Looks like extending the template by a couple of tabs that can be pinched together will make extraction much easier. That way the print warps inwards and away from the plaster for easy release.
I'd thought about something that stuck up, but then it couldn't be printed flat on the bed. The thing that is really preventing flexing is the curvature of the handle itself.
@@PotterybyKent mhm okay. In that case, maybe holes for dowel pins or wood screws could do the trick. Have you considered finishing the surface with filler, sanding and spray coating with lacquer?
I was going to add some screw bosses to hold it down to the bottom plate if plaster was leaking. Those could serve the double purpose of points to pull on. However the tape worked well enough so I left them out. As far as finishing the surface, yes I have several other videos showing how to smooth the surface. However for this handle it wasn't really needed. You already need to clean the (small) seam line so most of the handle is gone over in that process. Also by the time it transfers to plaster then to slip and then fired (and shrinks), and with glaze, pretty much most of the artifacts from printing go away.
@@PotterybyKentYou could have the handle part actually go past the bottom plate instead of stopping on it. Have some key holes that are open on the side that protrudes past the plate. Then you slide into these holes 3D printed keys that have a slight taper along the length so it’s actually a wedge. Think of how some old tables are held together with nothing but wedge pins. This would hold the handle part in tight, have more to grab from when removing, allow to be printed flat, and no need to use tape. Just slide out the keys and it should all easily separate.
@chadvoller Thanks! I was considering something like that - in particular as a way to not need the tape. However the other consideration is so plaster doesn't leak and I think the jog in the bottom is actually helping in this case. I could put that geometry in the handle part but that would increase the thickness.
Have you considered adding bosses to the inner part of your mold with heat inserts so you could use eye bolts etc. for easier grip? If this hasn’t been suggested.
I don't think I'd add heat set inserts. Some bosses might work though - the real trick is keeping it flexible, so I'm not sure how much they'd help vs pulling on the edges.
Don’t forget to score the ends of that handle and the pot where you want to attach the two pieces. The slip really doesn’t stick all that well to a smooth surface. But, if you score the handle and the mug, before adding the slip, it will make it that much more stable.
I haven't found that to be the case with the slip I'm adding, the moisture content, and proper drying. However if you've had issues or are concerned at all, it isn't a bad practice. For thrown pots and pulled handles it is very much a good idea since it reorients the clay particles.
The draft angle is what made the piece release with this iteration, they're absolutely necessary for casting like this as well as injection moulding. Also, if you take something like a palm sander and just touch it to the side of the mould with the fresh plaster, it'll vibrate all of those bubbles out immediately. Works for cement as well, that's ehat I usually do.
It very much is not only the draft angle as I had them in some of my previous iterations. This is different than injection molding because the plaster actually grows slightly. And yes there are several ways to help knock out the bubbles however with such a small mold I didn't have any issues here.
I have not, but others have. It does work, but then the print is destroyed so it can't be reused. So it's really a tradeoff - if printing is easy for you and you can just reprint another. Then it would be less fiddly to get out with some heat, but it also works with just a bit of patience and persistence and can be reused in that case.
If you print a pin or two in the cavity of the handle you might be able to remove it without having the pliers touchthe plaster edge (or its only me that would risk messing the edge up)
There's enough space to grab on without touching the plaster, but not a lot! I think there is some room for optimization here, but it is also good enough to make useful molds. I've had several other people successfully make them at this point which is always fun to see!
Hi Kent! Your video showed up in my recommendations and I watched it because I recently made a metal mug with a handle. I don't know anything about slip casting, but I recommend watching the video "Print-Wave Metal Casting". Even though it's about metal melting, people have commented that it would be also great for slip casting. Cheers!
You might want to look at the PrintWave technique used for making plaster molds for metal casting, as it solves a very similar problem. The key steps boil down to heating the plastic mold to the point where it becomes soft and can be removed easily, as well as using the build plate of the 3d printer itself as the parting line/mold bottom. While this method does destroy the plastic mold, these are usually just a thin light shell so it will probably still be a lot more economical than the added design effort of a multi-part mold, and does not limit the design (no undercuts or anything required)
Thanks. I'll need to take a look. But I've ver deliberately been looking at a process where the molds can be reused many times. Also, since the clay needs to be removed once slip cast, undercuts are still a fundamental issue.
Nice video! Still I don't understand why you didn't use just 3d printed mold to cast directly. I do understand for other materials like resin or metal, where you just can't, but slip casting I saw lots of 3d printed molds.
