So many threads on bulging and I wondered if there is a way to test the density of icing that is needed to match the cakes density or weight so it hold together firmly under the pressure and doesn't squish out. Obviously stiff is good, but how stiff? How do you tell? Is there a scientific method to make sure you don't wind up with a blow out? With all the fabulous minds in here someone has to be able to spell it out in layman's terms.

I don't know Sad. Honestly, I never have bulging. I only dam when I have a curd filling, and then it's not anything more than my regular SMBC icing, which is not thick or strong at all. And I only recommend people wait for settling to occur because it's probably the right advice to give, even if I don't follow it. That didn't help at all, did it??

I am curious though why this plagues so many people. Is it not having cool cakes before they begin the filling/cooling process?? Using too much filling?

I also use SMBC as my filling and have had no problems wih bulging yet (touch wood). I fill my cakes and let them settle too.

On Sharon Zambitos Perfect Buttercream video she suggest adding more powdered sugar to your buttercream until it's stiff enough to actually for a ball with your hands. I've done this several times and have had great success with it.
Hope this helps.

I have a feeling that much of the bulging is caused by too much filling, not by an insufficient dam.

I use Imbc for my dam, and it works fine. I think if you are trying to bring your filling to the same height as your dam, (which seems like that could be 1/2 or so sometimes depending on the tip you are using), then it is going to squish out. I just use a 1/4 inch or less layer of filling and no problems.

I use the same icing, same density, that I ice with. Blunty, I just don't have time nor do I want to take the time to make up 2 or 3 different densities of icings when I'm doing a cake.

In my personal experience, I find that letting the crumb-coated cake sit overnight helps, and don't put the dam on the very edge of the cake. Give it room to "bulge" when you put the next layer on and while it settles. If you put the dam slightly inside the edge, then when it 'squishes', it pushes the dam to the edge of the cake .... not out and bulging OVER the edge of the cake.

I'm with debi, I just put the filling close to the edge then it has room to squish to the edge. Good luck