Tips for Lasering Granite tiles with Photos

[Michael Headrick]

Hello, I'm just learning to use my laser and could use some wisdom on some questions and problems. I have an epilogue mini 35W, and absolutely love it when I'm working with anodized metal - flashlights, water bottles, etc. I'm having a lot... LOT... of trouble when I'm working with granite, however. The pictures come out either acceptable or horrible, rarely anything in between. I'd much prefer having them come out good or great ;)

--- First, my material. I've been using granite tiles purchased from Home Depot, Lowe's, etc. I've noticed that there has been inconsistencies in batches - sometimes the finished product is much lighter or darker, sometimes I have unexplained dots that didn't get etched into the picture. I'm looking at getting the material from Laserbits instead, but going from $2-4 per tile to about $15 (with shipping) per tile has me really worried. Right now this is my only income, so dollars are being stretched as much as possible till I can get this business self sufficient. Is the quality of their material worth paying five times the cost? If not, are there other suppliers that offer quality product with competitive pricing? I have no problem paying for quality... as long as I GET the quality I pay for. I live in Southern California but don't have a preference between a local vs an internet supplier.

--- Second, my settings are very different from what I've read other people using and suggesting. In Epilog's owner's manual, as well as the Laserbits site, the recommended Speed/Power settings are 100/25 for marble/granite. When I set my laser to that, the tile barely has anything cut into the surface. Until I raise it up to around 100/60 or so, I cannot have the entire picture cut into the tile - parts just don't show up. Unfortunately, if I raise it just a little beyond that threshold, I lose a tremendous amount of detail. Anything in light shades is bleached out and blended together so that the tile is basically trashed. Lettering and solid designs/clip art are not a problem, it's strictly detailed photos that aren't turning out. I'm cutting at 600 dpi. Would this likely be a problem with my laser, shoddy materials, or does the problem exist between the keyboard and the chair?

Any help would be greatly appreciated!

[Rodne Gold]

There is only so much resolution a tile can hold , the laser spot size is the key to this , a 2" lens cannot actually resolve above 300dpi , ie it can only engrave at 300 dots per inch if you want to see "dots" as its spot siz is 1/300th of an inch. If you overlap dots , you will lose detail , but you would also get "deeper" engraving.
One has to remember that a stone tile is not a photograph , its a tile and thus you can get away with lower resolution , the fact that you can get a recognisable image on a granite tile is pretty good in itself.
The problem when "overpowering" a tile is that you get dot gain , much like dropping too big a drop of ink on paper and it "spreading" out.
If you want to actually ETCH tiles deeply , sandcarving would be better , but your resolution would drop a lot.
GIGO applys here too , garbage in , garbage out , not every picture will be capable of displaying the best results and the prep of the picture is also important.
The Blacker and the more consistent the quality of the material , the better results you have , however at $2 vs $15 , you might just have to settle for some variabilty in quality to achieve a sales price point.
IMO there are better ways of making money than doing onesies on tiles , the prep work , dealing with customer , variabilty of tile , variability of results cannot make this profitable unless you have a fully sorted (read real quick) workflow setup. I actually think that using a laser for onesies and small engraving jobs is a loss making proposition when every expense is accounted for , especially time. If you could charge outrageous usurios prices for a job , like $150 for an a4 tile or something like that , it may be worthwhile , if not , in all probabilities setting up a barrow and selling apples and bananas on the street would make more for less effort :)

[Tim Bateson]

You may also want to go to Home Depot or Lowes and buy black tile for just a few bucks each. If you are are careful, you can get some real nice tile & for only a few dollars. Experiment on these. Actually you may find some of these of high enough quality to sell.

[Dee Gallo]

Hi Michael, welcome to the Creek!

I have used black granite tiles from Home Depot with good results. I used settings of 100 sp/56 power for photo montages at 300 dpi. What is the wattage on your laser? Mine was 35 w. I suspect the problem is in the way you prepared the photo since you are getting good results on text and clipart. That is a skill unto itself and you can do a search to find lots of advice about the subject, which would be well worth your while.

cheers, dee

[Ron Chapellaz]

Micheal,
Here is an answer that I posted before...
I too had problems with a mottled grey look when I did a project that involved 3 tiles. One tile turned out speckled and the other 2 weren't. It is not easy to tell when a tile will laser nicely or not just by looking at it. What I found to be important is to look at the back side of the tiles. It seemed that the tiles that turn out speckled looking had a grey back whereas the ones that weren't speckled had a slight brownish tone to them. It is hard to tell the difference so when I buy tile I bring in a sample so I can compare and make sure I come home with the better ones. I did find that the two tones of granite are mixed in the packages themselves and that there are more grey backed ones compared to the brown. The last time I went and bought some, I dug through and pulled out only 6 tiles out of over 20, due to color and busted or scratched tiles.
I found this video on youtube from Mike Clarke on granite http://www.youtube.com/watch?v=ZubRDUrg_7k (http://www.youtube.com/watch?v=ZubRDUrg_7k)
For my Epilog 35 Watt I used 60 speed 30 power 250 DPI with Stucki.

[Martin Boekers]

Granite is difficult at best black marble is much better, but won't hold up in outdoor use.

