Mold Mix 6 User’s Guide


Simple Steps to achieve a perfect Zircar Mold Mix 6 Mold for:

Kiln Cast Glass

Hot Cast Glass

Bronze Casting



By Leslie Rowe-Israelson and Melanie Rowe




Mold Mix 6 is an excellent, lightweight mold material for casting glass and bronze.  It is fibrous mold material which allows the mold to breathe and when applied thinly-will allow glass to shrink without loosing fragile points, and helps with three-dimensional designs.  Yes it has its limitations, as all materials do-but with these simple steps-we will try to walk you through the application process.


A.  Mixing: Purchased in gallon containers

-         Most important information: Do not add water or let air get to the product.  Keep airtight.

-         Scoop out small amounts of mold material and put in Ziploc containers and Zip bags.

-         Take Braun hand mixer (or equivalent) and whiz mold material till all limps are broken down.  You want these fibers in your mold to weave a blanket mold.  The consistency should be thick cream.

-         It will solidify if it sits for a while after mixing.  Don’t worry-just take a spoon and mix again in small container.

-         Once again, keep lid on even when applying material.


B.     Applying Mold Material for “wax positive”

-         Take small container of pre-mixed Mold Mix 6 and paint on in thin layers with a soft supple brush.  The finish on wax positive will determine finish on art piece.  If the mold material wants to separate- don’t worry, just keep brushing gently.  Start at top and move down project.

-         Place in front of Cold fan to dry quickly.

-         Try to paint each layer in a different direction to almost weave a blanket over wax and use the fibers in the mold material.  These strengthen mold and also helps the mold to breathe.

-         Layer must be tacky dry before applying the next coat.  “Think of drying from inside-out”.  If you try to apply to thick-it will want to crack.  An even coat is the Key.  A fellow shared a great idea of putting a tiny drop of food color while mixing.  I have not tried it yet.  Sounds good though.  Do not let it build up thick in undercuts.

-         Keep painting on layers until you are approximately 1/8 to 1/16th inch thick.  Any thicker and it may not allow sharp areas to shrink, and it may break off arms or fingers OOOCHHH!

-         Let dry totally-approximately 3 days.  If it is still cool to touch wait patiently 2 days for small projects.


C.    Applying to plastercine (no burn-out necessary)

-         Paint on thin layer of Murphy’s Oil use soft brush.

-         Let dry totally.

-         Paint on another thin layer.

-         It will start to curl on the edges.  This is OK.  If you have no undercuts-it should pop-off mold, and you can start again.


D.     Burning-out Mold

-         Microcrystaline wax is toxic when heated to burning state. 

-         When burning out mold with Tiger Torch wear respirator and take all precautions necessary…have fire gloves, eye protection etc ready.

-         Get a metal garbage can (have lid ready to put out fire if it happens to catch the wax on fire).

-         Fill can ½ ways with water-place steel rack on top-place piece on top of rack.

-         Light torch, put torch on low and point to the bottom edge of mold, waving slowly.  Work form the bottom to the top.  Keep torch horizontal at all times.  Do not point into can.  Let it begin to drip slowly-but be cautious of wax catching on fire.

-         If wax starts on fire, stop torching and let the fire drip into the water until it stops.

-         Do not rush and do not worry if mold catches fire-because it will-Make sure you are wearing your respirator.

-         Burn out side with soft wind blowing.

-         Believe it or not, if wax leaches through mold material, it will burn off, Trust me.

-         Now the mold is VERY FRAGILE-be careful.

-         Take the mold and gently put in kiln-and heat up to 1400 degrees F to return the mold to white.  It will not thermal shock-so go as quickly as the kiln will allow.


E.     Release Agents

-         Boron Nitride Boron Nitride Coating Type RS-BNCoat is a high temperature, anti-stick release agent/lubricant. Available in Paint or Aerosol spray can.

-         Coates the surface with out depositing material.

-         Or Bullseye Shelf Primer.  It is a wonderful release that will give you a soft stain finish to the glass wherever it touches the mold.

-         Get a sifter and two buckets.

-         Make sure the mold is clean and all frilly cling-ons are sanded off (vacuum mold carefully and wear respirator as it is carcinogenic in powder form).

-         Get a partner to help, and a large bucket ready to pour shelf primer into.

-         Mix 1 part of powder to 5 parts of water.

-         Mix well, then sift 5 times getting rid of chunks and foreign objects.

-         And quickly after the last sifting (do not let the shelf primer settle) hold the mold upside down, and pour in VERY QUICKLY AND POUR IT OUT EVEN FASTER.  Do not let it settle.  You want the thinnest coat.  If you have-You especially do not want to go slowly if you have any bas relief or fine detail. 

-         Once this has been achieved put the mold back into the kiln and heat to 400 degrees F to burn off all the moisture.

-         You are now ready to load.


F.  Loading Mold

-         Our containment walls of choice are stainless steels tubes and or pots-steel tubs tend to break down at high temperatures and pits into the mold.  I have also just filled the bottom of one of my kilns with sand, but I recommend air to circulate around the containment mold.

-         Select a container that completely surrounds the mold evenly.

-         DO NOT LOAD SAND WITHOUT USING A RESPIRATOR.  Lung diseases are not accepted as a part of our art.

-         Get Dry 80-grit clean silica sand or olivine sand-we burn out our sand before first use to eliminate ant foreign contaminants.

-         Gently cover top of mold to ensure that no sand gets in.

-         Pour sand carefully and slowly into the container, try to match the container with the shape of the mold so that the sand walls are consistent.


G.  Choosing Attached Sprue or Drip pot

-         I believe this is your decision as each project comes with its own technical difficulties.  You must think ahead while designing your sculpture.

-         Will the glass flow into every space?

-         Do I lay the pieces sideways, straight up or down?

-         If I use a ceramic drip pot, I will surely capture bubbles as the glass drips down?

-         Do I gently pour frit into my mold?  Will I hit fragile points?

-         All of these questions must be addressed before beginning the design process.


H.  Firing Schedule – a fine science      

-         This will depend on your piece.  You must do much studying before you begin, but here are a few ideas.

-         Take 10 hours up to 1010 F.

-         Hold 4 hours to heat sink sand & glass.

-         2 hours up to melting temperature.

-         Hold no more than 2 ¼ hours.  Open face only 1 ½ (crystal flows faster than Bullseye.  Frit must be ½ longer)

-         If intricate, narrow spaces-hold 2 ½ hours to 3 hours.

-         Then continue rest of program.