You can use softened paste to:
  • Stick parts together - especially if both of them are dry.
    • Edible glue won't stick surfaces that are dry. At least one surface needs to be still soft/wet.
  • Fill gaps  (f.ex. between cake tiers) and holes (f.ex. after removing a bubble with a pin).

TYPES OF SOFTENED PASTE

To stick parts together use either:
  • flower paste (gum paste) + edible glue
  • a mix of flower paste (gum paste) and sugar paste (fondant) + edible glue 
To fill gaps or holes on the cake use:
  • sugarpaste (fondant) + water

HOW TO MAKE SOFTENED PASTE
  • For sticking:
    • Keep on adding glue gradually to the paste and mix until you get a tacky consistency.
    • You can use a mini palette knife to combine the glue with the paste.
    • Avoid making the mixture too wet - otherwise it will take long to dry and it might dissolve the parts that you want to stick together.
  • For filling gaps/holes:
    • Keep on adding water gradually to the paste and mix until you get a toothpaste consistency.
    • Avoid making the mixture too runny - otherwise it might dissolve the sugarpaste (fondant).
    • It will be easier to make it in a small bowl. You can use the round back of a spoon to get rid of the bubbles (press towards the sides of the bowl).

HOW TO APPLY SOFTENED PASTE
  • If you are sticking parts together:
    • Use the softened paste right away - it dries out quickly.
    • Apply a small amount (just enough to stick the parts together). If you apply too much it might ooze out and the parts might slide around instead of stick. 
    • For more precise application use a pin tool or the fine end of a dresden tool. For larger surfaces use a mini palette knife or a kitchen knife.
    • Use a soft, damp brush to remove excess softened paste or to smooth the surface if there's need.
  • If you are filling gaps/holes:
    • Put the softened paste in a piping bag. Close it and cut off the tip (adjust the size of the hole to the size of the gap/holes).
    • Apply the softened paste into the gaps/holes. Use a soft, damp brush to level/smooth the surface.
    • If you need to put the piping bag away for some time, put it in an airtight container or a bag.