Not there yet on the ball valve control, and missing oxygene
Yesterday night at the Electrolab was dedicated to two things: testing the larger gears for the ball valve to make up for the lack of torque of the stepper motor we are currently using, and welding with oxyfuel gas a part of a whipped cream siphon used to unload nitrous oxide cartridge and a standard plumbing link.
You can see in this video the result of the test with the larger of the two gears that Ryan had 3D printed in PLA and sent to me from Finland to France. Unfortunately, it is still not providing enough torque to rotate the ball valve.
I'm now thinking that we should seriously consider finding a stepper motor with more torque, rather than going for still bigger gears, which will in the end mean that a lot of time (and pressure in the combustion chamber) will be lost while the ball valve will be rotated painfully slow.
For the oxyfuel gas welding, I had purchased a (supposedly) brand new 60L oxygene canister to replace the depleted one in the blowtorch at the lab. However, as this video shows plainly, this canister turned out to be empty... quite a disapointment.
The bright side is that once again I learnt a lot about a technique I knew nothing about before that night. Not only was the welding metal to use discussed extensively (tin was abandonned in favour of silver, because of the high pressure to withstand), the way to weld was also discussed (pre-heating the 2 pieces to weld at 400°C beforehand?), but we also dipped the two parts to be welded together in chloridric acid to remove all copper oxides, which do not fix well to welding metal. And I also learnt about the basic security precautions, and appropriate configuration of the workplace, in order to weld efficiently and securely. My thanks go to our tech guru Zenos and to deputy tech guru Eric for guiding me through all this!