Is there a difference in the two? I am making the #'s 4 & 0 for a fortieth b-day cake. Is is better to use gumpaste or fondant? Also, how would you stick the #'s on the cake so the are upright instead of lying flat on the cake. Can you attach them to candy sticks or skewers? Thickness? 1/4" to thick or should I try 1/8 "??
theres definately a big difference! although gumpaste is edible, it sets so hard (like rock solid) that eating thicker bits is a challenge. gumpaste will roll much thinner, and as it sets harder is really good for flowers and modelling. you wouldnt cover a cake with it.
fondant you would use to cover a cake, and is easier to eat. it will eventually dry out, but it takes a while.
so for your numbers, i would use gumpaste, or a 50/50 mix of fondant and gumpaste (which still dries harder and faster than fondant, but having fondant in the mix gives you more time to work with it). fondant on its own would work, but you would have to give it longer to dry.
to support it theres a few options. you can either make the shape, and stick things to the back with chocolate or royal icing - lollipop sticks, cocktail sticks, skewer, spaghetti, floral wire. you can also stick a copy of the number on the back so no one sees the support. or, you can push support inside, like floral wire.
how thick you roll it is really up to you id say.
im doing a number 13, will be using gumpaste, or a mix, with cocktail sticks on the back, rolled very thin.
Blend an equal amount of fondant and gumpaste together. This is often called "50/50." Color it. Roll it out out to between 1/8" and 1/4" thick (I usually do it 3/8" thick). Cut out your numbers. Allow to dry for a day. Turn them over. Allow to dry for another day. Melt white Wilton Candy melts in a piping bag. Place lollypop sticks or (what I use) bamboo skewers on back of numbers and glue with white Candy Melts. Allow to harden. Stick in cake. Take picture. Deliver.