sorry Rudy, I already have made these units, I get mine from a well drilling company, They drill house hold 6" wells and farm 12" wells. They have to cap the bottom piece of pipe, the pipe has small slices in it to allow water in bottom is capped to keep dirt out. It is a single cap, just like 6" pvc caps and is glues on. You can buy couplers and screw in caps. These are a more expensive. There should be a well drilling company close to you. I have a supply store 3 miles from here. If you wish I will get you some info. The concrete and thompson's might just work. but you'll need to cap the top.