Battery box part 2

Once the box laminates were all glued together, it was time to work out how to hang it off the bike, and paint it up. I'd already gone and bought some aluminium clamps from Pacific Customs, as I'd seen Jeff Wolf use them in his ebike build. Jeremy and I agreed that we'd be best to fashion a sheet metal plate to attach to the clamps, which we would in turn fix to the wooden battery box.

A clamp from Pacific Customs

The clamps were slightly too small for the seat tube, so Jeremy bore them out a little on the CNC router. 

The CNC router boring out the clamp

He then designed a mounting plate in Solidworks, and cut it out of stainless steel using the water jet cutter.

Cutting the mounting plate out of stainless steel

The finished mounting plate, screwed into the box

Matching holes were then cut into the flat face of the box. Jeremy did this with a more "manual" mill, using more traditional machine shop techniques. The box was then fitted with threaded inserts for the mounting plate and the lid.

Jeremy operating the mill

After the box was drilled it was time to get sanding and painting. My friend David Parker coached me through the whole thing. He recommended Auto Paint out in West Auckland. They hooked me up with everything: Sand paper, fillers, paint, and polish. They were extremely knowledgable, and happy to indulge all my novice questions about my odd-ball project. 

David helping me sand the box in his fancy workshop
The ply box was sanded, filled, sanded, filled, again and again. I used 3M Acryl-Green spot putty, and sanded as fine as ~200 grit. I started painting once I realised I couldn't work the box any smoother.

The sanded and filled box

I used car acrylic, which was colour matched by the guys at the paint shop. Four types of paint were used: Primer, base red, pearl red (which made it shiny and metallic), and a clear coat. It took me forever to get good even coverage. I also learnt that it's much easier to get consistent results inside in my garage than outside.

Grey primer on the box body

I kept on applying coats until I ran out of paint. The end result wasn't perfect, but good enough for the bike. 

Pearl coat on the lid

I started to get a sense that the project was coming together once the box was mounted on the bike. Note how well-matched the battery box's paint is to the rest of the bike. 

The bike with its new battery box


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