Here are some pictures of my newly constructed racks. I keep getting better with each design. If I was home more often I would have a lot more built. Each of these racks took about 8 hours each to build.
first is a 1 wide by 10 high 41 qt rack. This sucker is heavy. All the shelves are 3/4" laminated shelf board. The sides are MDF board. If you look closely to make the shelves wide enough for these tubs I had to add a 1X2 to the edges. Each shelf is heated with a 12" X 11" piece of flex watt. A power strip is on the right hand side that you can't see that each level gets plugged into only when in use or under test. The cord for the level that has the herpstat probe on it is a different color from the rest so you know that is the one that has to always be plugged in. The back is also a solid piece of MDF. All the regular wood was painted before assembly then touched up afterwords to make sure everything was sealed good.
Next we have a simpler rack that is designed to hold 18 15qt tubs. The shelves and sides are made of Laminated shelving board. The stops in the back had to be specially spaced to allow the lip to slide over them and actually stop on the side of the tub. This makes sure the whole top is covered and made the shelves just the right depth to work. Each level has a 4" strip of flex in a belly heat configuration. Each level has its own plug that goes to a power strip on the side that you can see in the above photo. The level with the t-stat probe is again done in a different color (White) to make sure this level stays plugged in all the time. The pegs are color coded pink for females and blue for males.
I like these designs and hope to keep them as our standard. The regulate temps very well and hold humidity well.