Laser Engraveable Items. What the Laser can and cannot do.
Can you engrave on this?
There are a number of things you can use a laser engraver on. I have engraved hardwood, softwood, plywood, glass, seashells, polished stone, and have been asked if you could engrave on a number of other things. The problem comes when that material contains chlorine. Chlorine is dangerous, poisonous, and will cloud the optics of a laser system. My laser has a stipulation in the warranty that I do not try to laser engrave anything containing chlorine, or my warranty is null and void. Such things include Polyvinyl Chloride, and table salt, which I definitely remember being asked to engrave. Sorry. No can do.
Metal can only be safely and effectively engraved if it is coated with a laser sensitive material, or it will just work like a mirror, and send the beam off somewhere else, which could be dangerous. Especially coated metal surfaces, or the material to create such things, can be found at www.laserbits.com
Stone can be successfully engraved if it doesn't contain any chlorine, which can be in metallic salts. I would suggest researching each kind of stone before the engraving is done. I have engraved on jasper, which is a non-patterned variety of Agate, and it works well. I found it works best if the polished stone is dark and opaque, such as dark Jade, obsidian, or marble. Look in the Audubon Mineral book I mentioned before to see if the rock you were thinking of engraving has Cl. Granite, with all its different ingredients in small bits could be engraved, but the image was hard to see for all the black, white and red spots.
Yes! You may engrave on wood. It is a great material for laser engraving. The only problem is that if you are engraving on thin pieces, and intend to cut out irregular shapes, the rules for cutting items with a scrollsaw will apply to a laser. Small pieces with grain lines running across the short direction can break if it is regular wood. I prefer working with thin pieces of hardwood-plywood, as it usually has reinforcement under those places that would otherwise break from stress. In picture two I finished a sheet of towers for a castle made of 1/8 inch (3mm) plywood.
Another problem you may see in working with wood is in softwood, the heat of the laser can drive sap out of the wood, and if the laser hits it, it can catch fire. At that point, you should stop everything, and grab the CO2 fire extinguisher, and hope that turning off the forced air stops the flames. I have worked with sappy pine, but I much prefer clear, knot free, hardwood-plywood. Globs of sap can be cleaned away with turpentine, providing you let it completely dry before continuing to laser. Also, avoid going through knots in softwood. The sap concentrates there.
I have worked a little in seashell. It tends to smell strange, but you can get distinguishable images in it. I would make sure that there is no salt in it before I did a job on it. sticking with the near flat clamshells would work best for that, because you can get a clear separation of the shell and the shellfish's mortal remains.
Glass will laser engrave much like stone, even mirrors can be lasered, although you can't cut it with the conventional Epilog laser. I would make sure that the vacuum was attached and running at the time to prevent glass dust from accumulating on the artwork.
Leather will work, but it can smell awful, like something is burning alive, because, well, it once was alive, but you knew that. The smoke from burning leather is no more toxic than any other smoke, and as long as you keep the fans running as you work, the smell won't be too bad.
Synthetic rubber can be lasered, but it is going to smell extremely bad, just as I said about leather. I suppose if you want to make a rubber stamp, you can, but I haven't actually tried this.
Plastic can be laser engraved, but only types of plastic that don't contain chlorine. Polyvinyl chloride, or PVC, obviously contains chlorine. An example of Chlorine free plastic is lucite. Once again, the www.laserbits.com website is very helpful in suggesting useable materials. I recently made a stencil from Lexan, using the laser to shape and cut the parts, and although the plastic stuck in the cutouts, it could be forced out with a pocketknife. The edges where the laser had cut through were somewhat brown and rough, but the whole thing made a good drafting tool for laying out a basic heraldic coat of arms. See picture number one.
Whatever this stuff is
I'd err on the side of caution. If you don't know what precisely the material is, I wouldn't try engraving on it. You only have one warranty, and you don't want to lose it.
Good Reference Books to have
This book talks about specific minerals, and gives their chemical content so you can avoid lasering the wrong materials and hurting your laser.