Last week I posted about the DIY PID-Controlled Soldering Hotplate I designed and built to improve my surface mount soldering capabilities.
I mentioned one issue I was having with the hotplate on flickr. Specifically, the aluminum baseplate was getting too hot for comfort (literally) when I set the hotplate to solder reflow temperatures (180-220C) for more than a few minutes. At the time I thought it was due to radiant heat from the upper aluminum block transferring to the bottom plate. I later discovered that the ceramic spacers I used to hold up the hotplate were much more thermally conductive than I thought and the screws I used to attach the baseplate to the spacers were burning hot before the rest of the baseplate. It was conducted heat, not radiant, that was the primary cause of the problem!
McMaster-Carr to the rescue!
I was able to resolve the issue by reducing the diameter of the ceramic spacers from 1/2″ to 1/4″ and using all stainless hardware to attach the spacers. Now the baseplate stays relatively cool even with the hotplate at high temperatures for long periods of time.
Click on the pictures below or view the complete set on flickr.