Posted by bpfink on April 14, 1999 at 09:08:42:
In Reply to: Kenset oil bond sand posted by William Boyer on April 13, 1999 at 06:38:49:
Depends on where you live but look up Foundry Supplies in the Yellow Pages
or go to the web and check that out
or go right to the Kenset web.
Here in New England and Boston area I get it at
FOUNDRY SUPPLIER Malcolm G. Stevens, Inc. in Arlington, MA at (781)648-4112.
But a brief additional explanation of what it is:
The Kenset is an oil activated binder for many sands.
The oil hardens when put in contact with a smaller amount (1/3) of catalyst that is an acid. So you need to order both parts.
The SAND is just dry sand and depending on who you ask they will try to sell you their preference. Silica sand works but very fine sands will give a finer surface. Also the finer sands can be used nearer the surface and larger amounts of backup sand of a lesser quality can be used to save money.
I have paid up to $15. per hundred lb. for good fine dry sand with another $90. for the freight or delivery of 1 ton of it.
Also paid $.03 / 100 lb. (yes that is cents) for damp brick sand in a 14 cubic yard load including the delivery. No question what I will back it up with once it has been predried.
That is accomplished here in 2 ways...
first is to spread it out in the sun on plastic for a hot day or two in the sun...
second is to use the backup sand adjacent to the sunken burnout kiln body after a 7 day firing....
Then screen it in a modified cement mixer with holes cut in the side and a series of variable screen insets that fit in for whatever maximum grain size I need. Can handle, sift, and bag or drumup about 1000 lb in 30 minutes.
I normally use this sand for the entire casting sand mold / so still have 2/3 of that 1 ton of dried super stuff in storage.
Now to mix the batch.
Proportions vary by sand, fineness and temperature... but as a general concept rule I have found these proportions good for the dried brick sand mix.
To 3 gallons of sand in a 5 gallon bucket add
4 oz. Catalyst acid and mix
12 oz. oil and mix
These proportions may seem too strong for your sand and you may cut it way back but the finer flour like particles in the sand I use needs this proportion for a good hard mold.
Commercially they use a large wheel barrow sized Muller mixer with rolling wheels turning around in the mix to do a good crush/mulling/ mixing. I don't have one.
For small batches and large enough for all my uses:
First take the determined amount of sand needed and put in a plastic type bucket or container.
Several successive batches can be made to get more if needed.
Then use some sort of drill or larger paddle mixer to mix in the CATALYST acid first.
I pour it between 2 buckets for a complete mix. The mix now looks nearly the same but is only very slightly dampened with it. Hard to detect a difference yet so adding any powdered coloring to also test the efficiency of the paddle may be needed the first time.
SECOND add the oil (always second and about 3 times the volume of the acid) and mix again. Pour between the 2nd bucket to make sure to thoroughly mix well.
That is it.
Use it and watch it harden up in about 25 to 30 minutes depending on temperature of the sand and environment. I always let set overnite if possible, or at least several long hours.
Lots of finer details and tricks for a great mold and superior surface but too detailed for this right now.
These molds are good for BOTH non ferrous metals and cast iron. bruce paul fink