How thick is light bulb glass?
February 22, 2017 5:27 AM   Subscribe

I'm modeling a standard, incandescent light bulb (the A60, here). Assume 60 watts, if that makes a difference. I'm pleased with the general result, but would like the glass thickness to mirror reality. I've visually estimated it, but oddly can't find any reference online to how thick it is by standard. I'm currently using 0.2 mm. What should it be?
posted by gilrain to Grab Bag (7 answers total) 2 users marked this as a favorite
 
This paper has measured A19 (imperial version of the A60) bulbs at around 0.5 - 0.8 mm thick. Hurray for scientists exploding lightbulbs.
posted by samj at 6:02 AM on February 22, 2017 [3 favorites]


Google searching results in non citable sources at either .7mm .8mm or 1.2mm.

My gut would've been in the .7mm range apropos of nothing other than like experiences with pencil leads etc. .2mm is realllly thin. For comparison a chicken egg shell is appx .3mm and to my, again gut, feeling, is thinner by some margin than light bulb glass.
posted by chasles at 6:16 AM on February 22, 2017 [1 favorite]


ok damnit. this was bothering me yes, that fast. so i went and broke a dead standard GE 60 watt bulb new out of package (i hope you're happy!)

i used a reasonable quality vernier caliper with a stated accuracyof .07mm and a resolution of "hundredths of mm". i measured a .7mm pencil lead and got values between .64 and .72mm.

the bulb, having a radius, gave some variability in measurement. I measured something like 40 or 50 places from the main globe of the bulb and i consistently got values between .55mm and .65mm. there were a few outliers to the thinner side, nothing thinner than .48mm. i would guess that the true median value and what felt like the most real measurement that repeated the most often was .64mm

so i would say .6mm is your definitive answer.
posted by chasles at 6:26 AM on February 22, 2017 [43 favorites]


Excellent hands-on detective work, chasles! Thank you so much. It's interesting how much thicker that is than my visual impression. I feel my scene currently looks fairly real... I can't wait to see how thicker glass influences things!
posted by gilrain at 6:45 AM on February 22, 2017


Just FYI, the proper tool for measuring the thickness of light bulb glass is a ball anvil micrometer.
posted by Bruce H. at 8:04 AM on February 22, 2017


Not quite finished with the materials, but here's the scene with 0.6 mm thick bulbs. Thanks again!
posted by gilrain at 2:23 PM on February 22, 2017 [1 favorite]


True, a ball anvil micrometer would be ideal for a curved surface smaller than the radius of the ball itself but the instantaneous slope of the curve at any point was near enough to null as to be immaterial. Also, i don't have a micrometer. I do have vernier calipers. Hence, that was the correct tool (being the one i have)

Thats a totally cool scene!!
posted by chasles at 8:09 PM on February 22, 2017


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