So today was a less that optimally productive day, but I did get some things done.
So, I was unable to locate any older power supplies hanging around my house. This is amazing considering all the computers I have made. I must have done some spring cleaning and forgotten about it, or they are buried in my mess. I suspect both.
Anyway, I asked my friend who is lending me a hand if he had any old power supplies he would be willing to sacrifice for a noble cause. He brings over a very
old power supply. Predates the 20/24 pin plug that all power supplies for the past 10 years have. If you have built a computer you will know what I am talking about. It is that monstrous rectangular plug with over 9000 wires that you plug right into an annoying part of the motherboard, usually where only infant fingers can reach. To use one of these power supplies it needs to think its plugged into a computer with the power switch on. All you need to do is short the green wire to any black (usually wire 13 to any black) and it will turn on and give you clean DC power at 12v and 5v, whatever flavor you like best.
This had none of that. It had the standard plugs you would see on any power supply, but then 4 wires that really were foreign to me. there was white, black, brown, blue. Well, after trying combinations of getting this thing to work, shorting out 120v ac and frying a power strip, I found out that a switch was made for this thing and was elsewhere. Awesome, would have saved me a good scare. I don't blame my friend. Not really...
On to the goodies:
I glued a piece of foam board to the plywood that will be the front of my cabinet with contact cement. The kind of stuff that holds formica veneers down. I have it clamped because the plywood was warped and I couldn't get perfect contact on all the edges.
After that had been clamped and the glue had dried, I put some silicone caulking around the edge of the foam so that there wouldn't be any sneaky air working its way behind there and getting into the low R value of thin plywood. You can see how I trimmed the edge of the foam here. I also sanded it down to make it slide in easily. This stuff smooths up like a dream when you sand it with 100 grit.
Then I moved on to working with the power supply WITH a switch attached to it. Below is a picture of the peltier sandwiched between its two heatsinks. I had to make some thermal grease as I only had a liquid metal type that I use on my computer that has gallium in it. Gallium makes aluminum rust so I couldn't use it here. I just used 600 mesh aluminum powder and a few drops of silicone oil to make a pretty close equivalent to what you would buy at the store. Worked really well in fact!
So now that I had everything working I needed to figure out some way to get the power to the peltier and two fans that would be moving air across the cold and hot heatsinks. I decided to use some old molex (not plugs, and solder the peltier and two fans to them to make things easy to use and modular. In the process of this I found out that the wires delivering power to the peltier are incredibly fragile and pop out easily.
That made me feel like this:
This happened not once, but three times because I am a glutton for punishment and clearly love to solder small contacts in tight quarters. Here I am soldering it up for the last time, do note the molex fitting in the back in case you were unfamiliar with that style of plug:
After that laugh and half I put some epoxy over the soldering points and along the edges where they meet the peltier.
I did the same with two fans. They are controlled via one molex fitting so they are both on or off at the same time:
Right now I only have an 80mm fan to put on the hot side. I will be moving up to a 200mm or greater fan once I get one, but for now it will be adequate.