Station 3: Foam pipe insulation marble roller coasters The kids really enjoyed this activity although only 2 children chose to begin at this station! But almost all of them joined it eventually and we had foam pipe insulation going everywhere! A few of the parents said they were going to grab some from the hardware store to make marble runs at home too. :) We used the 3 foot long size but I have seen it done with 6 foot as well (Cut the insulation in half to double your track). I spent about $40 on the insulation you see here (8 sets of these) and we will be able to reuse it again and again.