Bold Projects → Mosaic Projects → Mosaic Sundial

Similar Projects: Mosaic Sculpture, Mosaic Solar Lights

This was an ambitious and somewhat multi-faceted project. We decided to make a mosaic sundial for Tom’s mother for Christmas, and because a sundial by itself apparently wasn’t interesting enough, we wanted to incorporate solar lights so it would be pretty both day and night. The idea was to use small solar panels as some of the tiles in the mosaic and imbed the battery packs and lights inside the sundial, programming them to turn on in the evening.

I don’t go into detail on mosaic technique in this post – if you need more information on that, please see our Mosaic Sculpture post.

What we used:

• Round wooden base
• Styrofoam wreath and styrofoam discs
• Glass tiles, embellishments, and 6″x6″ stained glass squares
• 3″ x 1″ solar panels (qty 5)
• Wires, batteries, lights
• Hot glue gun
• Thinset mortar
• Waterproofing Glue
• Grout
• Numbers and Gnomon (for the “clock” portion)

Step 0: Solar Panel and Sundial Research

Two pieces of the project needed pre-research to determine specifics of the materials we would need: the solar panels and the sundial specifics. We had to figure out how much power we could get from various-sized solar panels to determine how many panels we needed to power the lights. We also needed to figure out the placement and size/shape requirements for the wedge and numbers to create a functional sundial. Working sundials are specific to the geographical latitude in which they’re being used – the gnomon (the part that casts the shadow) must be specifically designed for that latitude, and the hour lines (and placement of the numbers along those lines) must be accurately located, both with respect to the gnomon and to each other. You also have to put the sundial in the correct orientation (facing true north) but that’s easy to adjust.

Step 1: Assemble Mosaic Base

We wanted a sort of “wheel” look with stained glass wedges between the spokes. I used a glass cutter to score the stained glass squares, breaking them into wedges (these wedges didn’t have to be precisely sized since they would be partly covered up by styrofoam.

The styrofoam wreath made the outer portion of the wheel, and we stacked two discs in the center (to get the appropriate height). We then inserted, wedged, jammed, glued – any way that worked – the stained glass wedge into the space between the outer and inner Styrofoam pieces. Once these were secure, we cut styrofoam spokes and placed them over the wedges at appropriate intervals, blocking any seams and gaps.

Inserting styrofoam wedges to create “spokes”:

Since the sundial was intended to be placed outside (obviously…I’m pretty sure sundials don’t work indoors, not to mention the futility of the solar panel efforts), we did an extra waterproofing step to seal the seams between the stained glass wedges and the styrofoam edges:

We then coated the entire base with thinset mortar so we could begin tiling. We did all of this without the wooden base attached because there was still quite a bit of wiring work to be done for the solar panels and batteries. We ended up adding in a post later on through the center of the piece, which we used to bolt the wooden base to the styrofoam construct.

Coating the base with thinset:

Step 2: Applying Tiles and Placing Solar Panels

Since the top surface was flat, I had the benefit of being able to plan my designs without actually adhering any of the tiles. This was critical since we needed to know ahead of time where the solar panels would be placed so we could drill holes for the wires which would run from the solar panels to the batteries.

Mosaic design in process – note the bolt for the wooden base through the center (and please don’t laugh at my festive socks…it was a Christmas present after all):

Once the solar panels were placed, I finished mapping out the rest of the design and then placed rough cut outs of the numbers to make sure there were appropriate flat spaces at the desired intervals (most importantly not interfering with the solar panels) to fit the size of numbers we were planning to use.

Final design:

Final design with test numbers:

Once all the plans were approved, I adhered the tiles using thinset and allowed the base to dry.

Step 3: Wiring the Lights, Attaching the Base, and Adding the Gnomon Attachment Features

Before I could apply all the tiles, we still needed to attach the wooden base, which meant we needed to complete any of the inaccessible parts of the wiring process to allow the solar panels to power the lights. We chose to imbed most of the wiring into channels cut on the underside of the base to allow them to be accessible in case repair were needed, and installed the batteries and circuits into a small box inserted into a cut-out in the base for a similar reason.

We also had to conference in Tom’s brother, Sean, to discuss the attachment of the gnomon. Sean was using his CNC mill to create the gnomon and numbers for the project, which would be attached at the end. And clearly we needed some way of attaching the gnomon. Sean decided we just needed to include two posts in the base to align the gnomon, so we added those to the “design” of the mosaic.

Step 4: Attaching the Tiles and Grouting

Once the mosaic design was finalized, the necessary internal wiring was completed, and the wooden base was attached, I adhered all the tiles (including the posts for the gnomon), and allowed the piece to dry for 24 hours. We then applied the grout, allowed it to dry somewhat, and cleaned off the excess.

The cleaning/polishing process was somewhat laborious because of the complexity of the design and inclusion of features like tiny pebbles (good thing I love my mother-in-law…she was worth it!).

Step 5: Complete the Wiring

Tom then finished wiring the batteries and building the circuits and a bunch of other junk I don’t really understand.

Step 6: Creating and Adding the Gnomon and Numbers

Somewhere in Florida, Sean was making the gnomon and numbers according to the dimensions we had provided. When we showed up just before Christmas (it was incidentally quite awkward to transport) with the nearly-finished base, all we had to do was drill mating holes in the gnomon to match with the posts we had included, then attach and glue the gnomon in place. We then re-measured the hour lines to accurately establish the appropriate locations of the numbers, and glued those in place.

Step 7: Charge the Solar Panels and Enjoy!

Once everything was done, all that was left was to place the sundial in the sun to allow the solar panels to charge and make sure it all worked before presenting the gift!

Bold Projects → Mosaic Projects → Mosaic Sundial