Maybe it would be easier getting the plastic handles out of the mold if you add a couple of grip points on the insides. Like, just a nub or something that you could grab with the needle nose pliers.
I thought this too! inside the spur cups of the handle model you could put a rib across it, something you can grab with a pair of needle nose, since it's a little tough to get out with the fingers.
You wouldn't want a rib that spanned side to side as that would limit flexibility. What comes to mind would be pairs of horizontal tabs with a hole for something like snap ring pliers to get into. That would let you pull the walls together slightly. The downside of this is that this inner mold is printed rather thin so it can flex, and therefore those tabs might break easily (and adding reinforcement is counter productive given the need to flex). And it would likely require a new tool. For those who already bought the molds, I'd love feedback on this aspect of the design.
Most people can't print TPU easily and the surface finish is way worse which is a problem since it transfers into the pot eventually. My last couple videos (and the comments) go through a lot of the tradeoffs and considerations if you're curious.
It's mostly about tradeoffs, your process and your logo. Currently I'm using an underglaze stamp I made (I 3d printed a mold and poured silicone in it). I've also used a 3D printed stamp to make an impression but my slip casting clay body isn't very plastic so getting the timing right was tricky and why I switched. I do use it on my thrown pots. I have videos on my channel for both. I have yet to cast in my logo - I think doing so would require a much larger logo than I'm currently using since plaster is pretty delicate. It is something I want to explore.
@@PotterybyKent just tried to make a casting with the logo into a single non-collapsible shape and the results are always different, so today I will print an blank mug and a separate stamp. Thanks for the answer!
You mean create a mold with the handle attached to the body already? There are several reasons. One is this allows you to mix and match. However more fundamentally, I've seen very few slip casting molds with handles integrated. My guess is that the shrinkage of the clay might cause it to get stuck around the plaster for handle if you aren't careful about clay body selection and design of the forms.
@@PotterybyKent The advantage of a little shake table would be that you could run multiple molds at the same time! Since you need at least 2 molds per handle AND you could use it for any of the molds you make in the future.
Instead of using PLA... you should try printing with PETG filament. PETG is a lot more flexible than PLA, and with thin walls like that it is nearly indestructible. Thin wall PLA tends to crack at the layer lines when you flex it too much.
If you don't care about reusing the 3d print, consider the method used here where he casts directly on the printer bed, and uses a microwave to soften the plastic plug before removing it. ua-cam.com/video/0kxfDN4cKTk/v-deo.html
Unlike metal casting the plaster is actually reused many many times (maybe 50) to make pots. And reuse of the 3d print is also an explicit design goal as well. In fact production potters will actually invest in silicone molds so they can make many paster molds to scale up production. By reusing the 3D print, that is no longer needed.
@@PotterybyKent Didn't mean it to in any way detract for the work you are doing. I have experience with plaster slip casting molds, and I believe you did an excellent job of designing your mold for reuse, and the design process you followed was great with the taper needed to remove the 3d print also needed to remove the slip casting. Where the other method seemed to be relevant was the lower quantity of plastic needed, faster 3d print times, and the use of heat to ensure the plastic was softened to enable easy extraction from the mold. But, It obviously has the negative of not being reusable. I am curious how reusable the 3d prints end up being, and if another material like TPU might make them easier to extract.
No worries. I suspect it wouldn't take many reuses to make up for destroying the mold, and here you need 2 per handle. As far as TPU, the problem there is the surface finish (and it being tricky to print doesn't help others using these molds as well). It actually isn't that hard to extract - just takes a bit of patience.
Finally, it happened, congratulations! It turned out to be a great job.
Yes! Thank you!
Thank you for sharing your 3d print mold making journey!
Thanks for following along!
Looks like extending the template by a couple of tabs that can be pinched together will make extraction much easier.
That way the print warps inwards and away from the plaster for easy release.
I'd thought about something that stuck up, but then it couldn't be printed flat on the bed. The thing that is really preventing flexing is the curvature of the handle itself.
@@PotterybyKent mhm okay. In that case, maybe holes for dowel pins or wood screws could do the trick.
Have you considered finishing the surface with filler, sanding and spray coating with lacquer?
I was going to add some screw bosses to hold it down to the bottom plate if plaster was leaking. Those could serve the double purpose of points to pull on. However the tape worked well enough so I left them out.
As far as finishing the surface, yes I have several other videos showing how to smooth the surface. However for this handle it wasn't really needed. You already need to clean the (small) seam line so most of the handle is gone over in that process. Also by the time it transfers to plaster then to slip and then fired (and shrinks), and with glaze, pretty much most of the artifacts from printing go away.
