What do you use for the joints on your foam costume

Greetings all,

I'm new to the rpf but not to costuming. I've been active on the lair with a predator 2 suit and a freddy build on some horror forums but the other night after watching avengers I had a dream I was Iron Man and woke up thinking well why not make it a reality lol.

Anyway I'm about to start a foam build and I had a question. What are you all using to attach pieces at the joints? ex. elbow, knee, etc. I'm trying to think of something that will pivot and not rip through the foam when under stress.

There a lot of amazing costumes on here and I thank you all for the ideas!