Step 1: The Supplies
...yardsale, ikea, sears, walmart, homedepot, side of highway... etc
2. Next you need some plexiglass (acrylic glass/sheet)
...you can get this at homedepot or most hardware stores
3. Tape: Painters (Masking) and Athletic tape are what I used
...again homedepot...for the painters tape
...Athletic tape can be found in many places (for me I have it in every drawer) usually
Safeway, RiteAid, and Walgreens are good places to look.
4. Gluegun: any will do but get clear glue
5. Exacto Knife/Razer...homedepot
6. Dremel Rotary tool with cutting bit...The bit in the picture (below the tape) is good for metal, plastic, wood, and ceramics
7. Goggles for safety....the dremel will fling pieces of plastic everywhere
Step 2: Prep and Cutting
Put the plexiglass on top of the trunk. Align it so you can use as much of the factory edges as possible. This makes it easier so you only have to cut two sides. Put the Athletic Tape on the edges you will be cutting. It will act to protect the plexiglass from the dremel and give it a cleaner edge. Mark a line on the Athletic Tape where will be cutting. The athletic tape is semi transparent so you can draw your line easier. Don't try to use scotch tape because it will melt when you start cutting. Athletic Tape is like fabric and won't melt (or burn like the masking tape).
When you are ready to start cutting take the plexiglass off the trunk and put it on cardboard on top of a working surface (workbench...preferably wood) to begin cutting.
It is important to keep the dremel tool straight along your cutting line. The tool should be perpendicular to the cutting line and slightly above the cutting surface. Cut with a downward tapping motion. When you are through the 1/2-1inch section you're on the bit will punch into the cardboard and spin more freely. Move onto the next small section. The third picture is what happens when you don't use the tape. the fourth picture is a clean edge when using the tape. The last picture is a finished product look at one corner with the taped off good cut and the tapeless bad cut.
When you are cutting don't force it, use a small amount of force and just tap at the plexiglass. Set the dremel to about 3/4ths of max speed. Cut with a ratio of 1/2 second cutting and 1 seconds resting, this prevents the plexiglass from heating too much and melting, allowing a clean cut. You wont need to hold the plexiglass steady if your doing it right.
Step 3: Corners
I started by taping off the corners with Athletic Tape and marking the shape with a pen. The shape of mine as you can see is a "U" at a 45 degree angle into the plexiglass. I started by cutting each side of the U , stopping before it began to curve. I then Put the cutting bit at a harder angle (closer to 45 degrees ...the last picture is about 80 degrees) from the surface so I could take advantage of the roundness of the bit itself. I cut the curve in the U from both sides and just had the small straight pieces sticking out. There is probably a better way to cut a rounded edge (Exacto knife, etching bit, Heated bent wire...) but thats How I did it.
Step 4: Gluing It Down
...try to go back
...apply too much
...run out of glue
...stop halfway through a side
...leave the bottom protective plastic on
Plan how much glue it will take to do one whole side so you can have enough to make it the whole way without stopping to refill. If you have to refill have it ready to place in the gun when it starts getting low.
Apply slow constant pressure on the trigger and move at a slow constant pace along the edge. this prevents an uneven amount of glue. it doesn't look good when the glue is over the edge of the plexi.
If you try to go back you'll have strings and its hard to remelt the first layer of glue so it bonds with the new glue.
When I finished there were some spots where I needed to cut some excess away. The best method I found was to lay the razer blade on the plexiglass and tip it about .5 or 1/2 degrees off parallel and move it back and forth in a sawing motion. Trying not to scratch the trunk in the process. You can tape off the sides of the trunk with masking tape to prevent it from any excess glue and from getting scratched up.