For those concerned with loose Solo stems, rather than an O-ring, you might consider PTFE/Teflon (plumbing joint sealing) tape wrapped around the stem (or silicone, aluminum foil, any high-temp. resistant tape/foil. Basically, wrap the tape, insert in vaporizer and make a custom-fitting bushing/gasket/seal. It's simple, cheap, quick, harmless, and fully removable and adjustable.
I cut a piece of Teflon tape, wet my fingers and the tape with some diluted glue from a common glue stick (non-toxic, plus any exposed can be wiped off), wrap the wetted tape around the stem such that part of the top will be exposed/visible (so most of wrapping will be within the heating chamber), and slide this into a cool Solo (or other vaporizer being used), and then remove it (making sure to twist it on and off so you don't wrinkle the tape). If lucky (or on a 2nd try, with handling Teflon tape not so easy), the tape should have compressed where pushed into the vaporizer, forming a tight(er) seal, with a lip of uncompressed tape at the top. The tape congeals into a robust unitary piece of plastic, particularly after being baked by your vaporizer. If you want a tighter seal, now or in the future, just add more tape.
For me, this was much simpler than installing an O-ring in my Solo. The same thing (wrapping, forming a custom gasket) could also be done with any Gong or other vaporizer path joint/seal.
Note, PTFE/Teflon tape) comes as just thin Teflon and is normally used without any adhesive and naturally sticks/congeals to itself, so you can simply try this without using any glue (and it may even last a long time). Otherwise, most any high-temp.-resistant tape or foil could be wrapped or very lightly glued around the stem and used to form a gasket/seal. Common white (pure virgin PTFE/Teflon) plumbing joint sealing tape is cheap ($1-$2 at most/roll) and safe. It has long been used for sealing plumbing joints (water supplies), and for baking and cooking, with vaporization of Teflon not an issue at wimpy vaporizer temperatures (with concerns starting say around 800˚F or multiple 100s of degrees higher than vaping temperatures).
I cut a piece of Teflon tape, wet my fingers and the tape with some diluted glue from a common glue stick (non-toxic, plus any exposed can be wiped off), wrap the wetted tape around the stem such that part of the top will be exposed/visible (so most of wrapping will be within the heating chamber), and slide this into a cool Solo (or other vaporizer being used), and then remove it (making sure to twist it on and off so you don't wrinkle the tape). If lucky (or on a 2nd try, with handling Teflon tape not so easy), the tape should have compressed where pushed into the vaporizer, forming a tight(er) seal, with a lip of uncompressed tape at the top. The tape congeals into a robust unitary piece of plastic, particularly after being baked by your vaporizer. If you want a tighter seal, now or in the future, just add more tape.
For me, this was much simpler than installing an O-ring in my Solo. The same thing (wrapping, forming a custom gasket) could also be done with any Gong or other vaporizer path joint/seal.
Note, PTFE/Teflon tape) comes as just thin Teflon and is normally used without any adhesive and naturally sticks/congeals to itself, so you can simply try this without using any glue (and it may even last a long time). Otherwise, most any high-temp.-resistant tape or foil could be wrapped or very lightly glued around the stem and used to form a gasket/seal. Common white (pure virgin PTFE/Teflon) plumbing joint sealing tape is cheap ($1-$2 at most/roll) and safe. It has long been used for sealing plumbing joints (water supplies), and for baking and cooking, with vaporization of Teflon not an issue at wimpy vaporizer temperatures (with concerns starting say around 800˚F or multiple 100s of degrees higher than vaping temperatures).