I finally got around to testing the Simplex No4 Kettle (a new one just arrived today) to test its efficiency and speed using an old Coleman Gas Stove and Gasmate adapter.


Simplex No4 Copper Kettle


Simple No4 Copper Kettle Heat Exchanger

The Simplex No4 Kettle is all Copper Construction (beautifully chromed outside with Nickel plating inside) except for the kettle lid top and handle, which is apparently made from turned ebonised beech wood and is designed to be used with gas burning stoves due to the design of the heat exchanger system. The Kettle weighs 1048 grams or just under 37oz. The Capacity is stated at 1.7 Litres or 57 fl oz. Overall the kettle has the look of a very durable and quality well made and designed product with excellent ergonomics i.e. it is very easy to pour boiling water into smaller containers. The ambient temperature inside was around 18C under controlled conditions.

I tested the kettle with around 38 fl oz of water (1.125 litres) of quite cold water at around 3-5 C. I measured the weight of a new UN2037 Butane gas Cartridge at 325g then set about to boil the water in the Simplex No4 Kettle. Boil time with the old Coleman Stove was around 7-8 minutes, which is excellent considering the limited heat output of the old Coleman and the cheap butane gas cartridge. The Kettle will also indicate when the water has reached a rolling boil. A whistling sound that many younger folks may have not heard in their lifetimes.


Old Coleman Stove and Gasmate Adapter.

I measured the weight of the gas cartridge once more and subtracted it from the initial weight and found that boiling just over 1.1 litres of water consumed around 14 grams of fuel. Fuel efficiency for the Simplex Kettle was again excellent i.e a single UN2037 Butane gas Cartridge (220 gram net weight of fuel) should allow 17.6 litres of very cold water to the boil. This is getting near the same efficiency as an MSR reactor stove. Not bad for 100 year old technology.

The Simpex No4 is great durable piece of emergency kit, which should last a lifetime but has unfortunately has been relegated to my domestic backup gear list as my domestic stove is currently all electric and so is my current domestic Kettle (a more convenient faster boiling electric kettle).