I have to make a spong cake for 80 people, iknow its gott abe big, im thinking of just doing two cakes,  i am gonna put jam and cream in middle , then i thought i would buttercream it, now is this gonna be quite tricky? like the cake will just crumble apart, i am using bakel sponge mix..

thanks

I'm not an expert but I believe you should let the cake cool down completely before icing, and you would put the icing on it the same way you would on any other cake.

Yes you should definately let the cake cool completely, of you're worried about crumbs just freez it for a bit and then ice like normal!