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Egg Crate Module Construction

Egg Crate Module Construction

Here is an alternate module construction design from Bruce Smith of Auburn, AL
with comments by Bob Schrempp.

Bruce's concept is to build an light weight egg crate (honey comb) module. Bruce is replacing the standard 3/4" plywood sides with 3/8" plywood with some ribs for strength. He is adding a piece of 1/8" luan (door skin) to the bottom to create an enclosed box for strength. His design allows for a piece of 2" foam on the top.

I started with my lumber mostly cut to size already. The 3/4" oak plywood ends were 23 2/8" (to compensate for a sheet of 3/8 ply at each end) and the rails were 3 3/4". I cut a stack of 1 x 1 glue blocks to 3 5/8" and 10".
I laid out lines on the sides to show where the ends overlapped, every 12" for the vertical small glue blocks and 1" beyond the 12" mark for the 10" glue block. I applied glue to the 5 small glue blocks and stuck them to the side, holding them with clamps. I flipped the side over and tacked them through the ply with 1" brads in my nail gun (eat your heart out Norm!). I then flipped it back over and added the long glue blocks. Because I only had 8 gripper clamps, I did this in 3 sections. Figure 1 shows one complete side, and the second side ready to have the second set of glue blocks nailed.

Egg-Module01.jpg (93372 bytes)
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Figure 1

I then glued and tacked the rails to the ends, making sure that the ends were square vertically (the "box" is VERY flexible right now, so done worry about that right now). See figure 2 and figure 3 for details. I should have quit here for the day and let the glue dry, but I was anxious to make more progress.

Notice in figure 2, the sides are shorter then the ends, this is to allow for the foam top that will be added later.

Egg-Module02.jpg (78113 bytes)
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Figure 2

Egg-Module03.jpg (81091 bytes)
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Figure 3

I laid out lines every 12" side to side, as well as a centerline. I then used a chalk line to mark 1" on either side of all of these lines and 1" in from the sides. I then marked a circular cut-out with a plant dish I had handy <G>. I cut the end ones out, cutting straight in from the end to create appropriate access for clamping modules together. The rest will be cut out once the module is completely assembled. See figure 4 for a photo of the box, upside down, with the bottom skin sitting on it.  I went ahead and glued and nailed the skin to the bottom, but ran into problems because the brads didn't have a lot of holding power and the glue wasn't dry, so some pieces didn't stay together. I have repaired all of the areas that pulled apart, but a little patience would have gone a long way.

Egg-Module04.jpg (98880 bytes)
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Figure 4

I also measured the top skin (which was cut at 6' originally) to fit between the ends, as well as another longitudinal stringer which will go down the center.

More soon

Bruce Smith
Auburn, AL

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Page Last Updated 04/27/2005