take the tube off, change the valve setup on top. make it a pressure chamber for clear casting resin. perfect for what i needed, one extra thing you would need to do is cut out a flat piece to the inside diameter for the bottom since it has a small dip. another thing you can do to make a perfect bottom is get the white resin that sets up fast, pour it in the bottom about 1 inch thick. let it set up and leave it there. if pot is level you will have the perfect bottom. it holds pressure with no drop off in a 24 hour period.