Pumping Gunge, Goo and Slime
The pumping of viscous fluids such as slime can be quite problematic, and won’t be particularly easy to achieve with common pumps, on this page I will cover possible options that may be available to you if you want to pump goo.
Most commonly available electric and petrol pumps (submersible pumps, windscreen washer pumps, pool pumps) are centrifugal types.
Centrifugal pumps consist of a disc with vanes on, known as an impellor, rotated by the power source (motor, engine etc.) The inlet is arranged at the centre of the disc and the outlet at the edge. This type of pump is simple to manufacture and efficient for fluids such as water, but generally does not work effectively with more viscous fluids, and needs priming; prefilling with the fluid being pumped to get them started. Many centrifugal pumps also do not cope well with lumps- this is dependent on the impeller and case design. You may have some success if your slime is very runny, or using a pump intended for dirty water use (such as a submersible pump).
A notable example of where a centrifugal pump is used, is ‘Life in Color’ to pump paint over the people visiting their events. A good image of this can be found in their Flickr photostream; Life in Color From their photostream it can be seen that they mix in water to keep the viscosity down, as well as ensuring that their paint is well mixed.
There are a number of other types of pump available that are more suited to viscous fluids, but are less widely available;
These use a reciprocating piston (like a bicycle pump or stirrup pump) and can achieve very high pressures, but often at low flow rate. They are used in items such as pressure washers. I am not aware of any readily available powered pumps of this type suitable for use with gunge, but you could use some of the hand pumps of this type that are available (some water pistols are of this type).
These consist of a pair of ‘gears’ meshed inside a case- they are common for oil pumps in car engines and hydraulic systems amongst others. I am not aware of any readily available pumps of this type suitable for use with gunge.
This type uses a tube squeezed by rollers to move fluid. They can be very accurate at dispensing a set volume of liquid so are commonly used in medical and laboratory equipment, as well as in dosing chemicals in applications such as commercial dishwashers and aquariums. They are typically small, and move very low volumes of liquids (up to 100mls/min range). I am not aware of any readily available pumps suitable for use with gunge in any usable volume.
Peristaltic Pump- Complete and with cover removed
A diaphragm pump works by the movement of a rubber diaphragm inside a pump chamber. This can either be driven mechanically by hand, motor or engine, or by use of a gas such as air or Carbon Dioxide. They are usually self-priming and to a certain extent can cope with particles/ lumps. In my opinion this type are most suited to the general pumping of goo. It is worth noting that by their nature the output of the pump tends to pulse, so they may not be suitable for an even flow. If they contain two chambers, they are double acting and do not suffer the pulsing anywhere near as much.
Small low voltage diaphragm pumps are commonly used in boats, caravans, RVs etc for pumping fresh water. These don’t appear to be particularly suitable due to their small size, similarly sized Carbon dioxide powered units are often used in drinks dispensing applications.
Electric and Carbon Dioxide Gas Powered Pumps
There are larger electric versions sold as marine shower or toilet drain pumps which are much more suitable for our uses, an indeed is what I use. Common makes include Whale and Jabsco.
Much larger units are available for industrial use such as pumping oils, chemicals and paint. These units are commonly air powered, and can move significant volumes of fluid, but come with a much higher cost. Typicallyy these are known as Air Operated Double Diaphragm pumps. These are what Nickelodeon use in their Kids Choice Award and Slimefest to move pump their slime.
Typical Air Operated Double Diaphraghm (AODD) Pump, a 3/8" Graco Husky, I use for pumping slime
An effective method of moving gunge in limited quantities is to use air pressure to pressurise an enclosure containing the gunge- the easiest method is probably to use a fire extinguisher. Many modern extinguishers use a Schrader valve to enable filling the air and so can easily be hooked up to a foot pump or compressor to refill. The output hose is usually fitted with a standard thread, and so can be easily swapped out with other output hoses. I have used this method on a number of occasions- It is particularly good when you need accurate control of timing, but are away from power. I have painted my extinguishers used for this purple so they are clearly not an active piece of fire fighting kit.
The quoted flow rates for a pump (volume pumped in set time, typically in litres or gallons per minute) are usually based on using water at a defined head (height the water is pumped up). Although manufacturers will usually publish tables or charts as to how the flow varies with head, flow rates will be significantly less than quoted for water when used with a more viscous fluid. It is worth bearing this in mind when selecting a pump, and indeed in carrying out trials.