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K-Bond is named for Kent State where it was developed by one of Tom Cobett's Students.
It is an almost smokless oil bonded foundry sand for casting zinc, aluminum, brass, bronze and iron.
On this page you will find the receipe along with some dos and donts.

Here a US quarter dollar coin was used as a pattern to show the detail achieved with this sand.
K-Bond - Oil Bonded Casting Sand


Density is about .17 lbs per cubic inch. One pound is 5.86 cubic inches.

Prices shown here is what it cost me to make my first batch.

My cost in 2002 per 100 pounds was $31.51 not including freight.


Ingredents:

100 lbs. sand - 100 mesh or finer - US Silica F110

6 lbs. Organo-bentone - Bentone 34 or VG-69

3 lbs. Polybutane (2 US Quarts) Indopol L-100 BP Petroleum or Chevron OLOA

0.2 lbs. (3.2oz or 91grams) Isopropyl alcohol - any pharmacy

- or -

0.2 lbs. (3.2oz or 91grams) Methanol (dry gas) - Auto Parts Store

- or -

0.2 lbs. (3.2oz or 91grams) Propylene Carbonate - Lab-Pro, Inc.


Mixing:

Mix the sand and bentone first, then blend in the oil thoroughly. I have done 10 lb. batches by hand with good results. The bentone is very dusty and the sand contains silica so wear a dust mask!

Add in the alcohol and mix thoroughly. Done!

The sand won't seem like much until the alcohol takes effect and then it will become like stiff cookie dough. How stiff? It boggs down my muller!
It will be much easier to handle when it is a day old and will get easier to use with time and use.
The sand gets powdery after it sits and it is best to mull it or warm it before use.
When green strength starts to fade, add in some alcohol.


 

Sand:

F110 from US Silica

My cost per pound $0.21

$8.95 / 100 lbs. from Abrasives & Equipment of Atlanta

This is an excellent foundry sand. You should try to get it. Check with sand blaster suppliers or contact US Silica and ask where you can get it near you.


 

Bentone 34: My cost per pound $2.76

$138 / 50 lbs. from ViChem in Medley, FL 1-800-325-6109

Made by Rheox.

You can use other organo-bentones as well. One is known as VG-69 and is used by oil drilling rigs. Don't even think about trying bentonite, kitty-litter or speedy dry. They are a completly different thing and I am tired of explaining why they don't work with oil. Try it if you must, but have a hole ready for getting rid of it!


 

Oil: Penzoil synthetic 2-stroke oil: My cost per pound $2.00

From Wal-Mart

$11.95 / 6 lbs. (1 gallon)

The receipe calls for Indopol L100, but it is difficult to get in small quantities (Less than 55 gallons). Indopol is a polybutene and is manufactured by BP as well as Chevron. You can sometimes find it at industrial lubricant distributors who will tap off 5 gallons for you. You can also call and ask for a sample.


 

Gelling agents:

I find propylene carbonate to work the best, but these easier to get alcohols work well.

Isopropyl: Rubbing alcohol from Wal-Mart

Methanol: Dry Gas from Wal-Mart


Here is a post from Tom Cobett stating where he gets his materials:
*************
Dec. 19, 2002
You can purchase a 5 gallon pail of propylene carbonate from the following company for about $150.00 or less. They will ship by UPS.


REFCOTEC Inc. (330) 683-2200
542 Collins Blvd.
Orrville, OH 44667

These guys supply K-BOND materials to commercial foundries. You can buy BENTONE 34 from them also. I doubt if they would sell anything less than a 5 gallon pail or a 50 lb. bag of BENTONE.

Talk with their salesman Randy Gallatin. He has been involved with the commercial side of K-BOND since it was invented about 5 years ago. These are really nice people who have carved out a niche market by manufacturing ceramic coatings, silicate binders, core adhesives, release agents and specialty products for use in foundries.

Tom Cobett
Cleveland, OH

*************


Updated Dec. 28, 2002. Copyright © 2002 Ray-Vin Publishing Co. All rights reserved.