Full Version: Newbie having dificulties engraving glass
From: nicho (ROYNICH) [#1]
2 Mar 2007
To: ALL
I'm new at this and have been trying to engrave some wedding toasting glasses for a friends son's wedding.
The crystal glasses cracked at high power and didn't engrave fully at 80%.
The cheaper champagne flutes engraved but on the scale of 1 to 1.
1 good one for 1 failure. There's something I'm not doing right.
The laser froze 4 times in the afternoon. My tech tries to tell me it could be a spike, but 4 times in such a short period of time. There is anti-spiking installed on this powerline.
Any advice would help.
Regards
Nicho
From: Mike (MIKEN) [#2]
2 Mar 2007
To: nicho (ROYNICH) [#1] 2 Mar 2007
From: nicho (ROYNICH) [#3]
2 Mar 2007
To: Mike (MIKEN) [#2] 2 Mar 2007
I've very recently bought a Gravograph LS100 which is a 30 watt machine. I'm based in South East Queensland not too far from Brisbane.
I have been engraving pens for a few years now with both hand pantograph and a rotary engraver and am hoping to be able to learn how top use the laser.
I'm not having too many problems with lasering pens but have to learn everything else.
Regards
Nicho
From: Mike (MIKEN) [#4]
2 Mar 2007
To: nicho (ROYNICH) [#3] 3 Mar 2007
I believe your machine is made by Universal Laser, jsut as a point of information.
I suggest that you go to the Epilog site and look over all the things they offer in the way of tips and tutorials. http://www.epiloglaser.com/tech_library.htm
I just finished a glass job engraving the Boy Scout logo on about 30 pieces. I used a lower power setting and lasered in 2 passes.
I used 800 ppi about 50 power and 40 speed and 500 dpi. I have attempted to adjust my settings to what I think you would use.
When doing round objects (wine glasses) focus is all important and if you do not have the rotary device your engraving area is extremely limited.
Most laser people have had bad experiences with crystal due to the density and lead content. Over heating causes the crystal to fracture and this happens rather easily. Sandblasting is superior.
Some people make it a practice to put wet newspapers on the glass before engraving; others like to use water and dish detergent. I've tried both and didn't see the benefit. I would try both these methods as many people with more experience than I believe they work.
Good luck and welcome to the forum.
Message 6226.5 was deleted
From: Precision Laser Creations (PIZZAMAN) [#6]
2 Mar 2007
To: nicho (ROYNICH) [#1] 3 Mar 2007
Nicho,
You might have better success with the cracking if you lower your dpi to around 400. I've had that problem in the past especially when engraving a grapic that has a dense area. The laser stays in one area too long and the heat cracks the glass.
Tony
From: ray (RMV0215) [#7]
2 Mar 2007
To: ALL
I've not tired crystal, however on glass and mirrors I use a dark brown for color instead of black. It gives it a nice frosted look and actually lowers the power. I normally run the glass at 40% speed and 100% power on a 40 watt Epilog.
Ray
From: JHayes55 [#8]
2 Mar 2007
To: nicho (ROYNICH) [#3] 3 Mar 2007
Mike has given you some excellent info. To add to what he had to say - laser is not well suited for crystal. Inexpensive Glass does fine - we engrave at high power setting and high speed and it works well. All glass is not created equal so you will need to experiment. We have a 75 watt and use a setting at 90 power and 100 speed. We normally do not use and water or paper - when we need too we use a little liquid dish soap.
Good luck.
From: nicho (ROYNICH) [#9]
3 Mar 2007
To: ALL
Many thanks for the advice.
My rotary engraving kit is not operational as yet as it came without the holding clamp. So I have been trying to do the engraving in a jig. On the cheaper glass it works quite well but on the crystal the name which is a bold text at 6mm cracks the glass at 95 power. The rest of the text is clear. At 80 power the bold text name is fine but I loose the occasional letter in a scripture verse that is beneath it. I'm getting a clamp for the rotary fitting tomorrow or Tuesday.
I'm just going to have to apologise on this one, but I have done some cheaper champagne flutes for them. :-$
It was a very fine or thin crystal as well...thicker crystal may have been more forgiving.
Regards
Roy N.
From: gravoman [#10]
4 Mar 2007
To: Mike (MIKEN) [#4] 4 Mar 2007
Mike,
1. The LS100 laser engraver in proudly made by Gravograph, not ULS, and uses a Synrad laser source.
2. Crystal glass is not well suited for typical laser engraving. That is exactly the reason why crystal is used for 3D laser engraving by using 2 laser beams that create a crack in the glass.
Gravoman
From: Mike (MIKEN) [#11]
4 Mar 2007
To: gravoman [#10] 4 Mar 2007
I did not imply that crystal was good for laser engraving--just the opposite.
From: Bob (ALLSPORT) [#12]
4 Mar 2007
To: ALL
Just a suggestion, but I'd try 300dpi. Less heat is input to the surface and the material won't allow fine detail anyway.
I remember doing a series of crystal glasses several years ago and breathing a sigh of relief when I got them finished. Back at my desk I was wondering what that "tinkling" noise was...Even after at least 5 minutes the glasses were still undergoing heat stress and softly ticking to themselves as they continued to fracture.
Lasering fine crystal is something we no longer offer...
