Stuff you SHOULD NEVER try to laser

[Mitchell Andrus]

It's about time to compile a "don't do this" list for the benefit of those of us who haven't yet tried and failed.

The big one: PVC

There are likely things that burst into flames, turn to goo, release harmful gasses, shatter, etc. How about it.....

Mitch

[Guy Hilliard]

High lead crystal (24%) tends to shatter when engraved, but low lead (5 - 10%) seems to work better than ordinary glass!

Tempered glass can cause no end of problems, when you break the surface it turns itself into little pieces. It may take 5 seconds or 5 weeks but it will turn into little tiny cubes. Note that sand carving seems to work well with tempered glass and I haven't a clue as to why.

UHMW is OK (not great) in thin sheets (< 0.032") but turns into a molten mess in thicker sheets making a mess much like melted wax.

Guy

[Bruce Volden]

I have not tried it but I have heard styrofoam is a no-no??!!Bruce

[Bob Belt]

Tho not a no-no, HDPE (high density polyethylene) is a tough cut. It to melts like wax. A better sub is ABS.
Bob

[Dave Jones]

Styrofoams are made from polystyrene, so I'm guessing it's not bad for the machine like PVC, which turns into hydrochloric acid. But the fumes from styrofoam are going to be fairly toxic (like many plastics).

These are guesses. I don't know.

[Joe Pelonio]

The front of a mirror, it will bounce the beam and engrave the underside of a glass top, or damage a lense.

Some varieties of polycarbonate cut nicely, others produce a bright yellow smoke which I have not been able to identify as harmful but it's a little scary.

Fingers and other human body parts, or small live animals.

[Mark Rios]

How about a piece of fruit? Could you laser a banana?

[Thomas Hempleman]

How about a piece of fruit? Could you laser a banana?

You could. But they're much better fried. :p

T.

[Lee DeRaud]

Fingers and other human body parts, or small live animals.How about large live...never mind. :eek:

[Barbara Buhse]

do you think if we lasered a peice of toast with a religious icon we could sell it on e-bay?

[Dave Jones]

I thought about doing that same thing.

[Lee DeRaud]

do you think if we lasered a peice of toast with a religious icon we could sell it on e-bay?Like what, a picture of Yoko Ono? :eek:

[Joe Pelonio]

Yes, a banana would work fine. I've done some fruit, leaves, and cheese. Produce wholesalers are lasering the date on fruit and vegetables now, and a big novelty item is a bean lasered with some nice words and planted in a tiny pot, so that when it sprouts it says something on it.

http://www.spoonsisters.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=47901

[Brent Brod]

do you think if we lasered a peice of toast with a religious icon we could sell it on e-bay?

I made an Elvis toast for a friend. She has it in her office/shrine. I was thinking if you "found" some Elvis toast on your plate at a diner in New Mexico, what a price it would command :D

[Pete Simmons]

A mirrored surface.... is there any real danger to the laser, lens, tube or mirrors?

The beam has been through all those items on its way to the target, so can a reflection really do any damage?

[Mitchell Andrus]

I guessing any beam bouced back towards the lens would be as unfocussed as the beam that came through it the first time, so I think i'd be OK.

But....

You try it first and ley us know what happens. ;)

Mitch

[Bruce Volden]

Wive's tales??? I've engraved many a mirror, both sides! Still have the original lens-11+ years old now. I have replaced a couple of bounce mirrors when the coating flaked off for whatever reason. I'm thinking that when the focused beam strikes the reflective surface of a mirror being engraved, the energy of the beam has already done it's "work" in ablating the surface thereby nullifying any reflection??? Doesn't that sound smart.
That 6 years of high school is really paying off.:D :D



Bruce

[Rodne Gold]

The mirrors in your laser are polished steel that is gold plated , if you do try laser something polished that wont absorb the beam , it will scatter it with potential harmful effects if you dont run a closed box. The beam will diverge a lot and pobably wont be that coherent by the time its bounced off so it's most likely not that big a deal inside the box.
We too have lasered many mirrors both sides and never had a problem , as Bruce says , the laser energy is absorbed by the time it has done its work on the glass.
You dont laser stuff like teflon either..be careful of plastics and some synthetic fabrics/foams , some will not respond well and some are toxic.
Of course flamable items are your biggest risk in a laser , far more damage caused by laser fires than most anything else.
We have tried just about anything we can get our hands on in the laser , in terms of plastics , if it smells funny , like acrid and/or discolours , we just pass.

[Joe Pelonio]

Stop by the shop here and I'll show you the etching on the inside of my glass top where the beam bounced off the front of acylic mirror. The idea that the laser "does it's work on the mirror" is only true for me if I apply transfer tape to it. You won't get me to put bare mirror face up in there again. A couple of marks on the glass I can live with, but that beam could just as easily cut through a wire, hose, or belt.

[Dave Jones]

I'll show you the etching on the inside of my glass top....

I'm guessing you meant "acrylic top". UV laser engravers use acrylic lids because glass would pass the UV through.

[Rodne Gold]

I wonder why you are having those issue Joe?
I do a lot of acrylic mirror work front and back engraved , same with glass and in fact the "vinyls" we use as masking for etching and sandblasting are polyester foils (silver and gold) and are highly reflective and we never have a bounce back or internal etching problem?

[Tom Radachi]

Could you put laser beams on a sharks head?

