The acrylic case is the same dimension as the wooden case and it puts together in a similar way.
In this project we use Loctite Go2 Gel for the case and Elmer's Glue-All to attach the Merkblatt to the lid.
Before starting to glue the case, the Arduino must be given some standoffs first. The bottom of the Arduino is not flat. The pins for the USB and 9V Power connectors in the front are taller than the pins in the back.
In the wooden case, a folded post-it note is used as a shim, but this solution cannot be used here because the case is transparent.
The standoffs are created from the unused acrylic piece where the parts are cut from. Locate a thin piece separating the bottom lid sides and break it off. Break this part into small rectangles and sand them smooth. The exact dimensions of the standoff pieces are not critical because we will be using their thickness to raise the bottom of the arduino. They will be laying down on their 3mm side.
Once you have 4 standoffs, apply a little Go2 Gel to each one and glue them to the bottom of the Arduino. They will glue to the PCB. One will go to the left of the infinity arduino logo on the top left corner. Another will go to the left of the ROHS compliant statement. The next one will go on the top right corner above the USB connector. The last one will go on the bottom right corner, clear of the power connector.
Once this step is completed, the case can be assembled in a similar fashion to the wooden one, except that this glue does not require water. Use a little Go2 Gel in each pocket, if you use too much it will get squeezed out. Work clean. Try not to get glue or fingerprint on the sides. There is no way to hide mistakes here...
Once the case is glued, apply hair bands to keep it together. The curing period for this glue is 24 Hours. It does not melt the plastic, but it forms a strong bond. If any glue is squeezed out of the case, you can pry it off after it cures.
To glue the instructions to the lid, use the Elmer's Glue-All, print out an instruction sheet and cut it down to size. Apply glue to the back and place it in the lid in the desired position. The glue will show through the back, you can use the scrap piece of acrylic to practice your gluing technique. If a mistake is made, the instruction sheet and the glue can be removed by getting it wet and rubbing it off. It will remove clean and leave no trace.
This case is the right dimension to accept the Housework 1131 hinges, but I have not found a way to nail the hinges to the case yet.