From: Swami [#13]
4 Mar 2007
To: ALL
From: Harvey only (HARVEY-ONLY) [#14]
5 Mar 2007
To: Swami [#13] 5 Mar 2007
From: Doc (GREAT_ATLANTIC) [#15]
5 Mar 2007
To: Swami [#13] 5 Mar 2007
The upside if done correctly is a good, clean frosted etch that's considerably more affordable than sandcarving. The downside is that leaded crystal takes much more care, and frankly doesn't mark as well. Optical crystal is fine.
We did 500 beer mugs for a police Christmas party this season that would have been out of the question price-wise had they been sandcarved. Since the mugs we used were inexpensive glass, the laser did a great job on both text and the engraved badge. All they required was a quick rinse with a ScotchBrite pad.
EDITED: 5 Mar 2007 by GREAT_ATLANTIC
From: gingem [#16]
5 Mar 2007
To: Doc (GREAT_ATLANTIC) [#15] 5 Mar 2007
Hi Doc
I know most of you do glass with a laser, but I have a question pertaining to you saying the cost for sandcarving would be greater than the laser. On a typical 15oz mug or glass on one side I usually do an area of about 3x4". My cost for the mask is $0.60 and time wise it takes about 3-4 minutes to tape and blast the glass. On my engraving machine I figure time to be between $50.00-75.00 an hour but you can only do one mug at a time while I can do many. How much time and cost is it for you to use the laser?
From: JHayes55 [#17]
5 Mar 2007
To: gingem [#16] 5 Mar 2007
Bill - I am not trying to disagree here - I do believe sandblasting looks better than laser engraving on glass (deeper cut gives it a better look).
You said it is only .60 for mask and 3 to 4 minutes masking and blasting - but how about preparing the layout, processing the mask - (photo, laser or cut vinyl mask) and then there is clean up of the finished product - wouldn't those processes need to be included into the cost?
The glass I get asked to do the most is glasses with names on them - 6 for the bridesmaids and 6 for the groomsmen. Each with a different name - so then to sandblast I would have 12 masks to make. With the laser it is quick to do 12 names - I layout my piece size Corel, place a box where I want my text, type the names over to the side and then move one name over to the box center, as that name engraves, I move it out & move the next name to the box center - an so it goes till I am done with my list. As an example what would you charge to do a dozen beer mugs each with a different name?
I am asking all this for knowledge. We are considering adding a sandblast unit sometime this year since no one in a 60 mile radius of us advertises they have one.
EDITED: 5 Mar 2007 by JHAYES55
From: Dee (DEENA-ONLY) [#18]
5 Mar 2007
To: JHayes55 [#17] 5 Mar 2007
Joe,
I'll throw our rotary pricing into the mix. If they are the customer's glass and all the same we would charge $15.00 to do the first glass with 1 name and $4.00 for each succeeding mug. If there are 2 different types of customer's glasses (mugs for the guys, flutes for the girls) the first 1 of each type would be $15.00 & each succeeding glass of the same type would be $4.00.
Dee
PS We can do crystal! (devil)
EDITED: 5 Mar 2007 by DEENA-ONLY
From: gingem [#19]
5 Mar 2007
To: JHayes55 [#17] 5 Mar 2007
Hi Joe
I think the problem most people have with sandblasting is that they don't do it so they think the time involved is a lot more than it really is. Here is the exact steps that I take and I will use your example of the 12 mugs:
Using your graphics program, I use Corel, create your artwork for a mug with the name in it's proper place.
copy that artwork and change the name to the next. In my example I made the artwork 3x4" so I can easily but 6-9 on a sheet on of 8.5x11. I print this artwork on my master and develop one sheet of film, time 45 seconds.
I wash the film, 1-2 minutes, (remember this is at least 6 mugs) let it dry while we do the next. Sheet which was developing while we were washing.
Cut the masks apart and stick them on the mugs. Tape around the mask, we use plastic garbage bags and very little tape.
Blast the piece, pull of the bag and there is no clean up except to wipe it when you wrap it and put it in the box.
We are doing a 300 piece mug order for our local PBA and from start to finish, while we still were working on other jobs the entire job too 1 week with only 2 people involved.
Most people are afraid of sandblasting because they haven't done it. A complete good sandblasting outfit costs less than $5,000.00 compared to any other equipment in our field it is very cheap. The big thing about it it is a service that most don't offer and gets you in many other doors! All types of engraving has it's purpose and each is better at something than the next. But if you can offer all of them it makes you the one source for all of a persons engraving needs.
I will eventually buy a laser, mostly for wood and material like that. I still haven't seen a need for it yet to think about the cost involved. Right now we have equipment from hand engraving through 3D CAD milling equipment, which is really great.
From: Mike (MIKEN) [#20]
5 Mar 2007
To: JHayes55 [#19] 5 Mar 2007
When I was working for the Award Assoc. member here in St. Louis we did literally thousands of glass awards most of which were sandblasted. Our process was to apply a vinyl mask, laser the image in a vinyl mask, wrap it and send down for sandblasting. It would be blasted, unwrapped, glued if necessary, washed and polished.
Low end awards were lasered if possible. Glasses were sandblasted.
When I started my own business I bought the sandblasting equipment and after about three years sold it being totally disgusted with the low income, dirt and high labor content relative to income.
There is no question that sandblasting produces a superior image on glass and crystal but in my situation I just couldn't get paid for it--not to mention I didn't like doing it.
One more point which will probably raise some argument--I felt that the number of mistakes or rejects was much higher with sandblasting than with other processes.
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