: Hey Shawn
: So, yeah, I built the PVC pump. It didn't work right to start with because I
: used a bicycle inner tube for the inner tube bits. Then it didn't work
: right because my bottom disc wasn't sealing properly. Well... The second
: problem leads me to think that it might be easier or work better if the
: bottom disc was the diameter of the outside of the tube and just got glued
: on. Ok, ok, this removes some of the ability to field service the thing,
: but sheesh! How the heck do you make a disc the size of the ID of the
: pipe? Yeah - you wrote about maybe using a hole saw. But if I've gotta buy
: a hole saw, well, the whole venture is sure starting to get expensive!

: But, if you went to the trouble of getting a hole saw, you -could- make two
: discs the size of the ID and then sand just a wee bit off of one of them.
: You could then outfit both of them as described for the bottom one (inner
: tube to 1/8" less than the diameter, a bunch of holes) and maybe use
: the sanded one as the disc on the plunger... (Still a small problem of
: sealing...) If it worked right, it would probably be a bit less effort to
: use as well as being a little more effecient.

: (Not having asked ahead of time, I didn't put your link in the link box, but
: here it is for those who didn't already know it...
: http://www.geocities.com/shawnkayak/pvcpump/ )

: cheers!
: charles

: ps: OT: I've just tried brewing my first maple ale... I could give a
: preliminary report when I go to bottle later in the week, but it had a
: pretty high initial sg so it shouldn't really be ready for months and
: months to come...

Hi fellow gizmologists, Shawn and Charles,

I have made a few of these pumps, also with modifications. Starting with 2.5" pipe and using a coupling fitting on the bottom and a 90 degree elbow at the top. The 90 degree elbow will increase piston travel ie volume of the pump and have less resistance because the exit diameter is the same as the pump diameter. The tricky thing is locating and drilling the rod hole in the middle of the 90 degree bend. On the other end the coupling fitting holds the perforated disc with the flapper valve in place and can be notched or cut at an angle to accomodate the intake function.
Oh and one more thing, I tried different materials for the flapper and plunger valves and ended up using flat neoprene discs that I cut from an old dry bag. The flattness is critical to getting a good seal. I could get some photos in about a week if that would help. This is fun stuff, hope you are enjoying the process.

Reg