I was having an issue with uneven/uncontrolled cooling making larger prints split on my makerbot. So I made 4 little stands that hold a cardboard screen in place around the build platform. Works a treat.

Print out the stands. Find 3mm cardboard (the box that my makerbot came in worked fine for me) and cut it to size (74cm x 18cm was what I used) Fold the cardboard 25cm from each end and put the corner stands on. Put the end stands on, put it in your makerbot, around the build platform and print those big prints worry free!

I take it out for smaller prints and to clean the build platter.