Obstacles and opportunities. That pairing has been the theme of this project. I couldn’t find an ultralight chimney kettle, so I decided to make one. The pieces of aluminum bottles that I hacked up to make one were too thin to weld, so I looked into this “metal spinning” thing. The shops I sent design plans to couldn’t offer the parts in the thickness I needed, so I learned how to do it myself.
In this case, I went to the anodizing shop and they told me the kettle needed another hole in order for the anodizing chemicals to fill and drain properly. This gave me the chance to incorporate a safety feature that I had wanted to include, but hadn’t been able to figure out how to – a pressure release valve.
A long-standing problem with chimney kettles has been that, as a designer, you can either include a stopper and risk someone forgetting to remove it while boiling water – causing a dangerous buildup of pressure in the kettle – or you can nix the stopper and make it so the vessel can no longer carry water. The solution is creating a way for the kettle to remain water-tight under normal conditions, but release pressure if it becomes to great.
* I should note that this valve won’t make it safe to heat the boiler with the stopper in. It is simply meant to lessen the possibility of a catastrophic failure.
As I say in the video, this is just a rough version. The final valve will match the stopper material, have smooth edges, and be located directly opposite the pour spout on the top of the kettle. It’s a simple solution that was partially inspired by the nossles of no-drip ketchup bottles, and not only takes advantage of what would otherwise simply be a useless hole, but also makes the kettle safer.
Update: I’ve decided not to include the pressure release valve in the Boilers after all. Some of the discussion of this feature lead me to worry that folks might try to leave the stopper in while boiling, relying on the valve to release pressure – this WOULD NOT BE SAFE (for a number of reasons that can’t be reasonably controlled). To avoid any confusion, I’m leaving it out, and keeping the clear warning to remove the stopper before use.