As Mike started in a new thread search YouTube there are many wonderful videos there.
You may want to set up a book mark folder for easy access when you need to refer back.

here is a great one from Roy Brewer on prepping an image for engraving, quick and simply
explained. Plus you have all the software needed with Corel.

www.youtube.com/watch?v=yllZTBA0HO0 (http://www.youtube.com/watch?v=yllZTBA0HO0)

[Bill Cunningham]

I did a few jobs using the H.D. granite, but nothing I would have sold because I like polished edges.. The lasersketch granite (they call it marble) is much better. The result you get in a granite photograph, are based mostly in the photoprep before you etch the stone. This is something that really can't be taught, you have to train your own eye, and use what pleases you.. Once the photo prep is done, sized etc. I usually use the generic black granite setting in photograv. for the final dither,and reversal to negative for etching.

[Dan Hintz]

I did a few jobs using the H.D. granite, but nothing I would have sold because I like polished edges.
Bill,

I actually prefer the contrast of the dull edge... in fact, I'll usually take a ROS with 120 or 180 grit to the edges and give them a 45 degree bevel. I may not be able to make the edges shiny, but I make it work for me, not against.

[Michael Headrick]

Thank you guys very much for the tips and videos! I'll be putting them to use tonight, hopefully I'll be seeing some improvement - I'm sure everyone here has felt this frustration before hehe

Dee - my laser is also a 35W, so I'll start off by trying both the settings you and Ron have posted. Turning DOWN the resolution wasn't something that had actually occurred to me. It makes sense that the laser will only be able to do a certain level effectively, but I had assumed that that level would have been 1200 DPI, since that's what the driver's max setting is. Going to a lower resolution will also speed the job up some, right? Since it will only have to make half the passes on the tile?

Those video's were both great, especially since they were both using software that I already have. I'd prefer seeing their actual end product, though, so if anyone else makes one... ;) I have both CorelX5 and Photograv, but haven't seen much difference in the end result using either. From reading here I know there are two camps, so I figure whichever ends up being the better combination of quality end product and ease/speed of use will be the one I stick with!

So the laserbits product has polished edges? That's something I think I would like a lot... more of a display piece instead of a construction material look. I have been using titanium white artist's oil on my tiles when finished, and make sure that I use it on the outside edges as well. It gives it a cleaner look, like I MEANT to have those edges not be polished. Beveling the edge is a really good idea. What does ROS mean, though?

You guys are great, I'm certainly glad I found this community!

[Ron Chapellaz]

I PM'd you Michael.

[Dan Hintz]

Turning DOWN the resolution wasn't something that had actually occurred to me. It makes sense that the laser will only be able to do a certain level effectively, but I had assumed that that level would have been 1200 DPI, since that's what the driver's max setting is.
It's not an issue with the laser not being able to reach that resolution (there's a caveat to that, mind you), it's more an issue with the substrate not being able to handle it. A quality piece of anodized aluminum is about the highest resolution medium you can work with... marble is on the lower end of the scale, right above granite and wood.

[Mike Null]

Dan

I would take issue with a blanket statement about marble. While I don't use a lot I have had some very good results with marble. That said, there seems to be varying grades and i don't really know how to select it other than picking a piece I like or buying from an importer who seems to have good stuff (built into plaques).

[Dan Hintz]

I agree, there are certainly varying degrees of quality for marble (veining, etc.), but overall you won't get much more than 300dpi out of even good marble. A quality piece of granite (i.e., extremely low flecking, like what LaserBits sells) is close to a 300dpi substrate... lower quality (Home Depot) is probably more a 250dpi substrate, along with most tight-grained woods. A loose-grained wood is probably 200-dpi and below...

[Bill Cunningham]

I agree, there are certainly varying degrees of quality for marble (veining, etc.), but overall you won't get much more than 300dpi out of even good marble. A quality piece of granite (i.e., extremely low flecking, like what LaserBits sells) is close to a 300dpi substrate... lower quality (Home Depot) is probably more a 250dpi substrate, along with most tight-grained woods. A loose-grained wood is probably 200-dpi and below...

The next time your in HD Dan, pick up a 12x12 of their Empidor brown marble.. Set up a gray scale photo file about 2 x 3" and etch it using only the grey scale driver, at 300, 600 and 1200 dpi (or universal dpi's of 200,400,800) at low speed/ high power ( I use 100p & 45-50 speed on a 35-40watt machine, so what ever the equiv. is on yours).. You will see a big difference between all the samples.. Use the same speed power for all. (real marble is very forgiving, you can even go over it twice to make it whiter) The 1200 dpi will be equiv. to a good clear b/w photo.. The others will be acceptable and the difference noticeable.

[Craig Matheny]

I did a few jobs using the H.D. granite, but nothing I would have sold because I like polished edges.. I use this or items from a local marble granite store after I cut my pieces to size I use my fine grinding wheel on my table top grinder to put the slight 45 back on the 4 sides and then take polishing compond for stone and put it on other side of the grinder that has the polishing wheel and in 2 minutes I have re set the angle and have a mirror finish on the sides and money left over for lunch and I can make any size I need and not pay top dollar. Give it you will be shocked how easy it is I did this by accident and now it is the norm.

[jerry platter]

How can I cut shapes out of marble or granite tile. Or is there a place to buy custom or stock shapes in these materials for laser etching and sandblasting?

[Dan Hintz]

You're not going to cut it with the laser, if that's what you're asking...

Some places (like TimberBits) sell a couple of shapes (round, heart, etc.), but anything truly custom is better done by you if it's in small quantities. You can use a wet tile saw for simple, straight cuts, or search for a ring saw to do complicated scrollwork. Smoothing the cut edge can be done pretty quickly with a sander, but polishing the edge will require some time.