Molding and Casting¶
This week I created a silicone mold from an FDM 3D print to make a fishing sinker out of concrete.
I also once again teamed up with Kerstin and Lars, the other students from HRW FabLab, to compare some of our first tests and gather the safety datasheets for our materials.
Design and Printing¶
To start off, a big thank you to my brother, who came up with the idea in the first place.
Not only is he really into fishing, but he also studies civil engineering and knows a thing or two about how to work with concrete.
After we discussed the idea, he quickly whipped up this technical drawing for me.
So I got to work in Autodesk Fusion, which I covered extensively in previous assignments such as the CAD week, 3D week and CNC week.
I followed my brother’s design pretty closely but thought it would be best to slightly undershoot the calculated volume, since I planned on using filler primer to get rid of the layer lines and other artifacts from the printing process.
I split the sinker in half and added back panels as well as indexing features to later be able to align the two halves of the mold.
I personally didn’t really like the shape all that much, so I created a second version with a slightly less boring shape.
Just as a sanity check I also subtracted my geometry from a solid block to simulate the molds.
With that done and looking good, I sent my positives off to printing.
You can find both of them in the Download section at the bottom of this page.
After about 2 hours I had my parts ready to go and began building some boxes out of carboard.
For now they are only held together by duct tape but I’ll seal all of the edges with hot glue once I finished postprocessing the printed parts to prevent the liquid silicone from leaking.
Speaking of post processing: I sprayed my prints with filler primer.
About 4 coats did the trick.
I then sanded them off.
Sealing off the boxes with hot glue was kind of a pain.