Hi, I was wondering, when you do a 3D print with the intention of casting it, what % infill has been working for you? I believe some people have been trying with only shells of PLA but I am concerned it would not be robust enough to add a plaster or ceramic shell? Thanks Andy
Usually 1 shell and 20% infill. Some models i have to use 2 shells on because of holes in the print though.
I do large prints with 0.8 nozzle. Generally 2, sometimes 3 shells. Typically 5-10% infill. My printer will not reliably make a solid print with 1 shell. My top surfaces, if large, need 3 layers to bridge the low infill.
I built my own Delta. Nothing fancy, not horribly fast, but will print for days on end without a hiccup. Uses a Wifi Duet (which is awesome). It will print about 24" diameter and 30" tall.
I’m not much for pictures (of my stuff, keep y'alls coming!), but these are from last night. Water fitting was printed in two parts and hot glued together. That did not work well as the parting line actually has a through gap in it. The part has an internal baffle which is why I printed it that way. I cleaned it up enough to clearly see the failure and test fit. May just weld it up. Other parts are axle bearing caps for a transaxle. I am working my way up to being able to cast a transaxle. Edit: Am re-printing the water fitting in one piece and at a higher resolution (.2mm instead of .4). Also add some sacrificial bits on end of the hose fittings so vents don't muckup the edges.
If you disable the collision detection in cura you can place the models to be printed touching each other. The printer will print them together and they come out as one solid piece that doesn't need to be fused afterwards. That removes the parting line issue. Pretty nice parts. Very good finish on them. What shell material did you use to burn them out?
I used Casting POP (from local ceramic supplier) & mason sand. Chicken wire to hold it all together. 2:1 by volume. Burned out to 1050. Poured them at 900. Am still experimenting. 325 mesh sand is useless. 200 works but cracks horribly. Local supplier has been out of 85 but says it will be in next week. The mason sand is a real mix of sizes. And it’s more shards than grains. Held together well enough that it probably did not need the chicken wire. I mix it pretty soupy.
I've heard POP coats work best if you paint them on in thin layers and build it up. If you do 1 thick coating it tends to crack because the material is uniform and the cracks can propagate more easily.
This one definitely would as it has some flaws. Have decided to re-print/re-cast rather than weld it up. I have re-printed all 4 fittings in a different orientation so they could be printed in one piece. We've had torrential down pours here (Dallas area) on/off for the last week or so. Hoping for Fri/Sat to invest/cast these. I am planning on sealing them using Sodium Silicate to prevent weeping, although this is for a race car, so I can't really say I give a darn if they weep a bit.
