Rose-Pins for cake.

I have put this on here (not cookery) because I need a quick answer.   I have lost my pins, probably lent them out and never got them back.
I need them for tomorrow morning for my big cake.    Google suggests making my own.   I have three galvanised nails.   If I clean them well and then make the discs from cardboard, that'll be alright, will it ?     Mrs Bouquet

Well the cake is made now, and I didn't risk the nail as it is a competition.    It is just sitting now cooling.
Looks OK.  but the judges decision will determine the winner, and there are many people there who are better cooks than myself.    I haven't entered any of the flower/veg sections, as they all get so precious, I cannot be bothered, in the past when I have won classes, you can almost feel the knives in your back, and that is only the men  !!  The other class I have entered  is for a handmade Christmas decoration.   Last year I made a wreath, it is all felt, so that I going to be it.     Mrs Bouquet