In this instructable I'll be making a centrifugal water pump.
The materials I used to build it can vary in shape and size, but the idea remains the same.

The materials I used to make it are:

3v DC motor, this is from a VHS player.
Plastic canister (the motor must fit inside)
Impeller (made from a plastic wheel)
Epoxy or similar glue.
Screwable nozzles
Electrical wire.
0.5mm plastic sheet

The tools you'll need are:

A dremel, drill or any other tool capable of doing a hole in the plastic

Assuming you don't have any of the materials mentioned above, they shouldn't cost you more than $5.

Step 1: The Impeller

I started by making the impeller for the motor, I had to search in my huge "junk box" for something similar and I found some wheels that had the structure I was looking for inside of them.

I chose the big one and carefully with my dremel I removed all the excess of plastic (I wish I had a 3d printer, sigh...).

The hole its a bit big but I managed to fix it putting shrink tube on the shaft and then pressing the piece in.

Step 2: Fitting the Motor Into the Canister.

First we need to cover all the holes of the motor, we don't want the epoxy to get in an block it.

Once that's done, we weld the cables, a thick and round cable is recommended because that will make it easier to seal the power hole.

Step 3: Fitting the Motor Into the Canister

When the motor is sealed and a hole to pass the wires has been made, put a generous amount of epoxy at the bottom, and slide the cables through the hole and then the motor, you might want to add a spacer under it and at the sides to keep the motor centered.

Let it dry and apply more epoxy to the hole if necessary.

IMPORTANT: Some motors come with the shaft exposed through the other side, I had to cut a bit of it and put some tape to avoid the epoxy touching it, you can solve this problem using a washer as an spacer but it's a bit risky.

Step 4:

Next we keep adding epoxy, in my case my motor wasn't big enough to fit the hole perfectly so I put a generous amount of epoxy at the sides to keep it firmly in place.

Next comes the upper part, we cut a plastic washer of the right size to cover only the area around the shaft, this is made to make sure the epoxy is protected against chemicals and to add a more resistant surface.

Once the epoxy is dry I removed the mess I had caused with a sharp knife.

Step 5:

This is it, once the motor is tightly placed, make two holes for the in-out nozzles and screw them, I recommend making the holes slightly smaller and heating the nozzles a bit so they leave a threaded hole.

If you don't have too much experience you can try with an empty canister first and then add the motor just in case you make a bigger hole and you have to perform a dirty fix or lose it all.

This pump works quite nicely, it is able to send water about 50cm above itself.