Royal Frosting Layer-by-Layer

Here was our first attempt at printing with icing sugar. We followed the traditional recipe for royal frosting.

Here is our recipe for royal icing. Our modifications to this recipe for better printability are:

  1. use about one and three quarter cups of sugar instead of 2-3 cups

  2. add about half a tablespoon of some kind of fat (we’ve used lard, which prints well, but other possibilities include softened butter or coconut oil – neither of which we’ve tried)

Also, another important tip – freshly made icing prints the best. If you store it in the syringe for more than a few hours, it just doesn’t print well. And don’t store the syringes in the fridge, as the icing will then get too hard to print. Leftover icing should just be discarded (or eaten).

We use aluminum foil for the substrate. After printing, we put the substrate in the refrigerator for 24-48 hours. This will dry out the print and make it so it can be handled. The denser the print is, the longer it will take to dry out, optimized according to the size of the print.

This is a really cool use of the Discov3ry. I have a few questions in trying to do something similar myself. How did you adjust the settings in slic3r, to achieve a print where the subsequent layer of icing does not destroy the previous one? Was this achieved by using a different tip? I’m really interested in replicating this myself, but am in need of a few details. Thank you in advance for your help.

With our icing recipe and by optimizing the print speed, each new layer prints while the previous layer is still semi-soft. Ideally, you want to set the layer height so that you get the new material pushing in a little to the previous layer. This ensures good contact between layers.

Royal icing is a little different from store-bought icing. Royal icing is designed to harden into a more candy-like structure. This, combined with 3D printing, can allow for lots of interesting objects to be made that would be tedious otherwise. Our recipe modification retains the self-supporting nature of royal icing for printing multiple layers.

As for slic3r adjustments, you would set the layer heights for about 0.5 to 0.75 times the nozzle diameter. We usually used a nozzle no smaller than 0.84 mm. Make sure the flow rate is ideal enough to allow you to print at a speed of about 15-20 mm/s (a print speed much faster will give you whiplash effects in your print).

If you are just starting with this, try an easy, flat object first – something like a simple logo that goes up to maybe 10 layers thick. This will help you get a feel for this kind of printing before you try more complicated items.

Happy to help if you have more questions!