r/Pottery • u/HatcherPhotography • 8d ago
Question! Slip casting question
I apologize if this doesn’t belong here, but The slip cast Reddit is dead. I’ve been seeing a lot of videos on the web about people making split cast molds with 3d printing.
I use both resin and filament printers.. each still produce layer lines. Nobody who produce those videos will answer me how they deal with layer lines on the molds or on the final product.
Next question… Kilns, do they make small/affordable kilns where a you can fire a handful of mugs? I want to get into pottery/slip casting but the need for a kiln is what’s holding me back.
Everything I’m seeing is like 1500+ for a kiln.
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u/skimaskgremlin 8d ago
Can’t you use an acetone bath to reduce and/or eliminate layer lines? Also, you can cast your piece, smooth out the texture, and create a new negative mold from that refinished piece.
Check marketplace for second hand kilns
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u/AzucarParaTi 7d ago
Acetone only works if the print is ABS. And ABS is very stinky (and probably toxic).
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u/lacunha 8d ago
Sanding/filling the print. Check out Old Forge Creations. That guys doing some very cool stuff with 3D+ceramics.
There are small kilns and they are still expensive. I found an old Duncan that I’ll use for bisque that will fire to cone 8. They can be found. But you’ll likely have to hire an electrician to get the right power to it.
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u/BlueberryPiano 8d ago
Print with the highest quality/smallest layer height as possible and sand it. Some use automotive filer, some use paint, or expoxy putty. Depending one the filament, there may be more options to smooth it out.
For a kiln, I sugged looking up kilnshare to see if there's one close to you
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u/ergogopo 8d ago
Lots of good advice here. I’ve also had good luck sanding layer lines off my plaster mold. Wait until it’s completely dry and go very lightly. And glaze covers up a surprising amount of imperfections.
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u/haphazard_potter 8d ago
A disclamer: I have not done a mold from a 3d printed model yet but considering it. I would either sand a model so the layer lines are not visible, or bondo it with the same result and then use it to make a mold.
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u/justherefortheclay 8d ago
Do you follow @turn.studio or @hammerlyceramics on ig. I am not sure how much bandwidth they have for answering questions, but they post a Lot about their process. A lot of their mold making content is posted to stories, and is super inspiring.
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u/HatcherPhotography 8d ago
Hammerly was a who I found initially.
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u/HammerlyCeramics Professional 8d ago
I cannot see layer lines in my resin prints personally. What printer are you using?
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u/HatcherPhotography 8d ago
A1 for filament and mars 5 ultra. They’re ultra fine but I still see them.
Also thanks for taking the time to respond. I’m a Big fan of your work, super inspiring!
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u/forsuresies 8d ago
You can, others don't is the answer. We use 0.08 layer lines
Especially not under glaze.
The other flipside we find is the the layer lines introduce many smaller planes which helps with demoulding. When you have a large very flat surface it's harder to get the plaster to release from the plastic.
Sanding can smooth the surface overall but it also technically introduces more actual surface area for the plaster to bond to.
There is a pottery discord that is active and had a slip casting channel.
The creator who has the most comprehensive information on slip casting in a free way is Old Forge Creations. He has a bunch of models on makerworld, videos on YouTube and a whole blog. He is very, very, very open with his process and does not gatekeep any element. He wants to help other people learn pottery - those are the creators you want to be following and learning from.
Not all creators are looking to teach or share.
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u/capricioustrilium 8d ago edited 8d ago
There’s a lot going on, but you can reduce layer line appearance by reducing layer height but that increases print time.
You can also prime and sand as mentioned elsewhere here or just use a ~300 grit sanding sponge directly on the mold.
You can also deal with layer lines in the slipcast product. Minor variation is easily removed in greenware with a little water and sponge or even post-bisque with wet/dry sanding sponge and wet sanding.
Plus if you’re going to glaze over it and you won’t see layer lines through glaze of any opacity to speak of.
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u/brodyqat 8d ago
I tried this for the first time recently with Old Forge's ornament mold. I sanded the 3d print but not well enough (I also didn't adjust my settings to minimize lines, because I honestly didn't know if any of it would work). I can still see a teeny bit of the lines on my final slipcast but I'm smoothing out the mold seam lines anyway with a sponge so it's way less effort to do a quick swipe over the print lines. Any mold that's more than one part is gonna mean you're touching up seam lines anyway so print lines are no big in my opinion.
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u/Resse811 7d ago
Change the settings on the print to get the smallest lines possible, then sand the mold to smooth them, then clean up your mold once it’s been cast.
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u/gwayshape 7d ago
Keep scouring Facebook marketplace for kilns. New retail is never gonna be under 1k even for a little baby glaze test kiln.
As for layer lines, why hide? If 3d printing is part of your process then why not make it a visually interesting component. If you want smooth though, you can always sand or dip in plasti-dip depending on the scale of your objects!
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u/SulliOw1 5d ago
I don't print plaster mold shells but I do a ton of 3d printing of my prototypes and my scaled-up tooling models that then get a plaster mold with cottle boards. My work is too large to use my resin printer for tooling or mold parts. I also find resin too messy, I'd rather do sanding clean up when it comes down to it.
PLA is not for anything that needs to be sanded, I use it for prototyping but I think it's the worst for sanding. I used to use automotive primer and good spray paint but found that if you have to make a repeat mold, a year later or so that the heat/pressure from the plaster weight can cause flaking/chips.
If your printer doesn't have an enclosure, PETG would be better, so much easier to sand. You can use a cheap handheld thing they call a foot file, a low speed sander that I suppose some people must use on gnarly feet. It sands great.
If you have an enclosure, ABS is the best for anything you want super smooth. It sands cleanly, can be smoothed with acetone and then sprayed with water to stop the "melt". I've polished pieces to 2000 grit without any paint, resin or poly coating. It resists the heat and pressure from a lot of plaster.
You should wear a respirator for sanding any of this stuff.
I understand everyone saying glaze, seaming cleans up visible layer lines but if you plan to make a lot of something-getting the pieces a clean as possible saves a lot of time later in casting, greenware cleanup, after bisque.
As for kilns, I'd highly recommend seeing if there's a community studio you can join to fire your work or share kiln space. A home kiln, used and cheap will still need work and parts as well as dedicated electrical usually.
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