Huge Repair Project

[SEAL]

Wait, there's supposed to be an O-ring there? Well, that explains that! But my brother (it's his gun) says he's content without the selector, because the stream is pretty much the same size as the 20X nozzle anyway.

Fishfan: I think the pressure chamber isn't as strong on the 2500 though, as evidenced by the range difference.

[marauder]

What kind of range are you getting? Mk2 should get 50. I havent range tested a 2500 without a selector.

[Fishfan]

I forgot to mention a slightly weaker PC. I can't be too sure, it might be a mk2 bladder from a 2000.

[SEAL]

It's definitely weaker. My brothers measured around 38-40 feet for it, and the nozzle is maybe a little smaller than the 2000s (and I heard that the 2000 can hit mid-50s if the nozzle is made a little smaller). Because of this, we found an O-ring, and stuck it where the old one was (though I have no idea what happened to it), and put the selector back on. It works, so now there's only one more gun that needs fixing (the 175). I'm going to go look for some parts for it later today.

[DX]

(and I heard that the 2000 can hit mid-50s if the nozzle is made a little smaller)

I have a theory that the 2000 has a double peaked range curve. Several models, especially from Buzz Bee, peak twice for currently unknown reasons. Toothpickmatt's 2250 integration achieved the greatest range at 10x. 20x was still 2000-class, but not as good as 10x. The same bladder obviously peaks again at around 28x with the stock 2000 nozzle. 10x and stock are the two places where people have observed a 2000 bladder clear 53ft. The actual first peak might be a bit higher than 10x, but no one I know of has experimented with drilling their 2500 nozzle plate.

[Fishfan]

Is the 2250 mod a CPS 2000 PC inside a CPS 2500?

[Neptune]

What did you cut it with? A saw? Just making sure.

[marauder]

I am skeptical of double range curves. It only makes sense if there are problems with lamination on some of the settings. See this mod http://www.dukesoakem.com/20xbetterthan20x.html

[SEAL]

What did you cut it with? A saw? Just making sure.

Not sure what you're referring to; the last thing I cut off was the 12K valve, which I used a hacksaw for.

Is the 2250 mod a CPS 2000 PC inside a CPS 2500?

Yeah, though you'd get the same effect by just sticking a 2500 nozzle onto a 2000, haha (though then it's obviously not stock).

I am skeptical of double range curves. It only makes sense if there are problems with lamination on some of the settings. See this mod http://www.dukesoakem.com/20xbetterthan20x.html

Hey, I wonder if that's what's screwing up my 2500's 20X stream. Maybe I should try that mod.

As for updates, I am going to work on the 175 replacement pump tomorrow. What I'm going to do is use a stick of CPVC (which happens to fit perfectly) with a piece of wood epoxied in one end (the epoxy will hopefully keep the wood from rotting). I'm going to put like 3 O-rings on it to get it to seal as well as possible, because I've heard a lot of stories about homemade pumps having weak seals.

[marauder]

Post pics of the process! Also, what is the size CPVC you're using?

[SEAL]

Sure thing. I'm using 1/2" CPVC. I believe it's the same size that Nerfers use to fire their homemade darts.

[SEAL]

Well I've been too busy to actually test the 175, but my brother (Firebird) did, and he said it didn't work very well. He said he had to pump it up a LOT before it actually did anything, and when he did, all he got was a weak spray. The funny thing is, he said it didn't leak at all. Any idea on what the problem could be? I don't have a whole lot of experience making pumps; this is the only one I ever made. I noticed the O-rings tended to slip out of their grooves a little (I added some electrical tape near one of them to stop this), but the pump fit so tightly in the shaft (*ahem*), I figured it wouldn't be an issue. Maybe I was wrong.

Picture:

[Fishfan]

Use grommets.

[Drenchenator]

If you are having trouble with the pump, I suggest this method that I used in Riptide.

In Riptide, I used two rubber grommets as a pump seal. They are basically thick rubber washers. To attach them, I just used a screw and a washer. I think it's much easier to make this kind of pump than pumps with O-rings, which usually require a lot of work to get right.

Lowes usually has a good selection of rubber grommets and washers in the hardware section. I wanted to use rubber washers at first, but Lowes didn't have them for 5/8 inch in diameter, so I used grommets instead. Either one works, though.

[marauder]

My one word of caution about the above method is that I've had several stock pumps, made in the above way, break off inside the pump duct. This happened on my first WWF Stone Cold, a 1000, and another gun. For this reason alone I prefer stock pumps with O rings over pumps with screwed in sections of rubber at the end. Fortunately with home made pumps you can greatly decrease the chance of this happening, you just have to use a much longer screw than the kind used in stock pumps. So, if you're going to do this method, don't use short screws.

[SEAL]

Meant to reply earlier. Thanks for the advice; however the wooden piece I glued into the end of the CPVC is only about half an inch long, so a long screw would go right through it. Is that an issue? Fortunately the pump shaft's ID is exactly 3/4", so finding a washer/grommet that fits perfectly will be easy, I just need to find time to do so. Right now I'm trying to repair my APH.

The thing that confuses me is that absolutely no water leaked out at all when my brother tested it (he said it just took forever to build up any pressure). Doesn't that mean the pump is working?

[Drenchenator]

If you're using a hollow tube, I'd avoid using the screw-on method, because there are several places where it could fail now. A solid rod works better because it can only fail at the screw, but a hollow tube could also fail at the glue joint.

If it's 3/4 inch in diameter, instead of CPVC you could use a 3/4 inch wooden dowel, which should avoid the previous problem entirely.

If no water leaks out, that means it is sealing and not leaking, so I guess that means it works.

[SEAL]

Well I don't want to use a wooden dowel for the pump because it'll rot after a while. I looked all over the place for a solid plastic dowel, but I couldn't find one.

Maybe I can bring it to the war for you to look at.

[HBWW]

My own experiences with wooden dowels have not worked out, period. I find that once soaked, they tend to drip and leak water. I would much recommend a plastic or aluminum/metal dowel instead. Rubber grommets should work; I've bought some myself but never actually used them. However, they seem like they'd be nicer than O-rings.

Using a screw or bolt to hold the seal has worked very well for me when building pumps. Unfortunately, the hollow dowel I used was too wide inside, so I had to rely on lots of epoxy to hold the screw in place. Perhaps there's a better solution elsewhere.

Drenchenator's pump posted above may work out a lot better than the wooden dowel pumps I've worked with because it relies on the screw and rubber grommet to seal, instead of on the wooden rod. I would still prefer plastic or metal, but those are more difficult to get the screw into.

I will end with this: Any pump that requires hand-work (i.e. making O-ring grooves by hand) or relies on epoxy to hold the O-rings (or hold spacers that hold O-rings) in place will probably not work. I've tried every combination of CPVC spacers and epoxy to hold on O-rings, and they just don't hold or they fail to seal if the groove holding the O-ring isn't absolutely perfect. Using a screw gives you a perfect place to hold the seal, and the pump I made using it has lasted a long time without failure. (Whereas pumps used to be the main failure component of my homemades, but not anymore.)

[Andrew]

I'd second a plastic or metal dowel over wood. I had a wooden one rot and snap on me while I was using it once. Plastic or aluminium would be good options as neither corrode. I couldn't find the right size or right type of plastic for a decent price, so had to use brass to replace the wooden one (aluminium would corrode the copper pump). I had to use a drill and bit as a homemade lathe to cut a groove for the o-ring. It works really nicely now, but was a pain to get right, and weighs a LOT.

NERFers have used washers to make homemade plunger heads for ages, and they work lovely.