[KyuuKetsuki]

I managed to get a prototype kind of working. Using the top portion of 2-liter soda bottles for the domes, and the sprinkler tube to suck the air out to control the pressure. Using electrical/duck tape to secure the tube and as cushioning around the bottom of the cut out portion (2 layers of tape, but is a bit thin and the edge still digs into the skin a bit). The issue I'm having right now is that is isn't fully airtight, where the tube and the top of the bottle is basically layers of tape, and the bottom isn't entirely airtight even when sucking. Would a couple extra layers of tape fix that? Any recommendations to make sure the top portion is airtight?

I'm not very handy, so sorry in advance if I'm missing something obvious.