Step 1: Materials and Tools
A pen would be nice
...and that's pretty much it!
Optionally, you may want to have an existing brimmed hat that fits you to help size your tape hat correctly.
As for your work space you will need plenty of room with a clean, flat surface where you can stick some tape and pull it back up without ripping off part of your table or getting your tape covered in filth.
Step 2: First thing's first...
1. Begin by tearing off a piece of tape the approximate length or width of the sheet you want. This first strip will form its edge.
2. Fold this strip in half, lengthwise with the sticky side out to form a crease down its center. Unfold the strip and set it down, sticky side up.
3. Tear off a second strip approximately the same length as the first and place it sticky side down onto the first. Be sure to line up the edge of the second piece with the crease running down the first strip.
4. Now take the still exposed half of the first piece of tape and fold it in on itself, matching its edge with that of the strip facing down.
5. Flip the whole thing over (this is where that clean table comes in handy) and set down another strip of tape facing down. Match its edges so only the exposed sticky side is covered.
6. Repeat step five until you have made a sheet of your desired dimensions. When you have reached that point, fold in the remaining sticky area the way you did in step 4.
** To make sure the sheet ends up extra smooth, when holding the strip of tape you are about to add, bring your hands together a little so the middle of the strip dips in. When you lay the strip down, make sure the middle touches down first, then place down the sides separately from the center, pushing out air pockets as you lay it down from middle to edge. I recommend waiting until you have the hang of it before trying this technique.
Step 3: The Brim
I recommend using a gel pen for tracing. It marks on easily and wipes off with a damp towel.
Cut the outside edge of the brim but leave the inside. Instead, cut out about an inch or more inside your mark, maybe even keep the whole thing filled in. After that, cut lines radiating from the center out, stopping at the inside edge you traced. This will give you tabs to anchor the brim to the body of the hat. The more cuts you make, the smoother the curve of the inside of your hat.
Step 4: The Body
Start on the body by making a second sheet of tape, its length the approximate height you want your hat, and its width the circumference of your head, or the inside edge of your brim.
When you build this sheet, rather than folding the end in on itself (step 4) leave the sticky part the way it is. When you reach the desired length you can stick the two ends together for a seamless barrel. Instead of starting at one end of the sheet, make your starting piece the middle and add strips outward on both sides.
Decide which end of the barrel you want to be the top of your hat and shave off the uneven edges into a straight line. Lay the barrel flat and shave off the bottom into a smooth arc. Try not to leave points at the ends of the curve, make sure it's nice and rounded.
Step 5: It's all coming together...
Fold in all the little tabs in the brim and tape them to the inside of the body. If you've been ripping your tape this whole time, you may want to consider using scissors to cut the tape holding this part together. A frayed end can stick to hair or peel up over time with use; this is where you are sticking your head. You should now have something close to a hat. Try it on and make sure the shape and size are about the way you want it.
Step 6: Put a lid on it!
Take this piece and stuff it down the body of the hat until it is flat against the table inside the barrel. Be sure the edges are as flat as you can make them before taping all the tabs to the inside of the hat. When that is done, flip the hat over and make sure the top is flush with the edges around it.
You should now have a recognizable top hat.
Step 7: Finishing Touches
Wrap the ribbon around the base of your hat. You are adding it here to hide the seam between the brim and the body of the hat, so try and follow that shape as best you can. It might help to tape on small anchor points to force that curve. Loop the end of the ribbon in on itself to make a small bow and tape it into place.
Now to fix up the brim. Rip out a piece of tape about half the normal width of the tape, and long enough to travel around the outer edge of the brim. Fold it in half, lengthwise with the sticky side out to create a crease down its center.
Hang this tape around the outer edge of the brim, aligning it with the the strip's center crease. When you have it all laid out pinch down the tape onto the top and bottom sides of the brim. This will add some mass to the hat's edges, cover up any mistakes made cutting the brim and smooth out the curve of the brim.
Step 8: Time to show off!
The rigidity of the tape itself should be enough to hold its shape, but if you're worried make sure to keep your hat out of the heat or direct sunlight, as it may weaken it, causing it to fall apart on you.