The copper and brass burner weighs 24 kg (53 lb). It has a large brass lifting handle at each end. I’ve carried one 3 km (2 miles) down to Taieri Mouth to where the river meets the waves (we just rolled and floated the tub). I did have to put it down to rest a few times! However two people can carry it easily between them for long distances.

It is extremely robust. The cast brass door is 5-6mm (1/4inch) thick; the internal copper skin is 1.2mm thick and corrugated for huge extra strength.

We think it will last for 200 years. That's not hype - my Dad's copper Thermette is now over 80 years old and going fine. The Thermette is an iconic Kiwi water heating kettle with a fire up its middle, invented in the late 1930s. It was the inspiration for the Kiwitub burner - which is essentially a big mutated Thermette lying on its side with extra efficiencies built in.

The Kiwitub burner is a lot tougher again. And copper doesn't rust, and it'll handle expansion and contraction due to heat pretty much forever. (Stainless steel won't.)

So we think it's an heirloom.