Basically I was getting really upset with the low quality wooden nest boxes they sell around here. I have to replace them every season and they are extremely difficult to clean and disinfect. I walked on a building site one day and got inspired to construct nest boxes out of the PVC plumbing fittings I saw lying around on the site.
Here's how it works:
1. For the body I use 4-1/4" PVC pipe, this is a bit narrower than the 5" wooden nest box but I compensate for this by increasing the hight/depht of the nest box.
2. I then cut the pipe in 6-1/2" pieces using an ordinary hacksaw. I used a smaller piece of PVC pipe which I cut open and marked a circle cut-line with a pencil.
3. At this point you decide if you want a half open nest box or a hole entry type box.
4. For the hole entry type box you glue a 4-1/4" female end cap to one side of the PVC pipe.
5. For the half open nest box you cut the one female end cap in half using a hack saw and glue that to the PVC pipe, the other half remains open. Like this:
The glued piece viewed from the top
6. After the glue has dried you can then start drilling the holes, I used a circular hole saw for the hole entry type box and a normal 3/8" drill for the perch
7. Most of the nest box comes apart for easy cleaning and to disinfect them
8. For my breeding cages I add a hook by drilling a small hole, the piece sticking out at the bottom of the hook I cut with pliers to prevent birds from injuring themselves when entering the nest
9. Here is an example of how I used the half open nest box in my breeding cage.
I hope this helps some of you out there, I'm really happy with the way the nest boxes work and they are really easy and cheap to make. Good luck
Minnesota is more "arctic" right now...sigh! 
