I made my bator out of a clear plastic tote with the lids that fold together, dimmer switch, 200 watt bulb, and a computer fan connected to a battery backup power supply. I would not suggest making one out of a plastic tote hind sight being 20/20. Temperature fluctuates too much. Also the 200 watt bulb is overkill. We have been fighting the temp fluctuation since day 1. Matter of fact I came home from work one day and checked the bater and the temp was 120 deg. After freaking out my wife told me the temp was low so she turned it up but didn't realize how little you have to turn the dimmer switch to increse the temp. with a 200 watt bulb. Fortunately she turned it up less than an hour before I got home.
I just finished my second bator for the next batch of eggs since my wife probably cooked most of the eggs. This one is made out of a styrofoam cooler, two 20 watt lights that are made to go under cabinet (they are pretty small), and 5"x7" glass for a window from a picture frame and a computer fan. I am testing it now to see how it will work out.
By the way I just candled a couple of eggs and seen some movement in one of them.
Eric