I has been playing a lot with another small zapper selling also without copper tubes, the MZ5.
I have tried almost anything as electrodes.
Copper tubes are very convenient. Feet plates are more expensive and bulky, but give even better results (More area).
But in case of “emergency”, anything from a fork, metal knife, set of keys or electrical wire will help improve the zapping session. In any case, you should wrap your metal with wet paper or non-tinted tissue, to avoid a direct contact with the unknown metal. Making more wraps or using tap water (or both) will decrease the current. Using salty water solution will increase the current.
Use the method who gives you the maximum current, with comfort.
If needed, you can also play with time, increasing the 7mn time to make your zapping more “strong”.
Note: As soon as you see a greenish tint on your towel (copper chloride - toxic), replace them.
I don’t like the idea of using bare metal alloy (including stainless steel) with electricity on the skin, but the “Terminator” has been using pennies for a long time. Good or Bad?
Extract from Mr Don Croft site (Terminator)
“The other metal in pennies besides copper is zinc. When one inadvertently wears the copper off the penny by using an abrasive cleaner (my instructions specify the use of a non-abrasive cleaner) the zinc is exposed.”
Coming back to improvised electrodes
Electrical copper wire is pure to 99% or better, and is cheap and easy to find anywhere.
Copper tube used by plumbers on drinkable water is pure to 99.5% or better, and is also very common.
A piece of tissue or paper kitchen towel soaked in salty water and wrapped around the feet or hands (be sure it is always wet) has been used on the outdoors with good results against a sudden cold (20mn_On, 20mn_Off, 3 to 5 times)
The main disadvantage of your zapper is its simplicity (no even a ON-Off switch).
Its main advantage (outside its price) is also its simplicity and small packaging.
When you will be convinced of the zapper’s effect, you will probably buy a bigger one, but keep your actual one handy and operational : It is also and outstanding backup zapper you can carry in your pocket anywhere, and with improvised electrodes, it could become a lifesaver.