopol. If it lacks any
strength, first we add more Propylene Carbonate. If that does not bring up
the strength, we add more Bentone.
We have used this stuff several times a week for aluminum, bronze and iron
castings. We have never thrown out the pile, we just add too it. We don't get
a room full of blue haze when we pour our molds. We are not exposing our
students to a cancer hazard. AND, the best part, we make castings that are
incredibly smooth with extremely fine detail.
I am personally very pleased that some of you have taken the initiative to
use K-BOND. It is safer and cleaner to use than Petrobond. With some creative
purchasing, it should be cheaper than buying Petrobond.
Dedicated to Metal Casting Education...