My wife and her mother are working on a project to put 5 x 7 inch pictures in a wooden frame, and they thought it would be a nice touch to have a frame holder to display the picture on the tabletop. My thought, of course, was to 3D print one for each frame, perhaps in different colors.
When I asked my mother in law what colors she wanted, she asked, “Can we do it in clear?”
I’ve recently been learning about making molds and casts at the Phoenix office of Reynolds Advanced Materials, and so I decided to give clear frame holders a try. Here’s the concept drawing:
So I developed a basic plan, based on the following steps:
- Design and print a 3D frame holder, using FreeCAD for design, and Slic3r and Printerface for pushing the file down to my Lulzbot TAZ 4.
- After manually shaping the part a little, make a “negative” mold using any available mold material.
- Cast a plaster “positive” from the mold. Refine the plaster cast with some sanding as needed.
- Make a negative mold from the plaster cast, using some material suitable for multiple casts of the final item. (After all, I’m on the hook for four frame holders!)
- Cast into the fine-tuned mold, using epoxy resin, which comes out clear. Smoothness will depend on how smooth the plaster cast turns out. Some buffing will surely be required.
Step 1 – 3D Model
So the picture you see above – with the frame inside the holder – is a screenshot from within the FreeCAD design tool.
Essentially, there’s a thin (2mm) horizontal base on the back, to keep the holder and frame from tipping over backward. The side “grips” each have a slot to allow the frame plenty of room to be lowered into the holder without damage, but not so much slack that it will fall out of the back.
There were a few rough spots on the 3D print which needed some additional work. I used a little clay to shape some edges by hand, and a Dremel tool to smooth down some rough spots.
Once I had the 3D print prepped, I inserted the frame to ensure a good fit.
Step 2 – First Mold
With the 3D printed holder ready, I prepared Alga-Safe.
I’ll be adding more to this shortly… stay tuned!