Skip to main content

Building Custom Beeswax Molds with 3D Printed PETG and Silicone Resin

Through my beekeeping operation I accumulate dozens of spent frames from which I salvage beeswax.
Spent Frames

Until recently I created candles as a means of storage for refined wax, though it reached a point where candle creation exceeded consumption.

I decided to cast the refined wax into blocks for long term storage and began the process of creating molds. I pursued a number of concepts before settling on one which fit my needs; this post is will hopefully save others a fair amount of time as little information is available on the web for fabricating custom beeswax molds.

Guidelines for the project:
  • Use materials on-hand:
    • 3D Printed PLA or PETG
    • Silicone Resin
  • Must be capable of reliably imprinting fine detail; minor defects are acceptable so long as it fits within the definition of "rustic"
  • Technique must be adaptable across a range of sizes: 1/4 Lb to 5 Lbs
  • Preheating of molds prior to casting not required
  • Mold release agent (silicon spray) not required

PETG Mold

My first attempts were printed PETG molds. Easy to design though I could not consistently imprint fine detail - even with release agent applied liberally.
PETG Mold
Beeswax from PETG Mold

Two-Stage PETG Mold

The two-stage mold adds a second plate which imprints on top of the molten wax after pouring into the primary mold. My approach on the second plate was to incorporate lengthy extensions for the imprint detail - the plate face itself would not come in contact with the molten wax. This was a complete failure as the wax adhered while molten and slowly retracted from the extensions as it cooled, leaving a destroyed surface upon removal.

Silicone Mold

Most commercial beeswax molds featuring fine detail are made of silicone - no doubt this would be a viable approach. The process is a bit convoluted as it's designing a mold to create a mold:

1. Print PETG mold for silicone mold
1. Cast silicone in PETG mold
1. Cast wax in silicone mold

My first attempt was a partial success. The silicone material was more flexible than anticipated and thus did not provide enough base or sidewall support.

Silicone Mold

Iterating the design to address shortcomings is straight forward, though I had another concept which could provide more... flexibility.

PETG + Silicone Insert Mold

PETG functions well when molding shapes without detail at low cost and quick processing time. Silicone excels at detail with the downside of high material cost and various complications for larger volumes. The hybrid approach of a silicone insert coupled with various PETG molds provides the best of both worlds.

Design and printing of both PETG parts progressed without issue as did the casting of the silicone insert.


Integrated Mold

Beeswax casts well provided the mold is allowed to cool gradually; a slow peel from each of the four sides provides enough release to drop. Finished 1/4 Lb bars -
Casted Bars

Comments

Popular posts from this blog

GE Profile Microwave Oven - 3D Printed Turntable Wheel Repair

With the COVID-19 lockdowns in effect we're tapping our frozen reserves of past harvests and prepared foods more frequently. The microwave has certainly seen an uptick in meal prep. Unfortunately one of the turntable wheels on our GE Profile dislocated and became damaged beyond use which prevents rotation while cooking -  game over for achieving reasonable cooking performance. Lengthy shipping delays and complete shutdown of business is the norm at the moment so I decided to 3D print a replacement. With such a simplistic part, reverse engineering one of the working wheels took only a few minutes as did whipping up a model in SolidWorks. Print took ~15 minutes then snapped on and rotated like an OEM part. For those in a similar situation, I'm releasing the STL file for fabrication on your own 3D printer - hopefully there's someone out there who's life got a tad easier during these crazy times. https://github.com/TKBrown/GE-Profile-Turntable-Wheel

Rheem Pronto Tankless Water Heater Repair

Appliance failure #2! The culprit was our Rheem Tankless Water Heater and took a fair amount of spelunking through the web, service documents, and a good old fashioned teardown to resolve the issues - plural as there were actually two error codes generated. Error Code "76" The first error code indicated communication failure between the "Remote" (HMI device which attaches to the wall next to the water heater) and "PCB" (as there is only one printed circuit board in the unit, Rheem refers to it as "PCB"). Upon examination of the PCB, I noted a few of the capacitors had bulged. Typically one would desolder and replace with comparably rated parts, but with 1/2" of potting compound encasing the board, it would be quite the operation to selectively remove and re-pot. I came across a  random post on Amazon which mentioned resolving the issue by shorting the communication terminals with a capacitor - this implies that degradation of the capacitor(