12 inch PVC pipes are good.
I would invest in one of those vacuum sealer machine kits as well. But I would add maybe some small pieces of cardboard to the sharp edges, so it does not puncture the bag. I also add a couple of small silica gel packets as well for good measure. I have a bunch of race engine parts, this is something I do quite often. Now if could only find a vacuum sealer machine kit at Walmart to do my crankshafts.