I am testing using royal icing to use as glue to stick large roses on the side of a cake. I have tested it by making it up and sticking it a large ball of icing to my kitchen wall about the same weight as the roses, it seems to be very strong but is very slowly slipping down, I am not sure if this is simply because its on tiles and wont do it when I stick it onto rolled icing? I have made it very thick, the consistency is so that I can pick a lump and gently roll it in my hand without it sticking my my fingers. Do I need to use anything underneath the royal icing on my cake as a primer to help it al stick or should it stick better to the cake than my wall? Any tips would be greatly received. :)

Start at the bottom and work your way up.

Let the ones at the bottom set a bit before you put the ones on above it and then they will support them.

Edited to say that that sounds VERY thick...  perhaps even too thick?  I've never made royal icing that thick, yet it's my strong glue of choice!

I've used royal icing to attach large anemone flowers made from petal paste to the sides of fondant-covered cakes and it works brilliantly.  At first I was worried that it wouldn't hold them but I've done this several times now and the flowers survived a bumpy (it's always a bumpy road when you're delivering a cake) 40 mile car trip.

I make the royal icing to the consistency of stiff peak.  Approximately 7-8 tablespoons of icing sugar to 1 medium egg white.  Then pipe a blob onto the base of the flower and place it in position.  Now you have to be patient and hold it there until it starts to take.  I slide it around a tiny bit to ensure a good fixing.  You might be there 2-4 mins for each flower if applying to a vertical surface.  Then let go and test if it stays put. 

It does slowly move to begin with but just keep an eye on it and keep moving it back and it will set eventually as if it's been spot welded in place!  It is a little time consuming but it's worth the wait.  Just make sure you supervise each flower for up to 10 mins after applying them.  I use a small paint brush to remove any excess icing visible under the flower. 

Good luck with it. 

Louise

Thanks for replies, I moved it onto a vertical wooden chopping board and it stuck very well with no slipping haha, so maybe tiles are to slippy haha. I am so excited to stick them on, I have made cream roses to add on to someone elses wedding cake, it already has loads of chocolate roses on there and she wants me to remove some and add cream ones to break it up. So hopefully the other chocolate ones will help support too, although I am worried about playing jigsaw puzzles with it, hope mine fit in the gaps :s x
 

These are my roses I have to stick on. Very pleased with them, not bad for second attempt at roses :)