Printara Mold Maker
Give Printara a master model as an STL and it designs a 3D printable mold around it, checks the pour for trapped air and hands you the print files.
Drag to move through the filmSwipe through the film
Free account. A mold built on your own computer is free; a build on our server shows its credits before it starts.
A real mold from a Printara Library: an adaptive shell with a fill port in its base, 5 printed parts, built on 20.9.2026. The film is rendered from its own print files; the front wedges are drawn see-through and the bolts and clips are not shown.
From a printed shell to a cast
01Master in the printed shellShellPlug in from below, 3 wedges closed
02Silicone pouredSilicone770 ml through the spout, then cured
03Master outOpenWedges off, master out through the foot
04Mold turned overTurnFill port on top, plug out
05Resin through the baseResin299 ml into the port under the sole
06Cast pulled outCast149.7 mm, its detail from the masterA real mold from a Printara Library: an adaptive shell with a fill port in its base, 5 printed parts, built on 20.9.2026. The film is rendered from its own print files; the front wedges are drawn see-through and the bolts and clips are not shown.
The film shows one real adaptive shell mold from start to finish. The fill-port plug screws into the base plate from below and the master stands on its seat; three printed wedges close round it. 770 ml of silicone goes in through the spout until it shows in the telltale riser, and cures. The wedges come off, the silicone jacket lifts off the plate and the master comes out through the foot. Jacket and wedges go back on, the whole mold is turned over and the plug unscrews from the fill port, now on top. 299 ml of polyurethane resin goes into the port under the model's sole; it fills head first and the air leaves through the same hole. After the cure the mold is turned back, opened, and the cast stands on the plate: 149.7 mm tall.
Eight mold types
Each type is a different way to reproduce a master. Mold Maker suggests one when you open a model; every type builds free on your own computer, and the price below is for a build on our server.
Free on your computer30 credits on our server
A printed jacket that follows the model at silicone thickness: a base plate and 2 to 4 wedges, one pour through the spout, and an optional fill port in the base.
Free on your computer20 credits on our server
One open-top cup for flat masters, with up to 36 cavities in one cup when you want several copies from one pour.
Free on your computer30 credits on our server
A printed parting bed, frame and sprue for two pours with release agent between them.
Free on your computer30 credits on our server
A rigid printed negative with no silicone, with 2 degrees of draft by default so the cast lets go.
Free on your computer20 credits on our server
A box or cylinder around the master: a base plate and two wall halves that key together, held by a rubber band in its own channel.
Free on your computer20 credits on our server
The open box poured as one silicone block, with molded guide grooves that show where to cut it open after the cure.
Free on your computer10 credits on our server
One printed tool you press into the material, as a shallow stamp of the design or at the model's full depth.
Free on your computer30 credits on our server
Vases, planters, cups and candle holders cast hollow: the silicone held in the printed shell forms the outside and a printed core forms the inside.
The diagrams show how each type works, not a particular build. The prices are what Mold Maker charges for a build on our server; a build on your own computer costs nothing.
How it works
Six steps from a master to a mold you can print, shown in the Mold Maker panels of the Printara Academy lesson.
Any STL works as the master: a model from your Library, one exported from Printara at the height you want to cast, or a file from anywhere. The lesson exports its bust as an STL at 150 mm.
Mold Maker suggests a type when the model loads: a flat master gets the Tray, anything else the Adaptive shell. You can choose any of the eight.
Silicone thickness, shell wall, wedges, how the shell closes, registration keys, vents and shrink compensation. Base fill port adds an opening in the base plate and a plug, to cast through the base or to slush cast.
On your computer
Free
The default whenever your browser can run the engine
On our server
from 10 credits
For a slow device or a model that may not fit in memory
Same engine, same print files
Mold Maker builds on your own computer whenever it can run the engine, and that build is free. For a slow device or a model that may not fit in memory, our server builds it for credits. Same engine both ways.
Make the master or the shell transparent, see where air could be trapped, move through the pour level by level and pull the parts apart before you print anything.
Print files (zip), the report, your master and the hardware to buy. Save to Library keeps the set; with a paid creator plan you can list it in the Molds category of the marketplace.
A build on our server shows its price on the Build button and starts only once you accept it. If it fails, the credits come back. After a paid server build, rebuilding the same STL file as the same mold type within 24 hours is free, up to 3 times. New accounts start with 0 credits.
Real example, made in Printara
The mold in the film, as its own report describes it. The master is an AI 3D model made in Printara from a picture made in the Printara Image tab; it was exported as an STL at 150 mm and built on our server in 55 seconds on 20.9.2026.
The fill port sits in the middle of the base plate, under the model's sole, and closes with a printed plug that screws in from underneath. That is why the resin goes in from the bottom: the mold is turned over, the cast fills head first and the air leaves through the same hole. The same port also takes a slush cast, one coat of 103.8 ml for a 2 mm wall rolled round and drained back out, but the report rates slush on this mold as marginal: 2.81 ml has no way back to the port.
The images are renders of the build's own print files, not photos of a printed mold or a cast.
Adaptive shell, fill port in the base
Output files and review
Every mold comes as one ZIP, with the steps to print, pour and cast it.
3 printed wedgesBase platePort plugSave to Library keeps every part file, the ZIP, the master and the settings. The set opens in a 3D viewer with a Separate slider that pulls the parts apart, and from My molds you can reopen it, sell it or make AI photos for a listing.
