Hello! I’m struggling to mold a couple of CAD ring patterns I designed that have been successfully cast by shapeways. I imagine they’re printing the design in wax rather than molding a printed part of another substance, and then casting the wax directly. When I mold the master (a bronze cast of my design from shapeways) I have horrible issues getting the wax out without it breaking, as the silicone is in-between all these tiny details that shred the wax as I try to take it out.
I’ve seen equally detailed rings, if not more detailed, be lost-wax cast, and molded, so I’m struggling to believe this pattern is “too complex” to mold. I’m also curious if there’s a best way to cut the silicone in order to get the most optimal injection, as sometimes the mold is mashed due to my removal of the master. (I’m on mold number 3 right now and about to trash it, and I want to stop wasting money.)
I’m using pink wax, the Fuser500 wax injector, and poured silicone molding compound. I’m attaching pictures of the model I’m trying to mold.
Hi,
can you post pics of how you are cutting open your molds?
generally speaking, if the ring/ master was cast from a printed model, there would be less shrinkage than if the master was then molded, a wax shot, and then that wax cast…
my brain is thinking…perhaps…
carefully, safely
cut thru the mold vertically, along the flat side of the ring to open up the mold…your master will be embedded in the rubber…(and no parting lines on the band to clean up/ mess up your pattern)
cut around the interior diameter of the finger hole, in order to release the rubber in the cutouts…this would eventually leave the master/ the wax sitting around a core of rubber that you would eventually pull the master/ the wax off of…
then make release cuts perpendicular/ radially(?) around the outside diameter of the master so that you can fold/ bend back the rubber…the rubber will pull out of the cutouts while the master/ the wax is supported by the core…
hopefully it will not break when you pull it off the rubber core…?
…how thick is the ring…?
julie
I suggest cutting an inner key which will allow an inside strip to be removed from the mold with the wax and then easily peeled out of the interstices.
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A lot of folks think making molds and injecting waxes is easy and sometimes it is. This ring is especially difficult though, which you’re finding out with the little bits of rubber getting stuck in those tiny holes. You have a mixture of wide flat areas, with numerous tiny holes and lots of right angles, which when combined makes for a challenging mold to make and to get successful injected waxes.
I’ve made hundreds of rubber molds in my career and still don’t think that I’m great at it. Just good to pretty good. As Elliot_Nesterman says there are many tricks, like inner keys and removable mold sections.
I don’t have any advice for you, except to suggest sending your ring out to a professional casting and moldmaking company and have a professional mold maker make your rubber mold. It probably won’t cost a lot. Then you can see what they did and you’ll have something to replicate for future objects. Unfortunately, I don’t think there are any good videos or books describing how to cut apart complex rubber molds. That’s why I’m suggesting this idea.
Good luck! I feel your pain!!
Jeff
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Here is a different idea. How about making a master out o sheet metal. You can saw out the hole areas, Have a blank for pressing out blanks made. Actually cheaper and in some ways cheaper.
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All those little holes usually won’t be a problem if you cut a plug. I learned this technique at a seminar put on by Romanoff. It changed my life. I have shown this technique to other jewelers when I visited. They immediately start cutting plugs in their molds. From time to time I will cut a plug in a mold I made years ago before I knew the technique. This is similar to the way Elliot showed. The wax in the picture pulls right out with all of the holes open if you use the right pressure on the injector. If anyone is interested, I will do a complete write up on how to do it.
Dave
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Hi,
ah yes, i failed to mention the cross cuts…hmmm…
julie
