This is a Pish that was 3D scanned from a small sculpture. It was 3d printed in Polysmooth and then molded using Smooth-on Rebound 25. The support shell was made from Artkast Brushable plastic from Brick in the Yard. The goal is to cast it in bronze using ceramic shell. Next step is slush casting the wax copies and sprueing. Any advice on sprueing is appreciated. Is there a reason why castings aren't sprued on the inside? I understand cutting the sprue could be a problem. Here's the head sprue plan right now. I'm struggling on the tail the best orientation on the tail.
No, first time with bronze and ceramic shell. Each 3d print costs about $25-30 with Polysmooth and takes 2-3 days at 0.2mm. I could do it with PLA which is cheaper per kilo but the post processing take longer. I figured its faster and cheaper to do it with wax if I need more than one. Edit: I also need to chase it before casting. I would have done it in the digital sculpt but my skills with Zbrush are still not there.
I would run something from the "tail" back up to the top of the cup. Nothing wrong with spruing to the inside, but as you said, removing it will be a pain later. Plus, you are not closing up your pigfish, so whatever work you do inside the cavity will show. I like it on the belly where you have it. Mach, preheat your shell to around 1700 and pour bronze in that thing around 2000.
Oh I see it now... You ARE going to close it up. Planning on tig welding front to back half I guess??
I'm planning to tig it closed later. If there's no harm in running it inside, I'll likely sprue it this way.
I would have thought an internal sprue wouldn't be a problem and would save a lot of finishing work (just cut what you can get to off!) Is there a chance the sprue will draw metal and cause a shrink? Jason.David et al are your guys for this one. Loving the 3D model
If you try what you have in post #6, be aware, metal doesn't like to flow uphill. So a vent at the highest point back up to the cup will help it expel air and metal fill it completely. At that point, you are relying on head pressure from gravity to help the metal go uphill. (yeah I know, shell is gas permeable) An extra vent or two back up to the cup, never hurts. See my fox job for spruing internally with a vent just inside the edge. It worked really well. http://forums.thehomefoundry.org/index.php?threads/a-box-of-wax-foxes.281/
Thanks Jason, I looked at your Fox thread and will do the same thing. Had some time to pull the first wax copy. Not too bad. My wax is supposed to be Victory Brown but is very soft. I ordered some AB-150 and square cored sprues from Arizona Sculpture to compare. I'll pull two more copies and then chase them. On the topic of cored sprues, has anyone tried casting the wax around a steel rod and then using a bolt buster to pull the rod out?
Looking good! I thought I demo-ed my hollow wax sprue in a video. No bolt buster needed. I soak my plaster sprue mold in water, shake it out, install a lubed up 3/8" steel bar and pour wax into it. I give it about 5mins and push the rod out. Then it's into the cold water. The hollow sprue practically floats out. I'll see if I can find you a video.
Have you set up the sprue yet?? Could this work? Please excuse the photoshop hack job...it was a quickie. edit: use a cut off saw to cut the sprue flush with the seam.
I haven't sprued it yet so your idea could work. My only limitation is the size of my kiln. I pulled all 3 waxes last weekend and am chasing them now. The RR materials arrived. Pricey stuff.
Lets see some photos. And just don't let the slurry freeze! I'm kinda surprised they mailed it to you this time of year.
cool... I'll film this one. Haven't done lost burnt wood yet. Should work, fingers crossed. It's going to need some kind of coating to keep the slurry from soaking into the wood on the first coat. I'm thinking a thin coating of shellac. That would burn up and not alter dimensions too much. Please start a new thread dedicated to our project. It deserves it and I'm sure the peanut gallery here will find this one interesting. Take plenty of photos and post them in the thread. I'll use them in our video.
Done. I plan on using "duco" cement, as it's cellulose nitrate - and follow up with three coats of shellac, seeing as how I use it a lot. Thread started. Here's to balsa-wood and lathe dogs.
It was shipped after the big freeze a couple of weeks ago but they ship it insulated. The white wrapping is plastic wrapped poly-ethylene insulation. The pack on top is a big handwarmer or the same type of exothermic dry chemical heater. And they put a freeze sticker on it too.
