Most artists doing lampwork use a mixture of oxygen and propane. Some use just propane alone which produces a cooler flame. Some use MAPP gas, which is a mixture of methacetylene (CH3C2H) and propadiene (CH2CCH2) with traces of other gasses added as ‘stabilizers’. MAPP gas produces a hotter flame than propane alone, but less than oxy-propane. Popular torch brands are the Hot Head (cheap, portable, uses MAPP gas) and the Minor burner (oxy-propane, industry-standard, but more expensive)

For a 2-mirror system, it’s important to note that the closer to the apex where the two mirrors meet, the more accurate the reflected image. While earlier scopes had a round eyehole in the center of the scope end, many later scopes have incorporated a teardrop-shaped eyehole, which enables the viewer’s eye to get closer to the “sweet spot”, hence creating a more symmetric image.

A common method is to use ultraviolet (UV) glue to seal the acrylic chamber top and bottom. Then the side of the chamber is tapped to accept the threads of a grub or set screw. The chamber is filled with liquid, and then the thread of the screw is coated with UV glued and screwed into the chamber, sealing in the liquid.

Kaleidoscope artists each have their own methods. Some foil and solder the edges, some use hot glue or silicone, some use masking tape. The main objective is to firmly hold the mirrors in a fixed position in a manner that will withstand jarring, bumping, dropping(!), etc.