Laser Etched Focusing Panel vs. Ground or Acid Etched

[Mike1234]

I spoke to Bill Moretz Photo today regarding the Chamonix 45N-1 he worked on for me (installed a Maxwell screen and timmed/shimmed to exact specs). I asked him his opinion regarding finely ground vs. acid etched focusing panels and he said the new laser etched ones are the best. He also said they're not very expensive.

I've never heard of laser etched focus panels and my searches picked up nothing. He's emailing the information to me tonight.

Anyone heard about these or is there any interested in this?

[Steve Smith]

Anyone heard about these or is there any interested in this?

I have not heard of this but at work, I do have a laser cutter which can etch so I think there will be some experimenting going on soon!

I would be interested in seeing the information you get if that is possible.


Steve.

[Mike1234]

Might be a new business for you, Steve.

[nick mulder]

I'll make you a bellows - you make me a 11x14" laser etched GG

deal ?

[Mike1234]

How about you, Nick, making me a replacement Toyo 810G bellows... and you, Steve, making me an 8x10 laser etched focus panel? I'll not charge either of you a single penny.

Hey, I just realized one could easily add a grid pattern and/or clear aerial focusing holes with little/no extra effort... or clear corners that don't need to be nipped!!

[lilmsmaggie]

I'm assuming you are discussing etching the ground glass panel. If not, then you can ignore the information below.

Thought this excerpt from Wikipedia might be of interest:

Stone and glass
"Stone and glass do not turn gaseous very easily. As expected, this makes them generally a better candidate for other means of engraving, most notably sandblasting or cutting using diamonds and water. But when a laser hits glass or stone, something else interesting happens: it fractures. Pores in the surface expose natural grains and crystalline "stubs" which, when heated very quickly, can separate a microscopic sized "chip" from the surface because the hot piece is expanding relative to its surroundings. So lasers are indeed used to engrave on glass, and if the power, speed and focus are just right, excellent results can be achieved. One should avoid large "fill" areas in glass engraving because the results across an expanse tend to be uneven; the glass ablation simply cannot be depended on for visual consistency, which may be a disadvantage or an advantage depending on the circumstances and the desired effect."

Also, if the glass has a high lead content, it will retain too much heat for quality laser etching.

[Mick Fagan]

I have a LASER engraving machine, I also have a couple of attachments for engraving onto glass bottles, jars and drinking tumblers.

From what I can work out the LASER doesn't actually engrave, it melts the glass surface in a reasonably controlled manner.

You may have to be careful about the actual content of the glass itself and also the amount of air trapped in the glass during manufacture. I have found that quite thin glass has a definite tendency to crack, which we have put down to trapped air expanding.

My engraver is equipped with an air assist facility, I find that switching over to Carbon Dioxide instead of pumped air, does seem to reduce cracking with thin glass.

Thin glass to me, is anything under 3mm, usually 2.2mm to 2.5mm.

I'm not sure if the glass could stand the heat from the whole surface being etched, whereas engraving lines either in a squared manner, or a design seems to be alright.

Any thoughts Steve?

One way to find out

Mick.

[Mick Fagan]

Hmmm, just read the reply before mine, yep been there done that with very expensive crystal glasses with a high lead content, they explode.

Well they crack first, usually a few minutes after coming off the machine, then all of a sudden one hears a crack and they shatter into an expensive pile of shardonay!

Mick.

[bdial]

Hmmm, just read the reply before mine, yep been there done that with very expensive crystal glasses with a high lead content, they explode.

Well they crack first, usually a few minutes after coming off the machine, then all of a sudden one hears a crack and they shatter into an expensive pile of shardonay!

Mick.

Sounds like it must be an impressive sight!

[Mike1234]

I haven't received an email from Bill Moretz yet but I think he's been having email server issues. I'll call him again tomorrow to get the contact info telephonically. In the meantime if one of you brave souls tries it please be careful.