@@PotterybyKentYou could have the handle part actually go past the bottom plate instead of stopping on it. Have some key holes that are open on the side that protrudes past the plate. Then you slide into these holes 3D printed keys that have a slight taper along the length so it’s actually a wedge. Think of how some old tables are held together with nothing but wedge pins. This would hold the handle part in tight, have more to grab from when removing, allow to be printed flat, and no need to use tape. Just slide out the keys and it should all easily separate.
@chadvoller Thanks! I was considering something like that - in particular as a way to not need the tape. However the other consideration is so plaster doesn't leak and I think the jog in the bottom is actually helping in this case. I could put that geometry in the handle part but that would increase the thickness.
Wow you did it 🎉 That was really tricky !
Yes it's working great now!
Extremely informative! Thank you so much for sharing your knowledge🙏🏽✌🏽
Thanks! Glad it was helpful.
Have you considered adding bosses to the inner part of your mold with heat inserts so you could use eye bolts etc. for easier grip? If this hasn’t been suggested.
I don't think I'd add heat set inserts. Some bosses might work though - the real trick is keeping it flexible, so I'm not sure how much they'd help vs pulling on the edges.
Don’t forget to score the ends of that handle and the pot where you want to attach the two pieces. The slip really doesn’t stick all that well to a smooth surface. But, if you score the handle and the mug, before adding the slip, it will make it that much more stable.
I haven't found that to be the case with the slip I'm adding, the moisture content, and proper drying. However if you've had issues or are concerned at all, it isn't a bad practice. For thrown pots and pulled handles it is very much a good idea since it reorients the clay particles.
@@PotterybyKentthank you for your response. I really enjoy your channel!
@@Heartwing37 Thanks so much!
The draft angle is what made the piece release with this iteration, they're absolutely necessary for casting like this as well as injection moulding. Also, if you take something like a palm sander and just touch it to the side of the mould with the fresh plaster, it'll vibrate all of those bubbles out immediately. Works for cement as well, that's ehat I usually do.
It very much is not only the draft angle as I had them in some of my previous iterations. This is different than injection molding because the plaster actually grows slightly. And yes there are several ways to help knock out the bubbles however with such a small mold I didn't have any issues here.
Nice process, have you tried a hot air gun to remove the print?
I have not, but others have. It does work, but then the print is destroyed so it can't be reused. So it's really a tradeoff - if printing is easy for you and you can just reprint another. Then it would be less fiddly to get out with some heat, but it also works with just a bit of patience and persistence and can be reused in that case.
If you print a pin or two in the cavity of the handle you might be able to remove it without having the pliers touchthe plaster edge (or its only me that would risk messing the edge up)
There's enough space to grab on without touching the plaster, but not a lot! I think there is some room for optimization here, but it is also good enough to make useful molds. I've had several other people successfully make them at this point which is always fun to see!
Nice iteration- big progress over the last few weeks. One note: this kind of fillet doesn't have a silent "t".
Thanks!
I'd like to know the etymology there. I know it's derived from latin / old French but not sure when the sound changed in this context.
Hi Kent! Your video showed up in my recommendations and I watched it because I recently made a metal mug with a handle. I don't know anything about slip casting, but I recommend watching the video "Print-Wave Metal Casting". Even though it's about metal melting, people have commented that it would be also great for slip casting. Cheers!
Thanks!
You might want to look at the PrintWave technique used for making plaster molds for metal casting, as it solves a very similar problem.
The key steps boil down to heating the plastic mold to the point where it becomes soft and can be removed easily, as well as using the build plate of the 3d printer itself as the parting line/mold bottom.
While this method does destroy the plastic mold, these are usually just a thin light shell so it will probably still be a lot more economical than the added design effort of a multi-part mold, and does not limit the design (no undercuts or anything required)
Thanks. I'll need to take a look. But I've ver deliberately been looking at a process where the molds can be reused many times. Also, since the clay needs to be removed once slip cast, undercuts are still a fundamental issue.
Nice video! Still I don't understand why you didn't use just 3d printed mold to cast directly. I do understand for other materials like resin or metal, where you just can't, but slip casting I saw lots of 3d printed molds.
Because the plaster is specially designed to absorb water from the slip to form the solid clay. That moment of water is a key part of slip casting.
Maybe it would be easier getting the plastic handles out of the mold if you add a couple of grip points on the insides. Like, just a nub or something that you could grab with the needle nose pliers.
That is an interesting thought!
