Various convection vaporizers claim "glass on glass" design or construction. The term is rarely, if ever, defined and there appears to be no consistency in use of the term. What exactly does this mean, in terms of marketed vaporizers? What should it mean -- what do you assume it means? And what hazards might "glass on glass" or other glass used within heater units entail?
"Glass on glass" does not appear to literally mean that glass is coating or covering glass. Is this term really referring to all-glass air flow -- the air only ever contacting glass within the heater unit -- with only glass or glass-coated components used in the heater to handle air flow? Or, does "glass on glass" refer to the use of ground glass (Gong-type) joints, such those used to connect most whips to many desktop vaporizers (plugging glass onto/into glass)?
Does "glass on glass" mean use of borosilicate, Pyrex or similar high temperature- and temperature change-tolerant glass? What types of glass are appropriate and inappropriate for use in vaporizer heaters? What types are used?
"Glass on glass" (whatever it really means) construction certainly appears to be held in high esteem, particularly in terms of taste. This is understandable, presuming that we're referring to air flow though the heater only ever contacting glass.
But is "glass on glass" safe in the long-term -- will these vaporizers fail (glass fracture inside) after years of use? What about stress cracks? Theoretically, in any solid, particularly one that is brittle (like glass) and subjected to rapid temperature changes (such as rapid cooling from room temperature air flowing over hot glass), cracks are inevitable; along with cracking at interfaces between glass and metal, ceramic or any other material (with different rates of thermal expansion and contraction). Cracks might even be expected, particularly in stressed areas, such as curved glass areas, anchoring points, joints, insufficiently immobilized portions of glass, etc. I realize that temperature swing insensitivity is why borosilicate, Pyrex, etc., glass is used. But do these materials remain unaffected after years of use, wild temperature swings, combined with the vaporizer being moved, maybe even being dropped? How do "glass on glass" or glass coating of heating elements and metal heat exchangers deal with thermally-induced stresses, the different expansion and contraction rates of the glass and metal or ceramic, and theoretically inevitable cracking at the interface where glass covers the heating element?
If you presume "glass on glass" or extensive use of glass is safe, are you presuming that thick glass is being used? How thick must glass be to be safe in vaporizer heating units? What about thin glass coatings, such as might be used on heating elements and air flow paths in some "glass on glass" or other glass vapor path vaporizers?
If glass inside a vaporizer heating unit breaks, how can you tell (other than happening to hear it)? What if you don't notice it's broken or the breakage is just too small (but easily inhaleable)?
I realize many "glass on glass" vaporizers work very well. But will they fail (glass break), if only many years from now, and will this failure be serious health hazards (glass chip inhalation)? [Personally, this is a concern and seems reasonable]. I am just asking questions and not criticizing or calling any "glass on glass" or other glass-using vaporizers unsafe or unworthy. But in looking over various vaporizer Web sites, most are very vague on what "glass on glass" actually means in terms of their construction; and as far as I can tell, many questions about use of glass within convection vaporizer heating units remain unanswered or not yet discussed on FC.
"Glass on glass" does not appear to literally mean that glass is coating or covering glass. Is this term really referring to all-glass air flow -- the air only ever contacting glass within the heater unit -- with only glass or glass-coated components used in the heater to handle air flow? Or, does "glass on glass" refer to the use of ground glass (Gong-type) joints, such those used to connect most whips to many desktop vaporizers (plugging glass onto/into glass)?
Does "glass on glass" mean use of borosilicate, Pyrex or similar high temperature- and temperature change-tolerant glass? What types of glass are appropriate and inappropriate for use in vaporizer heaters? What types are used?
"Glass on glass" (whatever it really means) construction certainly appears to be held in high esteem, particularly in terms of taste. This is understandable, presuming that we're referring to air flow though the heater only ever contacting glass.
But is "glass on glass" safe in the long-term -- will these vaporizers fail (glass fracture inside) after years of use? What about stress cracks? Theoretically, in any solid, particularly one that is brittle (like glass) and subjected to rapid temperature changes (such as rapid cooling from room temperature air flowing over hot glass), cracks are inevitable; along with cracking at interfaces between glass and metal, ceramic or any other material (with different rates of thermal expansion and contraction). Cracks might even be expected, particularly in stressed areas, such as curved glass areas, anchoring points, joints, insufficiently immobilized portions of glass, etc. I realize that temperature swing insensitivity is why borosilicate, Pyrex, etc., glass is used. But do these materials remain unaffected after years of use, wild temperature swings, combined with the vaporizer being moved, maybe even being dropped? How do "glass on glass" or glass coating of heating elements and metal heat exchangers deal with thermally-induced stresses, the different expansion and contraction rates of the glass and metal or ceramic, and theoretically inevitable cracking at the interface where glass covers the heating element?
If you presume "glass on glass" or extensive use of glass is safe, are you presuming that thick glass is being used? How thick must glass be to be safe in vaporizer heating units? What about thin glass coatings, such as might be used on heating elements and air flow paths in some "glass on glass" or other glass vapor path vaporizers?
If glass inside a vaporizer heating unit breaks, how can you tell (other than happening to hear it)? What if you don't notice it's broken or the breakage is just too small (but easily inhaleable)?
I realize many "glass on glass" vaporizers work very well. But will they fail (glass break), if only many years from now, and will this failure be serious health hazards (glass chip inhalation)? [Personally, this is a concern and seems reasonable]. I am just asking questions and not criticizing or calling any "glass on glass" or other glass-using vaporizers unsafe or unworthy. But in looking over various vaporizer Web sites, most are very vague on what "glass on glass" actually means in terms of their construction; and as far as I can tell, many questions about use of glass within convection vaporizer heating units remain unanswered or not yet discussed on FC.
The Injector glass is really thick and if some little breakage occours you can see it!
