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Casting Sand


#1

I’m going to start sandcasting soon and I have all my necessary
equipment, except for sand. I’m looking for some ideas for casting
sand. Pet stores have nice fine sand but they want way too much for
it (I am a cheap man when it comes to buying crushed rock). Any
suggestions will be fantastic.

Thanks,
Scott Thomson


#2

Hi Scott

Try one of the kid’s party stuff supply houses like Oriental
Trading. They carry sand for sand art projects and it’s not
expensive.


#3

Scott,

You might want to experiment with a bag of portland cement mixed with
motor oil. Navajo Indians, years agoin in the Gallup NM area, used
this combination to pour thounsands of ounces of tradition tuffa cast
sterling designs. Guess you could call it an “old Indian trick”. I
heard from an old timer it was used way back to duplicate Model T
parts in cast iron if they broke. I’ve used the technique a long
time ago when I was self educating myself on all the ways to pour
molten metal. Can’t recall the proportions, but you’d want to use the
minimum amout of oil to hold the cement together and…Use it
outdoors or under a good exaust system…lots of smoke. It gives
excellent smooth surfaces because of the fine powder state of the
cement and is reuseable if conditioned. Or you could just order some
relatively inexpensive Petrobond sand from a source like this…
http://budgetcastingsupply.com

Frank Fritzges


#4

The sand used for jewelry casting is actually a mixture of clay and
sand. You can check out Delft clay (expensive) or another sand/clay
mixture or try mixing your own. I’ve even heard of people having
success with fine sand mixed with motor oil. For coarser work such as
is done in iron casting a “green” sand is used. I’ve heard of people
using a fie mixture of that but haven’t tried it myself.

Brian Corll


#5

If you are trying to try this form of casting, Grobet sells prepared
casting sand under the ProCraft name that is ready to go out of the
can (appx 5lb cans). If you want to mix your own, I tripped across
this recipe on another forum:

  Prices shown here is what it cost me (http://www.ray-vin.com
  http://www.ray-vin.com ) to make my first batch. I am not
  selling K-Bond at this time. Density is about.17 lbs per cubic
  inch. One pound is 5.86 cubic inches. My cost per 100 pounds is
  $31.51 not including freight. Ingredents: 100 lbs. sand - 100
  mesh or finer - http://www.u-s-silica.com/US Silica F110 6 lbs.
  Organo-bentone - http://www.rheox.com/Bentone 34 or
  http://www.scprod.com/VG-69 3 lbs. Polybutane (2 US Quarts)
  Indopol L-100 BP Petroleum or

http://chevron.com/prodserv/NewOronite/products/pr_polybutene.htm

  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 -
  http://www.lab-proinc.com/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 http://www.u-s-silica.com/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
  http://www.rheox.com/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.

#6

Hi Scott

For bonded sand, we prefer petrobond. It is available online from
sources like http://www.budgetcastingsupply.com or
http://www.mifco.com .

For simple shapes you might want to look into lost foam casting.
There is an example on my projects page
http://www.granthams.com/Projects .

Lost foam casting only needs silica sand, which is used for
sandblasting and is available at most home centers. Make sure you’re
buying silica sand and not glass beads.

Stay away from play sand, it’s not sharp enough to hold together.

Mixing western or southern bentonite with silca sand is the basis for
green sand, but can be difficult to keep in temper and requires more
venting. It also tends to freeze in cold weather.

Have fun! And feel free to ask questions.

Rod Grantham


#7

Scott

It’s probably best to use a commercial casting (foundry) sand
because of its fine and uniform size, silica sand base, and the
presence of binders (clay, oil, resins) that allow the sand to be
rammed and hold the impression when the pattern is removed without
crumbling. It is possible to use sand moistened with water, but the
water tends to dry quickly, and of course turns to steam when heated.
You can find more on the subject if you search the world
wide web.

Dick Davies
ex foundry buff


#8

I use Delft sand for small 65mm - 110mm dia castings, and find it
excellent, and it lasts quite a while if you’re careful to recover
the unburnt sand. With regard to other sands like Petrobond etc I’d
advise you try before you buy, as maybe there’s a quality difference
to be appreciated. I was teaching at Revere Academy a while ago and
when I had need of a quick casting I used the casting sand that Alan
had there. It seemed like good sand, a little coarser, was the same
colour as Delft. But it was remarkable how it was so less able to
hold together than Delft clay. I couldn’t make it do what I regularly
do with my Delft at home. It made me think that though Delft is
considered pricey it is very good. I’ve done complicated and curvy
part-lines, spent time scraping and tamping, and poured quite
excellent castings.

Plus, here’s another thought. I’ve done delft silver casting with 16
year-olds, and one came to me with a mold saying is this ok? and I
saw that they’d not compressed the sand enough at all. I looked at
the clock and thought we don’t have time to do any better, so I said,
sure fine, let’s go. And it was fine! Remarkably, the Delft held it
together.

Though I have to say I might try the Indian Trick of cement + oil!

Brian

Brian Adam
Auckland NEW ZEALAND
www.adam.co.nz