subject: Filled Shells
tags: 3d-printing, water-putty
summary: I 3D-pront some hollow panels and then filled them with Durham's Rock-Hard Water Putty, as an experiment.
date: 2024-02-22

Filled Shells - 2024-02-22 - Entry 44 - TOGoS's Project Log

I needed a 4+1/2″×6″×1/4″ or so spacer in order to mount a 3D-prunt phone holder on a French cleat because the flathead bolts that I have are a little too long for the whole thing to work without a spacer (they would have poked out the back of the hanging French cleat and scraped the wall).

This seemed a good opportunity to try something I had wanted to try for a while: 3D-print a shell, then fill it with some kind of hardening goop.

The shell, in OpenSCAD

A good choice of goop would probably be epoxy or 2-part polyurethane resin. But I didn't feel like messing with those, so instead I used a mixture of sawdust and Durham's Rock-Hard Water Putty. And made three of them, while I was at it.

Filled shells with a coat of wood glue over the top

After the water putty cured, I sanded these down with a low grit sandpaper on an orbital sander so that the original PLA outline was visible, and chipped or drilled the water putty out of the holes.

Then I applied a coat of wood glue over the top, using my finger to spread it around, waited a few hours, sanded that, and applied another.

The next day I put them all in the oven at the lowest possible setting (170F) for an hour, mostly to speed up the curing of the glue.


For these quarter-inch panels, there was no practical reason to build them this way. Solid, or even infilled 3D-printed PLA would probably be just as strong, not to mention much less of a hassle.

These panels are, however, unique, and it was kind of fun to make them. And the phone holder works just fine.

Phone holder, holding a phone

OpenSCAD designs: