Mountain Buzz banner

How to build a barrel pump

48K views 45 replies 21 participants last post by  DriftaBit 
#1 ·
I saw a post a while back about making a barrel pump and I thought I'd show you how I make mine. I've made more than a few and it is much easier if you and some friends decide you want one because they are labor intensive but they are pretty simple to make. You need a drill press and an adjustable hole saw like you see in the first picture. I made a 6" pump this time, but a 4" is the same. It is helpful to make test cuts with the hole saw because they are hard to adjust. The plastic I like to use is 1/4" vinyl (vinyl may be measured in metric). I've also used HDPE but it is a bit soft.

First you need to adjust the cutter so that you cut 1 circle that fits snugly in the pipe, and then 1 circle that is about 1/16" or 3/32" looser. The snug circle will have 4 circles cut out of it. This holds the gasket as the pump is drawn up and allows air to go around the gasket. The loose circle holds the gasket as the pump goes down and seals against the plunger and the walls. You need some space so that the air can go around the disk on the up stroke. These are assembled with a 1/4" SS bolt with a nylock nut for a spacer between the 2 disks and are bolted to a 1 1/4" pvc schedule 40 end cap. It is helpful if you use a cap that is flat and not round. I get the flat ones at Sutherlands. (pictures 2 and 3)

The end caps are 6" DWV caps. The pipe I use is SDR 35 DWV. A hole is cut to accept a 1" slip x 3/4" threaded coupler in the side of the cap that forms the bottom. For the top the hole saw is adjusted again to create another vinyl disk that fits tightly inside the cap. Then the saw is adjusted again and a hole is made for a 1 1/4" pipe to slide through the center. I cut the cap and the vinyl at the same time to help keep the hole centered. 2 holes are cut in the side for a handle and to allow air to enter the pump. I use a forstner bit or a spade bit for these holes. (picture 4)

The hose is attached using the 1" slip x 3/4" threaded coupler which is pushed through the hole in the bottom cap (I make mine snug) and then I have cut in half a 1" slip coupler. This coupler conveniently also fits inside of my check valve which is a dishwasher drain valve. Try a couple of couplers or you may have to sand the outside of the coupler. (picture 5) A notch is then cut in the pipe so that it fits over the check valve/hose assembly. (picture 6)

To make the gaskets I made 2 identical disks out of vinyl with the hole saw that are a bit larger than the bore of the pipe. I use craft foam and use a 1/4" bolt to sandwich the foam between the disks. I spin this on a drill and use a razor blade to make a smooth cut. I then use 2 smaller disks and a 1/4" bolt and repeat to make the o-ring hollow. If you look close you can see the outline of the barrel. Pictures 7 and 8

I then test the pump and then glue everything together. Make a handle out of 1 1/4" schedule 40 pvc pipe but I use a 1 1/4" schedule 80 T for the handle. I use a 3/4" ID vinyl vacuum hose and a 3/4 threaded to 3/4" barbed 90 elbow

The last 2 pictures are probably bit but they show the gasket in place and they also show a finished 4" pump. I use an abs cap for the bottom because they are flat and all of the DWV caps that are 4" have been round. There is an adapter for the DWV pvc pipe to ABS. it is white and a little of it can be seen in the picture. There is special cement for ABS to PVC that I use but these don't hold much pressure.

Hope this helps.
 

Attachments

See less See more
10
#4 ·
a few more things

1. I said the "star" piece should be snug. It should not touch the sides but should be very close. It may even be ok if it is the same diameter as the top but I have not tried that.

2. Make sure the check valve is not seated too deep. The check valve needs to open all of the way, plus I think the membrane flexes. If the membrane hits the PVC it will stop air from leaving the pump. To check this dry assemble and push really hard. Back pressure from the hose also seems to affect it so put your hose on. You may not even need to gluethe check valve on depending on how tight it is.

3. To hold the top on the pump I just drill a hole in the cap the size of the SS pan head screw I am going to use.

4. Heat the hose to get it over the barbed fitting.

5. For a leafield I use a 1/2 inch PVC riser, cut the threads off and taper the end with sandpaper (you can turn it on a drill) until it fits tight into the valve or use the Military valve adapter from NRS and a piece of cPVC. Use a small screw to hold it in place. The 1/2 riser works the best for a leafield valve, but make sure you use the screw because they fit tight and come out in the valve.

6. I've use 1/4 foam, that is a bit much sometimes. 1/6" is too thin but you can use the adhesive foam and glue two of them together. 1/8" or 3/16" would be best but I can not find it locally.

7. I cut the handles to about 5 1/4" for a 6" pump before I glue them into the T fitting. I'd cut the PVC to 4 1/2" for a 4" pump Then round the edges to make them comfortable.

8. I also use a small aluminum rivet to hold the top two pieces together as seen in the picture.

9. I've made 3" pumps without a hose and the fitting in a domed cap for a dry box pump. The check valve is different on those though. let me know if you really want to do this one they are a bit tougher.

The hose is the most expensive part ~ $16. but overall cost is about $55-$60 for a 4" pump
 

Attachments

#8 ·
Quick question about your pump

Hey, I love this write up and am gathering the materials to make my first barrel pump. My only question is why the need for the inner vinyl disc on top? The one riveted to the underside of the cap? Is there a reason that the cap alone wouldn't be sufficient for the top? Thanks again for the awesome write up and photos!
 
#10 ·
Hey, I love this write up and am gathering the materials to make my first barrel pump. My only question is why the need for the inner vinyl disc on top? The one riveted to the underside of the cap? Is there a reason that the cap alone wouldn't be sufficient for the top? Thanks again for the awesome write up and photos!
It cushions the up stroke and keeps the cap from breaking.
 
This post has been deleted
#11 ·
Caverdan has it right. It adds an additional gliding surface to keep the plunger centered and it also provides additional support for the straps.

Best of luck. I'm interested to hear how hard these are for others to build. Remember the tolerances do not have to be too tight.
 
#13 ·
Love posts like this and registered just for this. I am considering building a couple of barrel pumps after seeing this post and seeing the price tags for 6" pumps. :) I have a few questions.

1) I am unclear on where the gasket (shown in pic 7 and 8" goes and what it does in the pump as whole.

2) What kind of dishwasher check valve you suggest for this. I see various designs out there and Im not sure which valve to obtain for this project.

3) Why rivet the top two pieces together and not just use pvc primer/glue? Simply to avoid buying the glue if you did not have some on hand or is there something Im not getting here?

4) The top cap remains unglued from the main body, correct? I do not see how that stainless pan screw holds it together under vigorous pumps and does not mutilate the discs on the up stroke. Could you expand on that a bit?
 
#14 ·
1. The pictures in 7 and 8 are the jigs I use to cut the gasket material. they are slightly larger than the bore diameter of the pump. I cut them with an adjustable hole saw and then sandwich a piece of foam between the two pieces (you need 2 large and 2 small plates) and use a razor blade to cut the foam.

2. I use the oatley air vent for my check valve
https://www.amazon.com/Oatey-39012-...qid=1489168781&sr=8-6&keywords=oatey+air+vent

3. I rivet the top pieces together to hold the handle/strap in place and the PVC and whatever you made your other parts out of (Vinyl/HDPE/UHMW/polypropylene) probably will not glue together.

4. The SS screw that holds the top on does not mutilate the top disk because there is space between the disk and the cap. The space is created by the end cap that makes up the plunger assembly. It is about 1 to 1 1/4 inches tall. This will hit the top of the cap before your screw hits the disk.

These pumps are easy to build, but they take a bit of work and time. There is a reason they charge $200 for a quality pump!
 
#15 ·
Thanks unlucky for the detailed instructions. Went together without hitch. I'm going to tweak the gasket a little and see what the pros and cons are as to thickness and diameter. I'll also play with how much to cut out on the lower gasket holder (spider thingy, for lack of a better term). I think I may have cut too much and don't get enough support out of it as I should. It works fine but bleeds of a little pressure.

Sent from my SM-G930V using Mountain Buzz mobile app
 

Attachments

#16 ·
Elkhaven - It's nice to hear someone has used the directions and successfully built one. Looks good! I have yet to run into someone on the river who has built one.

I noticed yours does not have a base. They are a beast to put on when it is all put together but it is possible.

I don't think the fit of the "spider" is not too important. A little loose seems to be ok. I think the gasket life may be better with a tighter fit though.

