I am not someone who is very good at sitting still, so when I know I am going to have a few days off I like to have a project. One of my goals for this summer is to make a hot tub for the garden, a cedar wood tub linked to a wood fired water heater, and not as an elderly relation thought a large cauldron over a log fire. Both the hot tub and the water heaters are in themselves large projects, and one without the other is useless, however I worked on the theory if I made the water heater first it would be ready when I needed it, whereas if I made the tub first I can see myself trying to fill it up with the kettle, just so I can try it.

I have been champing at the bit with this one, real work has kept me very busy for weeks, but at least it gave me the time to organise all the materials first, sheet steel, and copper pipe not materials I usually have to hand.

In many ways having too much time to think this through, over many sleepless nights and bored days, created a design with a number of refinements, which probably made it far more complicated than it needs to be. In essence it’s a double skinned steel box, with a copper pipe bent into a coil. You light a fire inside and the fire heats up the water in the copper pipe, which exits into the hot tub, making use of what my academic daughters refer to as a temperature gradient, or as I know it “heat rises”.

 Once the outer panels are attached and a coat of paint applied it just looks like a very heavy steel box, and I feel vaguely  disappointed. The principles are so simple and the controls even easier, if you want the water hotter, you open the door letting in more air and put some more wood on the fire, if it’s hot enough shut the door and restrict the air flow, which reduces the fire. It’s too simple, there aren’t any pumps, or whirring motors, just a simple wood fire. I’ve slaved for three days to make this and all I have to show for it is a black box. Its not complicated enough, it needs knobs and dials with a Bluetooth connection as a minimum, and really it needs an app. How else can I impress the younger generation, and retain my street cred.

Alternatively I can just get on with the hot tub, but I might just find a way to fit in a dial somewhere.

thanks for reading

tom