Here’s what happens to the sculpt after I get it.
I make a negative mold of the sculpt with which to make multiple sculpt copies. These Will be used to make plaster slip molds. The plaster slip molds will go to our ceramicist for mug creation.
Here’s the first batch of pictures:
After creating a mold box ¾” larger than the sculpt (in each direction) out of art board and hot glue. I’ll pour each half of the mold separately. To masque out 3-d areas for where I don’t want the polyurethane to go, I use modeling clay:
To help keep the two halves of the mold together, I make impressions for use as a key to align. Here you can see a closeup of one in the clay masque.
So, how to find out how much of the casting material you’ll need? I use rice to approximate the volume.
Now it’s full.
And now it’s measured.
After the rice is removed the whole thing gets sprayed with Tap Plastics Mold Release.
The Materials: Polyurethane Casting Resin system from Tap Plastics.
I mix half the measure of each of the 2-part polyurethane and mix like ‘taint no mixing been done.
The trick is to scrape the sides and the bottom of the container with something square. I use chopsticks. Next, I pour evenly and slowly into a corner of the box. I let the material slowly seep around and up the sculpt. As it’s pouring I notice how like a chocolate bar it looks. Here see it filling in the keys – caramel spilling into chocolate caverns surrounded by creamy white nougat:
Delicious caramel will be the last breath of this tiki mug!
Almost there:
The complete pour.
Once a day has passed, it is safe to attempt the other half. It takes a couple more than a few days to fully cure. I take off the bottom of the mold and flip ‘er over. All that clay we put in has to come out.
The same process is repeated (It usually happens that the rest of the containers are the perfect amount of material) on the back. Mold release, mix half of each, pouring into the corner:
Slowly to the top it pours.
This is the End product. 2 Halves which allows us to make copies of the scupt to use and not have to suffer a meltdown if it becomes damaged. We can just make another. And another. And another.
Next update coming when I get the pics prepared!
This is great, Cute! Is the final mold solid? What is the original made of (the creamy white part)?
Also, I’m not sure what you mean by plaster slip molds. Isn’t the polyeurethane mold sufficient for slip form? I’ve never done it, so pardon my ignorance.
I’m sorry you’re leaving LJ. I always look forward to your posts. But perhaps I’m one of the “poor souls” you’re trying to avoid.
Whatever! I still love ya!
Smooches!
Gee, those are nice pics, I wonder who took them….:P
Oh, I took all these pictures. Especially the ones with me in them. I took those twice.
I don’t want to avoid anyone on LJ, just felt better that people don’t get to read me ‘by default’ unless they do some work. 🙂
Why the masqueing? To avoi damamging the orginal when you take off the polyu?
The masque is for the clay to “make” the other half of the mold. They modeling clay is a stand-in for 1/2 the mold so I can pour the first half. The clay you see on the sculpt is an after-addition to build-up the model to be better suited for this kind of mold. You have to make sure that there are no “under cuts.” That is, areas of the sculpt that would “lock” it into place in the mold. The topology of the 1/2 must always reduce the further you go back to keep this from happening.
That said, the mold still sticks. 🙂