Thread from the WWn Wiki - originally developed by iSoaker, Martianshark, and Andrew
1.1 Spherical Modifications (K-Mods)
1.2 Cylindrical Modifications (Colossus)
2 Theory and technique
3 Advantages and Disadvantages
4 Related Modifications
5 External Links
Elastic pressure power modifications (EPPM) include any change or alteration to the stock elastic chamber of a water blaster. Most commonly, these modifications are undertaken with the goal of increasing the elastic tension of the chamber, which leads to increased pressure on the water held within. Many of the theories and techniques of elastic pressure power modifications can be directly applied to constant pressure homemades.
Typically, these modifications are split into two groups based on the physical shape of the elastic pressure chamber.
 Spherical Modifications (K-Mods)
Spherical modifications, known colloquially as "K-Mods", are a form of EPPM targeted at water blasters with spherical elastic pressure chambers. A few examples of water guns that could be modded include the CPS 1000, CPS 2100, and Vanquisher.
 Cylindrical Modifications (Colossus)
Cylindrical modifications, known colloquially as "Colossus Mods", are a form of EPPM targeted at water blasters with cylindrical elastic pressure chambers. A few examples of moddable blasters include the Super Soaker CPS 2500, Flash Flood, and Hydro Cannon.
 Theory and technique
In both cases, increased power is acheived by increasing the thickness of the elastic material used in the pressure chamber. This is accomplished by layering a thin rubber material uniformly over the surface of the original elastic material. A dedicated material can be used for this purpose, or common everyday items can be substitued. For example, party balloons may be used for spherical modifications while sectioned bicycle innertubes may be used for cylindrical modifications.
 Advantages and Disadvantages
There are several advantages to elastic pressure power modifications. The first is increased power which translates directly into increased output. Depending on nozzle configurations, some users may experience increased range due to this type of modification. Another advantage is reversability; because these modifications due not inherently rely on the destruction or replacement of any portion of the original water blaster they are easily reversible. As such, they offer a good foundation for beginners who may lack the knowledge or confidence to attempt more advanced procedures.
EPPM are not without disadvantages, some of which can be solved through related modifications. The increased tension on the pressure chamber will result in a premature activation of the pressure relief valve. A blaster with no modifications other than an EPPM will reach its maximum pressure with less pumps. This results in decreased effective volume, as less water is stored in the chamber before being vented back into the reservoir. This will translate to decreased shot time for most water blasters. As such, a pressure relief valve removal or disablement is a common sister-modification to an EPPM and allows the user to maximize the benefit of performing an EPPM.
 Related Modifications
Pressure relief valve disablement
Pressure relief valve removal
Stream laminations modifications
 External Links
K-Mod - Super Soaker Central - http://www.sscentral.org/mods/kmod.html
Colossus - Super Soaker Central - http://www.sscentral.org/mods/colossus.html