Opening your water gun
Written by Silence
Last updated on 2008-07-28
Opening a commercial water gun is required for most repairs and modifications.
Using a small Phillips-head screwdriver (jewelers' screwdrivers are the most common, but screwdrivers with larger grips for more leverage are preferable), unscrew each screw holding the halves of the case together.
It is fairly important to keep track of the screws (there may be multiple types) for reassembly after repair or modification of the water gun. Simple sticky tape can be used to hold each screw in place on the case plate itself, next to the appropriate hole.
Still, a water gun can easily function with missing case screws. Soakers can often be reliably held together with only a few screws, but it is still advisable to keep track of each item.
When opening water guns with tracked pumps, the pump handle must be removed before the remainder of the gun can be opened.
The bulk of this article covers troubleshooting of various issues that often surface while opening a water gun. Most problems have multiple solutions, but only the easiest are detailed here.
Often, certain screws holding a water gun's shells together may be tight or rusted. A larger screwdriver provides an easy solution, but in cases where it is too large to reach or fits the screw, one could try using a wrench to increase the leverage with a smaller screwdriver. Finally, if the screw can be reached, the use of a drill in reverse and a Phillips-head drill bit may work.
If a screw is very rusted or the head has been damaged by attempts to unscrew, the only option may be to eliminate the screw altogether. A powerful drill, with a drill bit approximately the size of the screw's threads, can easily drive straight through the screw. Naturally, though, the case cannot reliably be held together at that point again.
Certain sections of the case, such as the circular pump "cap" that holds together the case at the pump tube, are often fitted or glued on tightly.
Note that some parts that appear to be glued initially may be threaded instead. Try unscrewing pump caps to see if it will save you any time.
If the case is glued in certain parts, run or pry a screwdriver down the length of the glued section to separate the two halves.
The least damaging workaround involves prying off the piece using a flathead screwdriver or a similar tool. Progress from smaller to larger screwdrivers as the gap between the tight piece and the rest of the water gun widens. Pry at different points on the seam in order to remove the piece evenly. Heating a screwdriver to melt the glue has been reported to help prying as well.
If no progress occurs through prying (most common when case has been glued), the only solution is to cut through the otherwise immovable section. While cutting along the seam and removing the piece entirely is an effective solution, it does affect the aesthetics of the water gun. A better solution is to cut a new line straight down the glued piece, effectively extending the seam between the halves of the case.
While cutting is most often done using a metal band saw or a hacksaw, such bulky tools may not work as other parts of the water gun may get in the way (as happens when cutting a seam through the CPS 4100's pump cap). In such cases, the plastic piece may be split using a hammer-and-chisel approach or cut with a smaller tool.
When cutting, be sure not to damage any parts of the water gun you do not intend to cut. For example, when cutting through the pump cap on a CPS 2700, be sure to stop cutting and adjust your angle when you get deep enough to hit the pump rod. However, some some guns such as the CPS 2100 and CPS 4100 where the pump is tracked, the pump cap can be sawed off completely with no damage to other pieces.
With the water gun now open, you may clean, repair, or modify the internals. When reassembling the soaker, you should not need to overtighten the screws, as you may want to reopen it later.