You’ve likely seen an X-cube, a dichroic prism used to split light into its constituent colours–you know, those fun little cubes you get when tearing apart a broken projector. Have you considered that the X-cube need not be a cube for its entire existence? [Matt] at “Matt’s Corner of Gem Cutting” on YouTube absolutely did, which is why he ground one into a 216-facet disco ball.
That’s the hack, really. He took something many of us have played with at our desks thinking “I should do something cool with this” and… did something cool with it that most of us lack the tools and especially skills to even consider. It’s not especially practical, but it is especially pretty. Art, in other words.
The shape he’s using is known specifically to gemologists as “Santa’s Little Helper II” though we’d probably describe it as a kind of isosphere. Faceting the cube is just a matter of grinding down the facets to create the isosphere, then polishing them to brilliance with increasingly finer grit. This is done one hemisphere at a time, so the other hemisphere can be safely held in place with the now-classic cyanoacrylate and baking soda composite. Yes, jewelers use that trick, too.
We were slightly worried when [Matt] dumped his finished disco ball in acetone to clean off the cyanoacrylate– we haven’t the foggiest idea what optical-quality glue is used to hold the four prisms of an X-cube together and were a little worried acetone might soften the joints. That turned out not to be an issue, and [Matt] now has the most eye-catching sun-catcher we think we’ve ever seen.
We actually have seen suncatchers before, though admittedly it’s not a very popular tag around here. The closest build to this one was a so-called “hypercrystal” that combined an infinitiy mirror with a crystaline shape and dicloric tape for an effect as trippy as it sounds.
We also featured a deep-dive a while back if you want to know how these colourful, hard-to-pronounce coatings work.
You’ve spelled Dichroic several different ways- all of them wrong.
Dichoric, dicloric?
I fear that the spellchecker has fallen and can’t get up.
(Delete this comment as you see fit)
To clarify the above comment: It’s “dichroic”. “di” meaning two, “chro” as in “chrominance” or “chroma”.
(likewise)
The Latin equivalent is “bicolor” – not fancy enough, lacks the Greek je ne sais quoi.
I’m really glad to find out that it was not a lack of knowledge of the English language that made me read it as “Dichroic” at first, and then thinking: “No, it actually says ‘Dichoric’, multiple times, maybe it’s a word I didn’t know yet?”, but then finding out on Google that the word “Dichoric” does not exist in the English language.
Wiktionary, the free dictionary
dichoric
dichoric. Misspelling of dichroic. Anagrams. diorchic, dichroic
:)
It should be written “dichroic”.
It should be spelled ‘dichroic’ as in two color. Because it behaves differently with different colors. The title and many places in the text need to be updated.
Spelling aside, that’s a really cool idea. I’ve several of these prisms in my junk box, but I don’t think gem faceting is something to take up on a whim.
Is there a good guide to the safety precautions for it? Avoid fibrosis seems like an important one – I assume the water keeps the dust down but what’s the cleaning and disposal protocol?
When I was gem cutting, we kept everything wet, washed the (moist) grinding powder off everything and bagged it while it was still wet. I’m sure newer, OSHA-approved places do something better, but this was a small jewelry studio workshop in someone’s back yard. I will say, the saw in particular threw powder-filled water just EVERYWHERE and it wasn’t easy to keep that clean, even with a guard around the blade except for the part where you were cutting. (And much worse if you were dicing stone because then you had the whole upper half of the blade exposed so it went straight up and spattered the ceiling.) The grinding and polishing stations were a lot easier to keep clean.
In which projectors can an X-cube be found?
The expensive ones that claim 3 DLP or 3 LCD modulators. The dichroic cube is the element that combines the three R, G, B monochrome images into a RGB projected image.
All over on Ali, especially the B-rated that have slight chips on the edge are cheap (at least the small ones)
Oh, no! A new, unneeded hobby is beckoning!