Why isn't my convex box working?

I got a plastic tub and put a cardboard lid on it, it's a little oversized but I taped it down with a lot of pressure so no air can escape I cut one hold in the middle, to light the candle through, I kept the cut out and covered it with foil so I could tape it on after I lit the candle and on either side of the input hole are two cylinders, one has a string attatched to it that's supposed to spin the foil spiral attatched to it. Both of the cylinders have foil over the top with small holes poked in them. I put the candle under the cylinder wihtout the string. What am I doing wrong? The spiral is supposed to start spinning after the candle burns up all the air and it's trying to suck air back in.