Three-piece vertically printed mold with natches

These 3D prints slide into slotted side rails for each pouring of plaster. Since the plaster releases easily it is possible to use these multiple times. This method is suitable for prototyping in larger quantities than prints that integrate rails. These are printed on edge so print times are drastically reduced and surface smoothness is much better. This version has a bottom piece eliminating the seam across the base. It also enables putting embossed logos on the base. The holes enable mounting flush embeds - making it possible to sand the mating surfaces flat before gluing in the natches. The three-piece mold produced is shown on the bottom.

Related Pictures

Slotted side rails enable better mold making

In 3D printing of PLA molds for slip casting (especially case molds from which working molds are directly made), warping of the print is a constant problem. During printing, corners can pull up and away from the print bed (often after hours of printing). This drawing shows how slotted side rails enable sliding the mold in (this is the base of a bottle shape). The slots hold it straight. These slots also prevent the plaster from migrating around the edge and getting underneath. And they lift the print off the table enough to permit clip inserts in the holes (they hold embeds for natches in place). Notice that I have made a 1.6mm slot for a 1.2 mm mold - this was needed because the slicer has to insert printed support in the slot, this creates imprecise geometry and issues with assembly. The extra allowance assures trouble-free use (you may find it necessary to adjust this a little.

Pouring the v4 plaster beer bottle mold

This project is a testament to my wife's patience with me using her kitchen as a mold making shop. Most of the tools I need are there. A nice stable table to run two 3D printers, lots of room and plugins, electrical appliances, utensils and supplies of every type, good lighting. And pleasant company!

I have already poured PMC-746 rubber into 3D printed block molds and have printed and put in place stabilizers to hold the rubber in place. Embeds are in place on both the bottle base and bottom mold (upper right). The flexibility of this rubber is amazing, it makes possible extraction of the plaster base, although with difficulty. It also preserves the embossed logo on the foot. This is version 4 (version 5 will have a shallow base piece and modified sliding natches).

The $5 garage sale mixer does not pull bubbles to the surface so I just pull them up by counter-stirring with a serving spoon. A common sense workflow (never pouring any down the sink, cleaning everything in a settling bucket) makes this no problem in the kitchen.

Slotted natches make this bottle mold possible

These enable pulling apart the top halves of our ceramic beer bottle molds while the leather hard bottle is still embedded into the base. Starting upper left and clock wise:
#1 The 3D design for making a rubber case mold.
#2 It has been 3D printed in three parts (which are then glued together).
#3 PMC-746 rubber was poured in and the 3D printed parts were peeled off.
#4 Natch parts have been 3D printed.
#5 The embeds have been rubber cemented onto the rubber mold (to hold them in place during casting).
#6 Plaster was poured in.
#7 The plaster working mold has been extracted from the rubber, the embeds firmly rooted in place.
#8 The slots have been epoxied in place (lined up and positioned accurately so the natches hit the end of the slots just as the halves contact).
Centre: The mold partly assembled.

Links

Glossary	Mold Natches
Projects	Beer Bottle Master Mold via 3D Printing A project that took several years of failures and blind allies and is finally coming together - so much simpler than expected!

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