Hello.

Before i say my problem i know that fondant decorations must be added at the last minute, but sometimes i cant do that. I must add them hours before.

Anyway, i make toppers and decorations and let them dry then add to cupcakes and close the box, not in the fridge.

After a while they are sticky and soft :(

Is gum paste better than fondant?and what is the best frosting in these circumstances? Buttercream, ganache... ? and if i use crusting buttercream will it be better? Since it will dry on the surface and not ruin fondant toppers?

Im sorry for the long post. But im very frustrated with this issue and thanks for any help :)

What sort of box are you putting them in? How far in advance are you making the toppers?

I put them in a regular carton cake box or sometimes wrapped in cellophane.

Sometimes i add them 6 hours before delivery

Gumpaste is better for decorations that people won't try to eat. Fondant and gumpaste don't like moisture, so icings will soften them, humidity in the air will, too. If I'm unable to place them last minute, I explain to my customers and they place them themselves. I have started to add melted chocolate to the bottom of my decos so there is a barrier between the icing and fondant. 

I like the idea of chocolate as a base. How many hours does it hold its shape if i used chocolate?

Make sure that whatever you are putting them in is not air tight as this will soften them.

Make the decorations a few days in advance so they have plenty of time to dry, this will give you more time before they soften.

A crusting buttercream may be a good option for you as the moisture from the icing is locked in. What do you currently use?

i think adding a drying strengthening agent to fondant is an option for you -- like corn starch or tylose powder

best to you

I've never timed it, so I'm not sure how long they can go before going soft, sorry! 

Ok, i made a batch of crusting buttercream. I think it may solved the issue 

But it was crusting alot. I used:

450 g powdered sugar

3 tbs cornstartch

200 g butter

Splash of vanilla

2tsp milk

I added cornstarch inspired by this recipe:http://www.wilton.com/high-humidity-icing/WLRECIP-123.html

But i was surprised that as soon as i stoped mixing it. The buttercream that was on the beaters was already crusting

And when i piped on the cupcakes after a while it was cracking. Is that from cornstartch? Should i reduce it next time?

Note:i like using all butter buttercream. No crisco or shortening.