It is, after all, a major design -- my magnetometer. I am slowly rebuilding the circuit board at the moment, as the prototype is too tangled, and therefore too fragile. After I have rebuilt the board, I shall need to house it. This is a special challenge. I have two sensors, which if perfectly aligned, cancel out the earth's magnetic field. In other words, the machine is immune to planet earth -- and many other things besides. But if one turns one of these sensors just one-tenth of one degree within the earth's magnetic field, this is more than enough to trigger the magnetometer. This is a movement less than the width of a human hair. Therefore the two sensors must be absolutely rock solid. For this, I have a length of heavy asbestos pipe ready, for mounting everything. OBSERVATION: But I need to think on what to do if, say, one of the controls gets damaged. How do I get inside a heavy asbestos pipe to fix something? I may create some weak points in the pipe, to be able to break it open.