Introduction: Homemade Water / Air Hand Pump
This is my first Instructable so bare with me
I looked on here for a hand pump to make but unfortunately there didn’t seem to be an Instructable for it, but lots of people asking how to make one.
What I wanted to do was to build a pump for water to make my own version of a super soaker, but I didn’t want to spend lots of money buying non-return values and the like so I thought I would build it from junk I had hanging around. It works reasonably well, I think you might buy one that pumps better but this isn’t bad for made of junk, it does the job.
Heres a link to an animation of the working pump
Step 1: What You Need
Ok here’s the bits that you will need
a bike inner tube
Large PVC pipe (I used 35mm)
something to cap the Large PVC pipe with (I used 2 caps from some supplement bottles, whatever will fit that’s plastic, you could cut them out of a plastic sheet) and you will need to make 2 little caps for the valves so you will need some plastic there, maybe some plastic from thick bottle lids or make up tubs or something would be suitable.
Slightly smaller PVC pipe (I used 25mm)
5mm hose connectors
a piece of dowel (I used 16mm)
1 screw that will fit in the dowel without splitting it.
Vaseline (petroleum jelly) for lubricating the pump.
a drill with various drill bits
a utility knife
hot glue gun and many a few spare glue sticks
lets get making
Step 2: Pump Body/chamber
to make the pump chamber or body of the pump I cut 12 inches (1 ft) of 35mm PVC pipe
then I stuck a cap from a supplement bottle on the end, you could use anything you want to that would fit and be water proof I recommend something plastic maybe some 2mm plastic sheet cut to a circle the same outer diameter as the PVC pipe. This will be the out point of the pump where the water/air comes out. I put hot glue inside the cap then pushed the pipe on to it to hold it. Later on, just because I was paranoid I put hot glue round the outside to make sure it was water tight.
I then drilled a small hole thought the middle of the cap using an 8mm drill bit
Step 3: Starting the Non-return Values
The non-return values are simple; they are just the 25mm pipe and inner tube capped off.
Cut 2 pieces of 25mm pipe to 1.5 inches in length. You could get away with shorter but I didn’t want to. It may work out more efficient, try it out. run a utility knife through the inside of the pipe where you cut just to get rid of the swarf
next you need to cut out some tabs from the inner tube, these will form the flaps inside your non-return valves, cut a circle with a long tab on it (see the diagram), the circle should be slightly smaller than the internal diameter of your pipe but a lot larger than your hole in the pump chamber (mines 8mm)
align the part where the tab meets the circle with the inside edge of the 25mm pipe and hot glue it in place so the circle sticks out. The inner tube will curl slightly make sure the curl ends up facing out of the tube when the flap is folded back. NOTE: at this point I should have cut a slightly smaller thin ridged circle of plastic and stuck it to the inner tube so when folded back it was on the inside of the tube, but I didn’t do this I think it may be better if you did, but make sure it’s away from the tab connected to the pipe. Do that with both bits of pipe you cut off.
drill a hole in the side of the pump chamber (mine was 8mm) for the water inlet
now we are going to glue these to our pump chamber using hot glue
one valve, the inlet in the side of the pump chamber, should be glued to the chamber with the flap furthest away from the hole and the hole should be roughly center of the 25mm pipe. Make sure you glue on the outside so you don’t block the hole inside, make sure you glue all the way around so its water tight.
The other valve should be glued to the end of the pump chamber on the cap end so the hole (8mm) is in the center of the pipe, this should be done with the flap against the hole, so fold it back before you glue. Make sure you glue on the outside so you don’t block the hole inside, make sure you glue all the way around so its water tight. This will form the outlet for the water.
Step 4: Finishing the Non-return Valves and Fitting the Nozels
Now to finish off the non-return valves and fit our nozzles which will allow us to connect pipes, I used 5mm couplers so this will allow me to use a 5mm hose on this.
Ok so we need to cap off these vales so you need to cut out 2 circles the same diameter as the outside of the 25mm pipe.
I took a coupler and cut it in half to give me 2 nozzles, run a utility knife through the inside of the nozzle where you cut just to get rid of the swarf
now drill a hole through the middle slightly smaller than the outer diameter of the nozzles, again use the utility knife to cut way the swarf otherwise it will block water/air flow.
now hot glue the outside of one of these caps to the out let valve making sure you go round the edge to make sure its water tight.
Now do the same with the inlet valve making sure you push the flap inside before you glue.
Now you can place your nozzles over the hole in the caps and hot glue them in place making sure again they are water tight.
Step 5: Making the Plunger
Now we have our non-return valves fitted and out pump chamber made we need the plunger to pull and push the water.
cut out 2 circles from hard plastic slightly smaller than the internal diameter of the 35mm PVC pipe, only about 0.5 - 1 mm smaller no more. (I had to use 2mm ply as that’s all I had, I will replace this when I get some plastic.)
then cut a circle out of the inner tube about 1.5mm in diameter larger than the inside of the pipe.
Now stick one plastic disc to the middle of the inner tube, it’s important that this is dead center.
Then do the same on the other side with the other disc, making a sandwich with 2 plastic discs and 1 rubber disc.
Cut your dowel, measure and mark to the same length as the pump chamber, now put your hand around it after the mark and mark a bit above your own hand this will make it long enough for you to hold it when it’s fully down. Mine was 12 inches (the length of the chamber plus 5 inches for my grip, total of 17 inches long.
Drill a pilot hole though the middle of the sandwich and also in the center of the dowel
screw the screw through the sandwich and in to the dowel, make sure it’s tight but not warping or breaking the discs.
And that’s your plunger.
Step 6: Adding the Plunger and End Cap
ok now we have our plunger we need to fit it in the chamber
if we put the plunger in there right away it will jam, so you need to lubricate the chamber first, put a large amount of Petroleum Jelly inside the chamber, as this will end up pushed down the inside of the chamber coating the inside of it.
Also put some petroleum jelly around the shaft of the plunger, this only needs to be a thin layer
now push the sandwich end of the plunger in to the chamber with the petroleum jelly it should slide down nice and easy and tight fitting.
Now cut another cap the same size as the outer diameter of the PVC pipe jump chamber, then drill a hole very slightly larger than the diameter of the dowel, 16mm for the dowel so cut the hole about 16.5mm or 17mm if you’re feeling cheeky.
also drill some small holes around the main hole, this will allow air to come out of the chamber as you pull the pump to pull water in to the chamber.
Slide the disc over the dowel and hot glue it to the end of the chamber.
Once all the glue is set, it’s ready to use!!! You might find the first few pumps you end up with air but this is just the air from the valves which once expended will allow water to be pumped. If however you still find you’re just pumping air then you have a leak in one of the seals check them all and make sure they are water tight.
You don’t need the cap for the pump to work however it does stop the plunger coming out by accident, if you find it hard to pump with the cap on, try drilling larger air holes this might help. Make sure you cut the swarf away so the air flows nicely.
in hindsight I would make sure I make larger inlet and outlet holes and use larger hose and couplers to make the water flow easier as the pump is a little harder to use than I expected but the point is that it does work. The next one I make will be much easier to pump; I will put up a mark 2 version as soon as I have built it.
You could use it to pump water out of a pond in your garden to change the water, or bail out a boat with rain water in it. So many uses.