Here's the hardware you will need:
1/4" wood board 16"x20" (Piano bottom)
1/4" or 1/2" wood board 17"x24" (Floor)
1/8" wood board 16"x16" (Piano Lid)
1/2" wood board 8"x4" (Piano Lid supports)
4 small hinges
1" wooden dowel or 3 wooden candlestick holders 6" high each (Piano Legs)
4 wooden candlestick holders 3 1/2" high each (Bench Legs)
Step 1: Build a cake board:
First: Print out a life size paper template of your piano. I got an image off the internet and printed it on 4 pages and taped them together. I used this for everything. This helps figure everything out and helps it all fit. Also, figure out the ratio of your cake to a real piano so you can use actual dimensions when possible. I wanted the front of my piano to be 16" across so I divided the actual piano size by 3.6. Now I know what to divide the height and bench by to make it look right. I drew a line across my template to show where I wanted the lid to be.
Cut these out using your saw and cover in contact paper. I really like using contact paper for my cake boards.
Next: Cut the 1/2" wood board into 3 sections. 6"x4" and 2 1"x4" sections. These will hold your piano lid.
I didn't take pictures of this, but if you are using a dowel, cut 3 sections 6" each, or find 6" wooden candlestick holders. I used a 7/8" dowel and I thought it looked too thin. You could go as wide as 1 1/2"
Go outside and paint all that black with a clear coat so the paint doesn't scuff off and all the frosting and powdered sugar will wipe off easier. Go ahead and give that a second coat the next day. You really want to be able to wipe frosting and powdered sugar off of the black.
Set those boards up, screw them all together to see what it looks like and if you need to make any adjustments.
Yes, I hadn't painted my piano legs at this point, but if I were to do it over again, I would paint them first, then assemble. Sometimes I get too eager to put stuff together.
Step 2: Decorations that can be made well in advance.
Oh yeah, cover your floor in marbled fondant ahead of time too.
Step 3: Bake your cake.
When you get to this point, chill your cake overnight. Cold cake is so much better to work with.
While the cake is hanging out in the fridge, make the bench. Screw the legs onto the 3"x6" board you cut from the scraps. Put 1/2" of cake on and dirty ice. Take a straw and poke holes where you want the button indents to go. Cover in fondant. trace lines in the shape of an X in the divots and add buttons.
Step 4: cover in fondant
Heads up, this cake takes a lot of fondant. I used 4 pounds of fondant and still had to roll it thinner than I would like.
Start in the front, cover the front in black fondant. Not the sides, just the front where the keys go wrapping it up around the top and into the inside.
I rolled out fondant for the "guts" and traced lines for the strings of the piano. Then I cut out the other parts, poked some holes, traced some lines and painted them gold with an airbrush. Then I put them on top of the cake. I should have put the sides on at this point, but the sides scared me, so I did something fun instead. I made the keys.
Quick, get that cake in the fridge so all that fondant can firm up. You don't want anything slipping of the sides or sagging. Ok, it will sag anyway, but after it chills for a while, straighten everything out and trim everything even along the top and bottom.
Cover the lid of the piano in fondant too. There is some cake rule about everything visible that is not a support is supposed to be edible, otherwise I guess you could just paint the lid black. I covered mine in fondant. That way it will also match the rest of the piano.
Step 5: Put on the top.
Oops, I forgot to paint my chopstick so I had to dig out all my paint again. Fortunately it is a really warm day and it only takes about 20 minutes for paint to completely dry.
Now, screw the piano to the floor, add the music holder, sheet music and bench and you're done. Piano cake in 5 easy steps (ok, only step 5 is easy)