I thought this too! inside the spur cups of the handle model you could put a rib across it, something you can grab with a pair of needle nose, since it's a little tough to get out with the fingers.
You wouldn't want a rib that spanned side to side as that would limit flexibility. What comes to mind would be pairs of horizontal tabs with a hole for something like snap ring pliers to get into. That would let you pull the walls together slightly. The downside of this is that this inner mold is printed rather thin so it can flex, and therefore those tabs might break easily (and adding reinforcement is counter productive given the need to flex). And it would likely require a new tool. For those who already bought the molds, I'd love feedback on this aspect of the design.
@@PotterybyKent Those are good points, makes sense that you want the plastic to flex and not the plaster. What about something like printing TPU?
Most people can't print TPU easily and the surface finish is way worse which is a problem since it transfers into the pot eventually. My last couple videos (and the comments) go through a lot of the tradeoffs and considerations if you're curious.
perfect work
Thanks a lot!
Hi Kent, what's the best way to make a logo? To cast or make a stamp after taking it out of the mold?
It's mostly about tradeoffs, your process and your logo. Currently I'm using an underglaze stamp I made (I 3d printed a mold and poured silicone in it). I've also used a 3D printed stamp to make an impression but my slip casting clay body isn't very plastic so getting the timing right was tricky and why I switched. I do use it on my thrown pots. I have videos on my channel for both. I have yet to cast in my logo - I think doing so would require a much larger logo than I'm currently using since plaster is pretty delicate. It is something I want to explore.
@@PotterybyKent just tried to make a casting with the logo into a single non-collapsible shape and the results are always different, so today I will print an blank mug and a separate stamp. Thanks for the answer!
Happy to help!
Why not just attach them to the mug when creatinga 3d print?
You mean create a mold with the handle attached to the body already? There are several reasons. One is this allows you to mix and match. However more fundamentally, I've seen very few slip casting molds with handles integrated. My guess is that the shrinkage of the clay might cause it to get stuck around the plaster for handle if you aren't careful about clay body selection and design of the forms.
@@PotterybyKent Thank you for the info! Very helpful
Next up: 3D print a little shake table to help remove the bubbles from the molds!
I actually did have an idea here! But it's not a table - something to clip onto the mold itself.
@@PotterybyKent The advantage of a little shake table would be that you could run multiple molds at the same time! Since you need at least 2 molds per handle AND you could use it for any of the molds you make in the future.
I actually have a pretty big shaker table. However most people using Shape Cast don't so I've tried to show practices that everyone can use easily.
Are you selling these molds? Or are you making them for personal use?
I am selling them (and also using them myself!). shapecastmolds.com
@@PotterybyKentthank you! Buy some now…
@@Heartwing37 Great!
Instead of using PLA... you should try printing with PETG filament. PETG is a lot more flexible than PLA, and with thin walls like that it is nearly indestructible. Thin wall PLA tends to crack at the layer lines when you flex it too much.
Yes you probably could. The nice thing is if it's working with PLA it'll likely work with many things.
Супер гуд!
Thanks!
One-word -
release agent
Not needed luckily!
Take a heat gun and soften the PLA to get the 3D print out.
Yes, others have used that approach to destructively remove the print. Luckily by just being careful pulling it out it can be reused.
If you don't care about reusing the 3d print, consider the method used here where he casts directly on the printer bed, and uses a microwave to soften the plastic plug before removing it. ua-cam.com/video/0kxfDN4cKTk/v-deo.html
Unlike metal casting the plaster is actually reused many many times (maybe 50) to make pots. And reuse of the 3d print is also an explicit design goal as well. In fact production potters will actually invest in silicone molds so they can make many paster molds to scale up production. By reusing the 3D print, that is no longer needed.
@@PotterybyKent Didn't mean it to in any way detract for the work you are doing. I have experience with plaster slip casting molds, and I believe you did an excellent job of designing your mold for reuse, and the design process you followed was great with the taper needed to remove the 3d print also needed to remove the slip casting.
Where the other method seemed to be relevant was the lower quantity of plastic needed, faster 3d print times, and the use of heat to ensure the plastic was softened to enable easy extraction from the mold.
But, It obviously has the negative of not being reusable. I am curious how reusable the 3d prints end up being, and if another material like TPU might make them easier to extract.
No worries. I suspect it wouldn't take many reuses to make up for destroying the mold, and here you need 2 per handle. As far as TPU, the problem there is the surface finish (and it being tricky to print doesn't help others using these molds as well). It actually isn't that hard to extract - just takes a bit of patience.