Definitive Article on K-Bond

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K-Bond is an oil-sand casting formula from 1995.

The definitive source:

Subject: The History of K-BOND Message: 3 Date: Wed, 13 Feb 2002 13:05:03 EST From:

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...

Tom Cobett

Cleveland, Ohio

The above was copied from, in case it disappears.