Two-Stroke Pump

[isoaker_com]

Originally Posted by SilentGuy

in non-tracked pumps, the pump shaft will take up a constant fraction (due to the area) of the volume of one chamber, though that is not the case with tracked pumps

The problem lies in this statement. Why should a non-tracked pump-system be any different than a tracked pump-system? To turn a non-tracked pump into a tracked one, simple mount a rod extending from the front of a soaker and attach a guide onto the pump. Now it's tracked without changing any other aspect of the pump. To turn a tracked pump into a non-tracked one (for a stock soaker), simply break off enough of the plastic tracking so that the pump is free.

Pump diameter affects force need to pump the volume. Pump tracking helps keep things straight and can, perhaps, reduce chance of damaging the pump if dropped. Otherwise, tracked or non-tracked pumps are equal.

That said, I've never enjoyed using two-stroke pumps on soakers. The out-stroke resistance, while allowing the PC to fill, feels odd and ends up slowing down total pumping speed (not to mention that I have a harder time maintaining aim if there is more resistance on the out-stroke).

[Silence]

@ st_jimmy: Adding the O-ring you're referring to might actually be easier than normal, mainly because you don't need to use electrical tape to stabilize the O-ring. However, there might be some precision involved when cutting a hole in the O-ring (though maybe a female threaded reducer would also work).

@ iSoaker.com: I have been referring to the Duxburian- and, in this case, the m15399-style tracked pump. If you look at the diagram that m15399 submitted at the SM thread he linked to, you'll notice that the design is quite different; namely, it has two Duxburian-style tracked pumps back-to-back and using the same pump shaft, grip, and track. However, you do make a good point, as what you described is similar to that which is used in commercial soakers; in fact, I've been thinking of having my pump grip come off the pump shaft and curve upward, where it has a loop that surrounds the barrel. This vertical part of the pump grip will allow me to apply more outstroke force, and for my use, stabilization is only a secondary concern.