As far as gasket thickness goes if the fit of the plunger is good you can use 2mm foam and it offers very little resistance. If your space is a little looser you will need the 4mm foam. It has a touch more resistance especially at first but they do loosen up a touch with use. Regarding the diameter of the foam I don't think it matters to much as long as it's larger than the pipe. The foam squishes to fit. Diameter does not effect resistance as much as thickness does.

I have not worn a gasket out yet. I have seen some used commercially for 3-4 years and still no failures.
 
#17 ·
I love this kind of shit. I didn't even need one, but the project has been eating at me ever since I saw this thread...

What did you do for a base? I thought about bolting something on and sealing it with neoprene washers, but decided against it for this one. I have enough parts to make another, so I'll do something for that.

Sent from my SM-G930V using Mountain Buzz mobile app
 
#18 ·
If your pump bleeds a little air than your plunger disk has too much clearance. Step up to the 4mm craft foam. You only need about 1/16" clearance for the plunger.

Typically when people test a pump they plug the end of the hose and jump up and lean on the handle. This can momentarily generate 15+psi. If your plunger clearance is small it will hold this pressure even with 2 mm foam. If your pump bleeds a little bit of air you won't miss it too much at 2 psi.
 
#19 ·
I didn't realize I didn't post pictures of the base. I use the same material for the base. Choose your shape. Some are rectangular and some are round with a flattened side. Use the same hole saw to make the base. I use 2 stainless steel counter sunk 1/4-20 X 3/4" bolts with nylocks and fender washers on the inside. Just put a bit of silicone between the base and cap. I put a touch around the countersunk head too. There is not much pressure to leak out I just don't want water leaking in if I'm standing in the water pumping.
 
#22 ·
That's right markhusbands. When the plunger is pushed down the gasket seats and seals the chamber. When the plunger lifts up the gasket no longer seals with the top of the plunger and it is lifted up by the spider or star. Air then enters the pump by flowing around the small space between the plunger and the wall of the pump. When pushed down it re-seats against the plunger and wall and the process starts all over.

This is the same regardless of whether you use an o-ring or a foam gasket in a pump.

Foam makes a great gasket for a low pressure pump because it easily expands to fit the uneven sides of the pump and it has very little friction on the walls of the pump. O-rings need lube to overcome the friction on the side walls and need a very smooth wall to slide against.
 
#25 ·
I have never looked at an nrs pump or the check valve but a check valve stops a fluid from from flowing in one direction. Functionally there would be no difference. The check valve can be omitted if you are inflating a leafield or H-R valve. Only a military valve needs a check valve. You may also want a check valve for a pool toy or air mattress.
 
#27 ·
Quick Q... you mentioned a base on my earlier post, we're you refering to a foot hold or the outlet plumbing... I just noticed I posted the wrong pic. It does not show the outlet at the bottom. Do you build a "foot peg" or "hold" like Carlson or just wedge the pump between your feet?

Sent from my SM-G930V using Mountain Buzz mobile app
 
#26 ·
Great write up thanks unlucky! Where do you get the vinyl that you are using for the discs? Also, the four circles that get cut out to make the spider, do they have to be a certain size or do you just need to get the basic shape?

Thanks again!
 
#32 ·
2 Pumps done and working on a third.



Whoa signed back in and found an active thread where a dead one once was. Sorry for reviving a such old thread but this kind of thing gets me excited. I built two pumps already and am working on a third and to answer your question: For the vinyl discs, I bought sturdy cutting boards at Big Lots and they;ve been great. Make sure you get something tough and inflexible (The dollar store ones wont hold up.) If you have plastics warehouse or fabrication nearby you could consider those - my friend went to one and asked for sheet scraps and they gave him so many plastics that he could build a couple of dozen pumps.

Also some suggestions for you who read this thread: I used a 4-1/8" hole saw which works perfect for making the discs and I already had one for cutting out light holes in the ceilings. With those hole saw, I get the 1/16" clearance and a perfect circle and I can punch out discs in seconds. With those and a couple other right tools, it takes about 90 minutes working time to build a completed pump. (excluding dry times)

If I get my act together, I'll post some movies and pictures of my pumps (I modified the design slightly) tomorrow. I think some detailed pictures and a movie will clear up most of the questions I see here and help others skip the figuring-out phase that I had to go through myself on some parts and how everything works together.

My question out there to you guys, is there a way we can build a screw-in adaptor of sorts for the leafield valves? The 1/2" riser does work well enough but I would love to screw the hose in a half turn or something and just pump away.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top