ok im so excited!! been getting bulges on basically every cake but am always able to hide them with spots, etc but have been really worried about upcoming wedding cakes which are very plain and have no-where to hide. been reading all the topics about this and have been experimenting and this is what has worked for me:

Use thick buttercream for filling and dont use too much runny filling i.e. jam or lemon curd, etc - use a thinned down bc for crumb coat so as not to tear cake

then - this is what i know has been most important - after filling the cake press down all over the top firmly, its something so simple but when you think about it it actually makes so much sense as it gets any air out and also allows the filling to bulge out as it would after the weight of the fondant which you can then remove.

This has worked for me on all five cakes this week - not one bulge, i really cant believe i never thought of doing this, all that trapped air has been what has caused all my bulging so thanks to all you clever Cc'ers who shared your knowledge!!

You know what else works great...a dam. I pipe a dam around the edges of the cake and then add my filling, then press down, it works.

I agree, I always always use a thick dam around my fillings, even if its only buttercream. I also only put a crumbcoat under my fondant but I make sure the sides are level. I then let it settle for several hours.

Thanks for the great info Cathy! Will follow what you did!

Chippi

Definitly try it!! the dam would definilty be important if you were using really soft fillings like fruit, etc but i only every use chocolate bc or vanila bc with a skim of jam or lemon curd so i dont have an issue with fillings leaking badly - with me if was definitly air trapped betwwen the bc and the cake at least im not quite as nervous for the wedding cake now, i just kept thinking how close it was getting and i still hadnt solved this problem, i was picturing this cream 3 tier cake with 3 big bulgy lines round it and the bride in tears, etc - lol