I've seen a few of his videos before. Seems to have some good ones.
Thanks for posting this one, as sometimes I need a low-pressure check valve, but just not wanting to shell out $30 or more for one after driving 50 miles to town! ...Now I just gotta get some different sized balls to keep on hand.
doesn't seem like materiel would go past the marble valve and get stuck.
a flapper valve would work better, could be made from some neoprene.
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you could make a weighted one with a nut & bolt/washer in the middle. look at a foot valve to see how it works.
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It'll work as long as there's back pressure. Same thing with the DIY model. Only thing with a flapper-type check valve is, if you install horizontally, the flapper needs to have its hinge up top. That way gravity helps close the flap so that back pressure can make the seal.