Galaxy Reaper II: A Technical Review
A majority of my work are smaller solid resin casted pieces. I start by reusing an existing part, make an original sculpt or kit-bash something that is a combination of those sources. The next step is to make molds of the parts.
Vaccum Chamber and pump.
Mold form with part to be molded attached to venting stems.
I use a vacuum chamber and pump to degas uncured silicone. This process will reduce air trapped in silicone, which can cause bubbles that get trapped on the surface area of the part to be molded. If bubbles surround the part to be molded, the result will be an unwanted void in the mold that will fill with uncured resin, leaving an unwanted blemish on casted parts. Although, the blemish could be removed from the casted part, degassing the silicone will save time and make for cleaner casts. The photo on the right shows a part being molded. I also use a technique of pouring silicone that allows the part to be lightly coated with silicone before pouring the bulk of the silicone in the form. This allows any further bubbles to move away from the surface area of the part.
The above images are of some two-part molds for casting needed parts.
I use a pressure pot when casting the resin parts. Once a mold is filled with uncured resin, the mold is sealed into the pressure pot. When the resin is placed under pressure, air bubbles in the resin are forced out of the mold thru the mold's sprue vents. When making molds, consideration should be given to how resin and air bubbles may travel thru the mold. The part to be casted should be placed into the mold form so that no air may become trapped and therefore not allowing resin to fill in the mold properly. Sprue vents will help for proper air and resin flow and can be beneficial with troublesome areas where air can get trapped.
Solid resin casted parts work well for small parts and in some cases larger pieces, if weight is not a concern. I wanted to make larger scale pieces but the costs of materials and the cost of shipping heavy completed works to galleries and patrons was a concern. I decided for the larger scale pieces, I would use a hollow casting process. For hollow casts, I use Smooth-On 65D which is a lighter weight resin that cures quickly. My first attempt at hollow casting was a slush-cast method. Slush-casting consists of shaking the sealed, partially resin filled mold in a vigorous manner allowing the resin to fill-in the outer most areas of the mold cavity. This often results in resin not being distributed within the mold properly causing the hollow casted piece to have weaker areas in the walls of the cast. For proper hollow casting a roto-casting device is beneficial.
3D printed bushings for roto-casting machine.
Testing the roto-casting machine movement.
To move forward with the hollow casting, I built a roto-casting machine. The device was made from wood, PVC pipe, peg board and 3D printed parts.
Partially resin-filled mold is secured on movable platform of roto-casting device. The movable platform allows for adjusting the molds placement to find the best center of gravity.
Hollow roto-casted part and mold.
The roto-casting machine allowed me to make larger scale pieces such as the "Galaxy Reaper II" as seen above. The "Galaxy Reaper II" is a mix of hollow roto-casted and solid pressure casted parts that stands approximately 12 inches tall. The "Galaxy Reaper II" was submitted for a group Art Toy show at the Clutter Art Gallery in Beacon, New York.
The second test of the roto-casting machine was in producing the "One Eyed Kaiju" figures as seen in the image above. For more details about the "One Eyed Kaiju's" development, click on the image.
The roto-casting machine was also used to make the first piece in the "McManifest Distiney" series as seen above. This multiple piece work was also submitted to a group Art Toy show at the Clutter Art Gallery in Beacon, New York.