After you have found or sculpted a suitable form for your sand resin mold, its time to actually start making the mold. For my piece i am making a simple two part mold that will divide the object into two halves. You will first start by burying one half (or section depending on how many parts your mold requires) in packed sand leaving the other half exposed. after mixing up the resin, carefully pack it on top of the mold making sure to not shift the sand underneath. To create a perfect box like mold the easiest way to go about this is to simply make a box form out of wood for the resin to rest in as it cures. Once you're done packing, leave the mold alone for 24 hours before removing and repeating on the other side.
Making the Mold
The image below shows an industrial Sand-Resin mixer used when making many molds, this is a bit excessive for our purposes so only mix up what you are going to use.
The image below is a good example of a two part mold, which is what is being made in this step only with sand resin rather than plaster.
Note: Be sure to only keep the section that is currently being coated in resin exposed, this is especially important when making a mold with multiple parts. Also remember to use a respirator as resin is toxic. Also adding a pigment, like red iron oxide to the sand mixture when mixing makes it easier to tell when the resin and sand is evenly mixed together and ready for packing.