Heat Controller & Heating Pad for My Vacuum Ski Press

After setting up the vacuum table, my next step was adding controlled heat to cure epoxy more reliably. I planned and wired a simple PID-based heat controller to run a 2 kW, 120 VAC silicone heating pad — it’s designed to run on 120 VAC and lays right on top of the ski layup on top of the the vacuum table. To handle the current draw safely, I wired it with 10 ga wire, even though 12 ga would have been fine for the amps (~16–17 A max). Better safe than sorry!

In-progress – above is the schematic, which is wired in the same manner as most brewing setups. I was actually able to learn how to do this by watching a few youtube tutorials. It’s not as neat as I’d like – in hindsight, I would avoid putting any of the electronics on the removable face of the junction box so that the wires don’t have to be as long. A relay opens and closes the the 120 volt power source to the heat blanket and a transformer provides low voltage power to the PID controller that actuates the relay. The fan just moves some air through the enclosure to avoid anything getting hot, and the thermocouple is the input to the PID. The long wires turned into a bit of a rats nest.

I tested it out on a lamp – when the lamp turns on, it heats up the thermocouple, and when a set temperature is achieved the PID cuts power to the lamp, turning it off and it cools until the PID is triggered again. It works! Now I just need to run a circuit to the panel for it with a 20A breaker and should be good to go. More on that later.

I also started gluing edges onto the P-tex bases that I cut out. I used spring clamps to attach the edges tightly to the base and superglued the edges on every 5 tabs or so. I came up with a quick clamping jig to hold everything in place while attaching the edges:

Here’s the heat pad that I ordered. It will sit on top of the silicone sheet while the layup is under vacuum and cure the epoxy quickly. The aluminum sheet under the heating pad came in too – I will assemble the ski layup on that aluminum sheet and place that on the mold so it keeps the base smooth.