My good friend Carolyn sent me two wax molds hoping I could use them to create some ceramic tiles. They are wax replicas of 19th century German gingerbread molds and are intended for display only. They are very delicate and certainly not suited to having clay forced into them. But I love a challenge and have found a way to make a sturdy open-faced plaster mold using the wax molds as a starting point.
I decided to tackle the smaller wax mold first. It measures about 1 1/2 inches by 3 1/2 inches and it depicts a bearded Father Christmas character with a pack on his back and a small pine tree in one hand. It is less than 1/2 inch thick and the back surface is very wavy and irregular. Any attempt to press clay into it would surely crack it into pieces. So what I did was create a plaster backing that could withstand the pressing required. IMAGE BELOW
I made a small box by cutting pieces of vinyl tile and taping them together with some masking tape. It would be a tight fit cut to the exact width and length of the wax mold. It was about one and a half inches deep.
I then poured some potter's plaster into the box leaving a 3/4 inch space at the top. Then I quickly pressed the wax mold into the box (image side up) making sure it was level as I pressed it into the plaster. The plaster had the consistency of sour cream and sets up very fast.
About an hour later the plaster had hardened enough for me to carefully cut the blue tape and remove the vinyl sides. Now what I had was a block of plaster with the wax mold embedded into the top surface. I forgot to take a picture of this stage. I let this block dry out (cure) for 3 days before proceeding any further.
I then poured some potter's plaster into the box leaving a 3/4 inch space at the top. Then I quickly pressed the wax mold into the box (image side up) making sure it was level as I pressed it into the plaster. The plaster had the consistency of sour cream and sets up very fast.
About an hour later the plaster had hardened enough for me to carefully cut the blue tape and remove the vinyl sides. Now what I had was a block of plaster with the wax mold embedded into the top surface. I forgot to take a picture of this stage. I let this block dry out (cure) for 3 days before proceeding any further.
ABOVE IMAGE This step wasn't really necessary but I did it to make the finished tile a little bit bigger. I ripped a wooden yardstick on my table saw to get this exact height. Actually I should have made it an 1/8 inch higher instead of flush. I then glued these strips to the plaster block and wrapped it with a rubber band while it cured.
On the next day I coated the top edge of the wood with some paste wax. I then clamped four pieces of PVC around the assembly that were about 3/8 of an inch higher than the wax surface. They were not glued together. (NOTE: the PVC I use is cellular PVC and can be purchased as boards or sheets from lumberyards)
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On the next day I coated the top edge of the wood with some paste wax. I then clamped four pieces of PVC around the assembly that were about 3/8 of an inch higher than the wax surface. They were not glued together. (NOTE: the PVC I use is cellular PVC and can be purchased as boards or sheets from lumberyards)
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I then packed clay into this area and scraped it smooth. IMAGE BELOW
After three hours of drying I removed the clamps and the PVC strips.
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I carefully peal the clay from the wax surface and VOILA! ... the image is revealed!!
IMAGE ABOVE The prototype was about the firmness of American cheese and needed a bit of touching up. His nose was missing and the border needed some help. From this point onward the process is exactly the way I make all of my open faced production molds.
I placed the prototype on a sheet of PVC and and built walls around it using PVC cottles. I then pressed strips of clay around the bottom outside edges to prevent plaster from leaking out. I know that most people press their clay on the inside instead, but my way looks much neater when finished. IMAGE BELOW
I placed the prototype on a sheet of PVC and and built walls around it using PVC cottles. I then pressed strips of clay around the bottom outside edges to prevent plaster from leaking out. I know that most people press their clay on the inside instead, but my way looks much neater when finished. IMAGE BELOW
I then fill the form with plaster and wait about three hours until the plaster hardens and cools down. I make my molds about 3 inches thick. Some people might consider this overkill but I don't want my molds cracking on me. IMAGE BELOW
IMAGE BELOW I remove cottles when cool.
Then I flip the mold over and see the back side of my prototype. IMAGE BELOW.
I pull out the prototype carefully by inserting a putty knife into the clay near the edges all the way around and gently pry out the prototype. The prototype always is mangled in the process. IMAGE BELOW
Success! The mold is finished. I just round off some of the outer edges and set it in front of an electric fan. After about 6 days the plaster will be completely dry and ready to use. These tiles will be a big hit around the Christmas season. On some I will insert small nichrome wire "u's in the top edge. Then I can attach string so they could be hung on a tree.
I will continue this process in the future.
I will continue this process in the future.
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