Save project writes a .printara-mold file with your model, settings and results, to open again later.
No 3MF and no slicer project: import the STLs into your slicer and use the print settings from the README. The silicone, the resin and the hardware are up to you.
Platinum silicone and resin-printed masters: the report reminds you that resin can inhibit platinum silicone. Follow the resin and silicone makers' cleaning, post-cure and compatibility instructions and test on a small sample first.
Who it is for
What a master and a printable mold are good for.
Copy your own sculpts, busts and minis: the adaptive shell or the one-piece cut mold takes undercuts, the fill port puts the resin in from the bottom, and the report tells you how much silicone and resin to mix.
A render of the mold on this page, pulled apart round its master.
Trays with up to 36 cavities, open boxes, and vessels with an inner core for planters, cups and candle holders cast hollow.
A press mold or stamp you print and press, as a shallow stamp of the design or at the model's full depth.
Rather have the mold made? The Printara Atelier in Prague makes silicone molds and casts in resin and plaster by hand.
Printara AtelierFor sellers
A saved mold set can be listed in the Molds category of the Printara marketplace with a paid creator plan, where buyers download the printable parts. Make sure the master is your own design before you sell it.
Make a printable mold shell for silicone casting Printara Academy, 5 min 5 s, with captions. Open the lesson page
Step by step
FAQ
A tool that designs the mold for you. You give Printara a master as an STL, and Mold Maker builds the parts you print around it: for an adaptive shell a base plate, 2 to 4 wedges and an optional fill-port plug, with a spout, vents and registration keys. The mold is computed by geometry from your master, not drawn by AI; the AI in Printara makes masters, for example a 3D model from a picture, and AI photos for a listing.
Building a mold on your own computer is free; a build on our server costs credits, from 10 per mold, and after a paid server build, rebuilding the same STL file as the same mold type within 24 hours is free, up to 3 times. Mold Maker is open to every signed-in Printara account, and the account is free.
10 credits for a press mold, 20 for a tray, an open box or a one-piece cut mold, and 30 for an adaptive shell, a two-part silicone box, a printed two-part mold or a vessel with an inner core. The Build button shows the price, and the build starts only once you accept it. If a build fails, the credits come back. New accounts start with 0 credits.
Mold Maker picks your computer whenever it can run the engine in your browser. It suggests our server only for a slow device (touch only, fewer than 4 processor cores or less than 4 GB of memory) or a model that may not fit in memory, and only if you have the credits. You can always choose. Both use the same engine: in Chrome and Edge the print files come out the same as a server build, in other browsers they can differ very slightly.
Figures and minis with undercuts: the adaptive shell or the one-piece cut mold. Flat pieces such as coins, tiles and soap: the tray. Clay, dough or leather: the press mold. Vases and candle holders cast hollow: the vessel with an inner core. Mold Maker suggests the tray for a flat master and the adaptive shell for anything else.
An adaptive shell can get a fill port in its base plate, closed by a printed plug that screws in from underneath. Once the silicone has cured you take the master out, close the mold again, turn it over and pour the resin into that port, under the model's sole: the cast fills head first and the air comes back out of the same hole. The same port works for slush casting.
For the adaptive shell, the open box, the cut mold, the tray, the two-part silicone box and the outside of the vessel with an inner core, yes: the printed parts hold and shape the silicone, and the silicone is the mold you cast in. The printed two-part mold and the press mold are used directly, without silicone.
A closed master goes in untouched: on this page all 1,918,134 triangles kept their coordinates. A master with holes in its surface is rebuilt on a fine grid so it can be molded, and the report says so; the advanced Simplify master and memory settings can also simplify it. master.stl in the download is always your original file, and your cast takes its detail from your printed master.
No. Mold Maker works from any STL master: your own sculpt, a scan or a model made in Printara. AI model creation is an optional earlier step, not a requirement or a guarantee that the master is suitable for molding.
On your own computer the limit is its memory, and Mold Maker warns you when a model may not fit. A build on our server takes an STL of up to 100 MB. A mold built on your computer can be saved to your Library up to 95 MB; a bigger result still downloads as files.
Not as printed. For chocolate or other food, cast a food-grade silicone mold with the printed parts and follow the silicone maker's instructions.
The air trap highlight and the pour preview help you spot problems before you print. For the mold on this page the report marks 0.99 ml of air that can sit under the master while the silicone goes in, and about 2.7 ml the resin can cut off behind lips when you pour from the bottom. They are a check, not a guarantee. Degassing, pour speed and vents still decide the result.
Yes. Printara does not claim ownership of what you upload (Terms 6.1); for models made with Printara's AI tools you keep ownership and give Printara a non-exclusive licence to display, reproduce, distribute and market them (Terms 5.2). With a paid creator plan you can list a mold set in the Molds category of the Printara marketplace, where buyers download the printable parts. You are responsible for making sure the master does not copy someone else's characters, trademarks or designs.
Open an STL, choose the mold type and build it free on your own computer. Print the parts, pour the silicone, cast.
Free account. A mold built on your own computer is free; a build on our server shows its credits before it starts.
Printara is an AI-powered creative manufacturing platform for creating 3D models, dioramas, laser-cut designs, molds and printable products.