When you're using vacuum power, moving water, or compressing air, chances are it's being
done with some type of a pump. We'll need one for future projects, so in this video
we're building a PVC hand pump, from scratch, that will do all three.
To start this project, you'll need these PVC parts from your local hardware store. The
1" pipe will become the plunger piston, and we can start working on that first. You can
see this 1" pipe is a very close fit when pushed inside the larger tube. There's just
a slight gap between the two, but in just a minute they'll be perfectly air tight. I
chose to use a few pieces of two by four to hold this piece in place over the blade of
a table saw. Let's measure out 2 marks from the end of the pipe, at 1", and another at
2". You can see here that I've adjusted the blade so that when it's cutting into the pipe,
it shouldn't cut any deeper than halfway through the plastic. At this point we can get the
blade spinning, and hold the pipe in place with one hand, while using the other hand
to carefully rotate the tubing. This should result in a little groove all the way around
the pipe.Now let's repeat that at the 2" mark as well, and now we should have 2 clean, and
uniform grooves like these. The grooves are cut so that we can seat 2 rubber o-rings in
place, and when they're fitted snug, they should be just slightly higher than the surface
of the tube. While we're here, let's seal this tube with a little PVC glue and a 1"
plug. Now the plug might be tight, so just give it a few taps with a rubber mallet to encourage
it all the way in. Now let's clean up the piston by wiping away the excess glue, and
use a bit of sand paper to smooth down the sides of the pipe. I'm using 220 grit sandpaper,
and you can see it cleans everything up nicely and gives the piston a smooth finish. Now
this piece of pipe only needs to be 26" long, so we can cut two 4-1/2" pieces from the top
to create some handles that we'll use later on. I painted all the fittings and adaptors
black, while the tubing got painted blue, except for the piston of course. Now let's
go ahead and cement it together. First we'll need to glue the coupling to the bottom reducer
bushing, then glue the bigger tube into that, making sure it pushes all the way to the bottom.
We can go ahead and cement the handle together, but don't attach it yet, just set it to the
side. We need to insert the piston first, so use plenty of lubricating jelly around
the o-rings and the pieces should connect together with just a push and a twist. Finally,
we can cement the cap on the top, and the hydraulic piston is complete. Now, if you're
wondering how the top cap was made, I just took a regular slip cap and drilled a hole
in the center with a 1-3/8" Forstner bit. The #320 O-Ring fit nicely inside that, and
I used a little more lubricating jelly around the ring
Now you can see the
piston sticks out just a couple of inches, and this is the place where we're gonna
attach our handle. When it's glued on tight, it should have just the smallest gap of clearance
when the piston bottoms out. Well now we have a piston. Let's turn it into a pump. To do
that, we'll be using two of these one-way check valves that were made in a previous
project. The threaded bushing at the bottom of the piston is designed to accept a 3/4"
nipple, and the threaded Tee fitting screws onto that. If you try this yourself, make
sure to use something like thread tape to ensure the connections end up water tight.
Our two check valves can connect in-line with the bottom of the Tee, and because they're
threaded, we'll have the convenient option of switching, or replacing them any time we
want. At this point, you should have a completely operational water pump, ready to test out.
It's very important that the valves point the right direction so that when the piston
is pulled up, water flows in, and when it's pushed down, it flows out the opposite
side. Alright, let's see what this thing can do. If we place something like a balloon over
the outflow valve and begin to pump, you can see the balloon blows up on every downward
stroke. If you try adding additional pipes to the valves, you'll be able to leverage
the pump with your feet. I tried putting balloons on each valve so you can see how every cycle
sucks air from the red balloon, and pumps it into the yellow. When all the air gets used
up, the balloon gets sucked inside. Now this opens up the option to using the system as
a vacuum pump, and we can get a rough idea on how strong it is by blocking the valves
from both directions. This time when the piston is pulled back, it creates a strong vacuum
in the chamber, which you can clearly see when we let go. For more variety, I tried
converting this into a vertical pump, and was able to pump 3 gallons of water in about
a minute. Each cycle seems to pump just a little over 2 cups of water, and I found that
by leveraging the pump with my feet, I could double the flow rate, and move over 5 gallons
a minute. Some additional features are that the handle can rotate a full 360º, and perhaps
my favorite is how easily it comes apart for servicing. If you need to get inside the pump,
just give the handle a sharp tug and the whole plunger comes right out. This gives you easy
access to clean it, or add more lubrication if you need it. Well now you know how to make
a simple PVC hand pump that can be used for compressing air, pumping water, or creating
a vacuum. If you liked this project, perhaps you'll like some of my others. Check them
out at www.thekingofrandom.com