A friend of mine asked me to make an electric guitar birthday cake for her daughter's 10th birthday. I found an image of a guitar on my computer and enlarged it to fit 2 A4 pages to use as a template.
I baked a chocolate cake in a roasting pan to get a large enough cake. Once the cake was cooled I placed the template pieces (base and arm were separate pieces) on the cake and cut around them to get the guitar shape. I placed the pieces together on a sheet of baking paper, joining them with a smudge of strawberry jam. To hold the pieces together and firm up the cake shape I made chocolate fondant and rolled it out large enough to cover the cake.
I spread a watered down strawberry jam mix over the entire cake and then covered it with and pressed down the chocolate fondant. I had enough cake pieces to make up the rectangle for the amplifier and joined and covered them with chocolate fondant too. I measured the depth of the cake along the frett board and rolled out some black fondant long enough to cut two strips about 4cm wide and about 30cm long. I attached that along the arm sides smoothing out the join near the neck.
I had mixed the purple colour a few days earlier and purchased some lilac glitter dust to enhance the colour. I used baking paper to trace lightly around the head of the guitar to get the right shape and cut that out of purple fondant making sure the edges sat nicely over the black fondant edge. I then mixed some black fondant with the chocolate fondant and came up with the colour for the frett board. I traced that out of baking paper and cut the fondant to the right shape and size.
Once I had done that I rolled out the purple and measured and cut the strips for the sides of the guitar and then tracing the outline on baking paper again I cut a template for the top of the guitar and made that from the purple fondant. The seam between the top and the sides just seem to make it more realistic. Next I made the white board using a baking paper template again and covered that with silver edible glitter. The fretts are white fondant and the cord to the amplifier is liquorish. The tuning keys are large silver cachous and I strung the guitar with pins and dental floss.
Everything else on the Rock Guitar Birthday Cake is modeled from fondant and either painted with silver glaze or dusted with glitter dust.