Ive been trying to make a cloud chamber for a few days. I seem to have gotten most of the way there, but cant quite see any tracks, only mist. Im using isopropanol with cooling from salted water ice at -18-ish C. I have a metal radiator suspended in the ice as the bottom plate, a glass vase as the container, felt at the top soaked with 99.9% isopropanol and a led laser for ilumination. At the bottom of the container I see a layer around 15 mm thick of isopropanol condensati precipitating slowly. This seems to me to be mostly correct, and I have followed most online tips to ensure the best results, but I have yet to see a track. Any help would be much appreciated. Also I just noticed that over around 10-15 mins the mist starts to become less dense and eventually almost disappears. If I ventilate the container for a few seconds the mist quickly re-appears after that. Video of observation: https://photos.app.goo.gl/XmqVT1kfTfuumW5t8
I am not sure -18 deg C is enough. Maybe you should try dry ice. Maybe you should try to emulate other people's design. See also Near-room temperature DIY cloud chamber?