Wood – put small nails through plexiglass

This should be a good starter project, here are a few tips I've picked up over the years:

• Even pressure treated wood will deteriorate over time if it's exposed or in direct contact with the ground/moisture. Do what you can to protect it from the elements and get it raised off of the soil. Use a moisture barrier between wood and concrete.
• Take care to perfectly level the area you are locating this.
• Make sure your cuts are straight, preferably using a square to mark your lines.
• Measure twice, cut once.
• Look for the direction that the wood bows, mark the bowed up side on the wood, and layout all the wood with the bowed side up. You don't want the floor to be wavy or to have a dip in the center for water/dirt to collect.
• Assemble the sub-assembles first, driving your nails/screws from the side of the joists into the spacers.
• Make sure all connections stay perfectly vertical since they lose their strength when they start to tip over. You can use a clamp to get leverage and untwist a warped joist, but if the warp is too significant, I'd cut it into pieces for the short spacers.
• Pre-drill when you are within 2" of the end of a board and going in from the side (e.g. all of the sub-assembly nails/screws and the 4 corners). Other than that, you can avoid pre-drilling, but it may help you keep a straight line if this is your first build.
• Metal brackets to hang the joists will give you a stronger connection. They should include directions for the type of fasteners, which will likely be shorter but very thick nails.
• Nails will have more shear strength, but screws will be less likely to pull out. If you have a sub-floor going on top of this, securing everything together, then I'd go with nails. I'd be lying if I didn't say I'd put in at least a few deck screws in each corner.
• 3 1/2" is a good length for any nails/screws. That gets roughly half of the fastener in each piece of lumber. When in doubt, get a longer/thicker fastener.
• Any untreated nails or screws will react with the chemicals in pressure treated lumber and quickly corrode. Hot dipped galvanized nails or treated deck screws should be ok, but check the label on the box to be sure it will work with the chemicals in your lumber.
• For each joint, a 2x4 would take 2 nails, a 2x6 would take 3, etc. Stay about 1" away from the edge of the board and space the nails about 1 1/2" - 2" apart.

Here's a search result from ePlastics, a reliable plastics manufacturer (companies I have worked for have bought from them repeatedly).

Infrared transmitting (IRT) sheet was specifically formulated for projects requiring ultraviolet (UV) and visible light blockage while allowing infrared (IR) transmission starting about 750nm. The physical properties of this product are the same as standard extruded sheet and thus the same fabrication techniques apply. What makes this product special is its ability to transmit light in the IR region. We stock this in 0.060" and 0.118".

Note: All plexiglass sheet is infrared transmitting. This grade is opaque to visible light and allows infrared light through. Unlike glass, you can put all grades of plexiglass in front of DVR's, cable boxes, DVD players, etc. and your remote control, wireless router, etc. will still work. This particular acrylic material is black and only transmits infrared, which makes it ideal for hiding a CCD video camera.

While it's probably not safe to say that all acrylics transmit all frequencies of IR light, based on this I would say it's safe to say that most acrylics (and Plexiglas brand specifically) would allow transmission of remote control signals.

The particular result above is for a plastic that is opaque to visible light, but if you're looking for clear, you could probably call them and verify that the clear versions transmit IR light, even if you're not going to buy from them.