I was wondering if it would be a good idea to use buttercream to make a tiara.
I found a tutorial, but the lady used fondant and a clay tool (which I don't have) So I was wondering
if I could use a buttercream instead.
Is your tiara going to be laying flat? Then I'd say yes you could pipe it. However, if you wanted it to stand and be more 3 dimensional then fondant and/or gumpaste would need to be used. You could try royal icing but it would be really fragile and I'd make more than one just in case.