To wrap up, some Tips, Observations, and Lessons Learned.
1) Patience is a virtue.
This project took me a couple of months. Since I couldn't find any online info for the cold finger mod for my particular camera model, it was a learn-as-you-go process. This meant I spent a lot of time thinking, planning, and trying things. Since I often didn't know what parts I'd need for the next step, I couldn't order ahead so I also spent a lot of time on hold waiting for a trip to the store or for online orders to arrive. If you tackle this, hopefully this thread will help you move more quickly than I did. But this is still a job that requires a careful, thoughtful approach. Taking your time and working carefully and methodically will pay dividends.
2) Do it in the winter.
Since DSLR noise is worse in the warm summer months, it spurred me to tackle this sooner rather than later. But because it took a lot longer than expected, I lost a couple of months of good summer imaging nights. Plus, summer is a busy time and “life” kept competing with this job for available time. This would have been a much better winter project.
3) Have the right tools.
… or know someone who does. For the filter mod, Gary Honis' web site shows the tools needed for camera disassembly/assembly. Most of those tools, along with a smattering of normal hand tools, are needed for the cold finger mod as well. But in addition, some metal working tools/skill is required.
I purchased a Gyros rotary tool kit (cheaper version of Dremel) for $60 from Home Depot for this job and found it to be an absolute necessity. I got the kit that includes the flexible shaft, which made handling the tool in tight spaces easier. The abrasive cutoff wheel got the most use, but I also used some of the grinding wheels that came in the kit. I used a drill press for most of the drilling, but a portable electric drill should work fine. For the screw holes, you'll need a 4-40 tap and a countersink tool. For cutting the metal parts, I used a small table-top band saw. You can probably use a hack saw instead, but that would add a lot of time and effort. If you can get access to a band saw, it's a much better way to go. One more thing – a decent set of metal calipers like the digital calipers that Harbor Freight sells ($20). These make it easy to get precise measurements, and the pointed metal tips are very handy for scribing measurements on the metal parts at the right distance from the edge.
For the electrical work, you'll need the standard equipment such as a digital voltmeter, soldering iron, wire strippers, etc.
4) Take lots of photos!
Even if you have no intention of posting them online. This is a complicated job with lots of small steps. More than once I found myself referring to earlier photos of the camera to be sure I had things assembled correctly. I've noticed that photos have a much better memory than I do! Even if you never need them, digital photos are free. Take them as insurance.
5) Do tape screws to a piece of paper!
This is recommended on Gary Honis' site, but is so important that it bears repeating. For each removal step, tape the screws removed to a piece of paper and write down the step number. I found this made the reassembly MUCH easier, especially since it occurred a couple of months after the disassembly. Like the photos, that piece of paper had a much better memory than I did.
6) eBay is your friend
For some of the items you'll need, like the controller, project box, heat sink and TEC plate, even the copper and aluminum plates, you'll find a large variety and cheap prices from eBay stores. The downside is that some of these sources are direct ship from China so the arrival time can be a couple of weeks. Keep an eye on shipping costs although many sources ship surprisingly cheaply, or even offer free shipping.
7) Use aluminum as much as possible, copper only where needed.
Copper is a much better conductor of heat, but is also much heavier and more expensive than aluminum. Since the cold finger itself is thin, and the heat must be transferred along its length, copper is really the best choice to cool the sensor efficiently. But I used aluminum for the thicker base of the cooler assembly due to its lower weight and cost. And since heat is transferred through this part only across the shortest dimension (the thickness) it would not make much difference in efficiency to use copper. A copper heat sink would certainly do a better job of cooling the hot side, but there are a much wider variety of aluminum heat sinks readily available and inexpensive, and a coper heat sink would add a lot of weight.
That's it! I hope this was helpful to anyone else considering this mod. If you have any questions, I'll be happy to try and answer them.