No, only on evil sea bass...:cool:

[Joe Pelonio]

I'm guessing you meant "acrylic top". UV laser engravers use acrylic lids because glass would pass the UV through.
No, Dave, my Epilog has a glass top. Rodne, I have cut through mirror gold and silver poly films on things with no trouble, but always put transfer tape on it.

[Joe Pelonio]

I went ahead and contacted Epilog technical support. They say mirror must be done upside down, or there's a "chance" that it will reflect back and damage the machine. I'd be curious if owners of other makes find that same recommendation from their manufacturers.

[Dave Jones]

This wasn't about mirrors, but about reflections. I saw a post somewhere by somebody using an industrial sized CO2 laser (hundreds of watts) that was cutting metal and said aluminum caused more problems than other metals when cutting since the beam would reflect back up and refocus through the lens, go along the optic path, and go back into the laser source and damage it. I think it was because the molten aluminum was very reflective. He mentioned some special device to reduce the reflection back down the optic path.

[Michael Wells]

I have to weigh in here and side with Joe... I have a 100W Explorer with a nice little black scar on the inside of the acrylic top from a mirror that I surface engraved, back when I was experimenting with my machine.:mad:

[jeremy levine]

This wasn't about mirrors, but about reflections. I saw a post somewhere by somebody using an industrial sized CO2 laser (hundreds of watts) that was cutting metal and said aluminum caused more problems than other metals when cutting since the beam would reflect back up and refocus through the lens, go along the optic path, and go back into the laser source and damage it. I think it was because the molten aluminum was very reflective. He mentioned some special device to reduce the reflection back down the optic path.

Could you mean this
http://www.nilno.com/laser_intro/optics.html
Search the page for "polarizer"

[Joe Pelonio]

I have a new material that you CAN use. I never tried it before today. I needed to make a mounting pattern for a cut acrylic logo to go on a wall and was all out of polytag which I normally use. I looked around and found a roll of Tyvek that I keep for doing cheap short term banners. It's made of pressed very fine, high-density polyethylene so is like heavy paper but
waterproof and tear resistant. It's like they make house wrap, shipping envelopes and painters throw-away coveralls with, but what I get is stiffer and pure white. Anyway it cuts beautifully. Unless you have a vacuum table he pieces like to fly out the exhaust. I used a temporary artist's spray adhesive to stick it onto a sacraficial piece of MDF so it would lay flat and not escape.

[Barbara Buhse]

Joe,
How about a picture of that cut tyvek?

[Joe Pelonio]

Maybe I'll do another sample of it tomorrow. It's going out for installation
in a few minutes and my camera is in my Explorer, which my wife borrowed to take her mother to the eye doctor (87 and can't get in my wife's Liberty, plus not enough room in it for the wheelchair)

[Joe Pelonio]

Here's your pic Barbara. This is a smaller version, the actual installation template was close to 36x36 and I did it in 3 pieces, taped together.

[Dave Jones]

Could you mean this
http://www.nilno.com/laser_intro/optics.html
Search the page for "polarizer"

Jeremy, actually, no, what I saw was a post on a forum somewhere that was talking about cutting different types of metals and the problems with each, with aluminum specifically being mentioned as having a big problem with reflections back through the beam path.

[John Minton]

Hello

Joe is right the beam can bounce back and were it goes and how powerful it is is anybodies guess. With the 35 watt down your risk is lower but wires and hoses could be at risk. Above 35 the risk goes up I just don't have much time with my 35 watt yet to know.

On my metal cutting lasers you better be on your toes. 10 years ago on our 1500 watt machine we were cutting copper the beam reflected off the surface went back up and cooked the focus lens. It was in 3 pcs when I took it out. When we got our 2600 watt machine we ask the service man about copper, he said that if you were not living right the beam could go all the way back into the tubes and due severe damage. On that machine the resornator is $60,000.00 not worth the risk. He also said it may never happen but it could happen 1 minute from now. On the bigger machines they have a power meter which is supposed to see the extra power and shut down but will it do it before damage ?????

Good luck

John

[Joe Pelonio]

Hello

On my metal cutting lasers you better be on your toes. 10 years ago on our 1500 watt machine we were cutting copper the beam reflected off the surface went back up and cooked the focus lens. It was in 3 pcs when I took it out. When we got our 2600 watt machine we ask the service man about copper, he said that if you were not living right the beam could go all the way back into the tubes and due severe damage.
John
John,

I contacted a local guy to cut something for me that was too big to fit in my 12"x24" laser. It was Romwark Lasermax laminated onto 1/4" black acrylic. He said they couldn't do it, because the Rowmark would melt,
on his machine with 1500 watts. Don't those have a power setting low enough for that? (had to send it to a CNC guy)

[John Minton]

Joe

I believe he is thinking that with the romark on top and enough power to to cut thru 1/4 he will mess up the romark. Can he cut the 2 pcs seperate and you bond them after. Or maybe run with romark down he will have to be very careful about flashback damage on the romark. Most people with high power lasers have not had much practice with turning their machines down low. Hope this helps If I can be of anymore help just let me know.

John

[Joe Pelonio]

Thanks, I was just curious. He said they mostly cut metal and thicker acrylic. I got really good results with the CNC, the edges are just not as nice.

[Meagan Britz]

Yes, it burns beautifully!

[Frederick Skelly]

Yes, it burns beautifully!

I noticed this thread is 14 years old.