WBL with built-in pump - Advice wanted

[mr. dude]

Has anyone ever done it?
I don't really want to use a schrader valve, so I think I'll give it a built in, PR-type pump.
So my questions are:
What size pump should I use?
Is there a need for a pressure gauge?
How long should the pump be?


Note: Not to scale.
Yes, it's a doucheator with a pump. If I do end up building it, that'll be in a few months.

[cobralex297]

It definitely sounds like a notion that could eventually help to make a more efficient design. Of course, I'm sure it'll take effort to get the positioning of the pump right, so as to create an ergonomic and effective design.

[SSCBen]

It'd be easier to attach a bike pump to a WBL than to build one. It'd also be much cheaper given the price of check valves. I'd suggest duct taping a bike pump to an existing WBL to see how it works.

By the way, your design above needs a second check valve to work. You would get one pump in, but there's no wait for more air to get into the pump.

[mr. dude]

Thanks for the heads up about check valves! Does this fix it?:

I realize that it would be more expensive, but it's more practical than carrying a bike pump around wherever I go.
I want a bigger pump than 1/2", so that it doesn't take as long to pressurize (which is my main problem with the APH, mine takes 60-80 pumps to pressurize), if it doesn't affect performance like it does on soakers, so does it?

[HBWW]

I'm starting to favor over-under designs more. I, too, would suggest duct taping the pump on. Regardless of whether it's a foot pedal or hand pump, you'll have to re-postition while pumping for best speed, ease of use, and efficiency. That is, you can't be in a ready-to-fire position while pumping (like you can w/ soakers), but the fact that the bike pump is attached alone should make things much easier. On a side note, you may not need such a big PC.

If you're still going for a soaker-style pump, good luck getting that darn thing to seal... Well, even if it does seal, it'll probably be very stiff.



Edited By C-A_99 on 1199675029

[SSCBen]

Thanks for the heads up about check valves! Does this fix it?:

Yes, that's what you should do.

I realize that it would be more expensive, but it's more practical than carrying a bike pump around wherever I go.

I said you should duct tape the pump on the WBL in the same fashion you would attach this new pump. It would operate the same or better, at less cost.

I want a bigger pump than 1/2", so that it doesn't take as long to pressurize (which is my main problem with the APH, mine takes 60-80 pumps to pressurize), if it doesn't affect performance like it does on soakers, so does it?

The obvious advantage to wider pumps is that they'll pump more. But, wider pumps will be harder to move. Pressure over an area equals a force. Therefore, the wider pumps will require more force to get the same pressure as smaller pumps. Of course, they'll get there before smaller pumps in number of pumps, but they'll get very hard to pump much quicker, sometimes to the point where you won't be able to move the pump.

Basically, figure out how hard you want to pull in terms of force and also how much pressure you want. P = F/A, so P = F/(pi*r^2). You can figure out about how wide of a pump you'd want from that.

Most bike pumps are about 1 to 1.5 inches in diameter. They're designed to be used standing up, and therefore likely require more force to use than a simple hand pump. On the contrary, water gun pumps are typically 5/8 inches. I'd imagine a good hand pump style thing would have to be 5/8 inches or maybe a little larger. You can trade pressure for volume sometimes. You don't need 100 PSI to get good performance. In fact, I'd be happy with 20 to 40 PSI in a WBL. The extended range goes wasted most of the time.

Personally, I'd have a larger air chamber and regulate it into a second chamber. Very few people have made a separate chamber WBL, which is a shame because it adds a lot of practicality to the design. Though, I don't think WBLs will be ever as practical as water guns due to the obvious differences, but they can be much more practical than they are right now.

If you're still going for a soaker-style pump, good luck getting that darn thing to seal... Well, even if it does seal, it'll probably be very stiff.

That'd be another reason not to use a homemade pump... some people have a lot of trouble getting them to seal.

My wooden pumps have sealed pretty well. In fact, I'd say they seal better than some manufactured water guns' pumps. My first few pumps weren't as successful.

What makes getting a pump to seal a lot easier to finding the right sized O-rings. The common #9 O-ring has an ID of 7/16 of an inch, so with a 1/2 inch dowel, you have to cut a notch in it. McMaster-Carr sells the less common 1/2 inch ID, 5/8 inch OD O-ring that you can use directly over 1/2 inch dowels. Not too many people know that.