Engraving Granite?

[Cold Fusion]

Anyone have any advice for engraving letters in Granite?

[2muchstuff]

Well I can say this, the people who do mounuments (headstones), they sand blast the letters. They use duct tape as a mask for the letters.

[Hack]

I haven't fabbed much granite, but have "been around it" so to speak. I am under the impression that you can route the stuff with diamond tipped router bits. Same type of stuff that you would manufacture other stone and concrete products.

Grinding wheels are quite easy to find at the big box stores, but not router bits. A quick google search will give you some sources I'm sure.

This stuff is very dusty. Use eye protection. Some water is very helpfull in keeping the dust down and prolonging th life or your tooling.

As peviously mentioned, Sandblasting is the preferred method. Also, you can use a CO2 laser,

[debogus]

Duct tape ?

Mask from Hartco is good stuff . I use a vinyl plotter to cut it . 35mil for granite ,will take alot of air without a problem .
Perhaps you could cut the mask on the stone with a router then blast it .
Havent tried that yet , but need to try it for more detail ,weeding small stuff is a pain.



What are you making ?

Dave

[tension]

Engraving granite on a CNC is scary if you ask me. Granite is a hard substance and I've had my fair share of tool ware and tear. First time I used my engraving tool I had to make a spot into absolute black so we could inlay 1"x1" strips of onyx. It obliterated the tool no matter how many passes or how slow i ran it. My suggestion to you if your CNC engraving into granite is to not unless your tool is thick (which ultimately limits your precision on smaller engravings). Marble on the other hand cuts like butta. Theres a picture in the sticky post at the beginning of the "Glass, Plastic and Stone" section of this forum with a picture of an engraving I did into marble.

[awerby]

then that should work okay with a diamond drag tool. Usually these are held in spring-loaded holders that pressure it against the work. Just remember not to turn the spindle on...

If you're talking about removing material, though, I wouldn't do that to a Bridgeport. The grit will get everywhere, and will not do your sliding parts a bit of good. You need to use coolant with most diamond tools, but the grit will be taken up in your coolant system and destroy everything it touches. Instead of that, I'd rig up a swivel knife to put in the spindle. Use that to cut the edges of a stencil stuck down to the stone (shelf paper works if this is a one-off) and then use abrasive blasting to actually remove the granite (safely away from the Bridgeport).

Andrew Werby
www.computersculpture.com

[Stepper Monkey]

Originally Posted by awerby You need to use coolant with most diamond tools, but the grit will be taken up in your coolant system and destroy everything it touches. Andrew Werby www.computersculpture.com

Try using an old medical peristaltic pump, the kind used to pump blood in and out of folks. They have no moving parts to get ground up, they are nothing but a seamless loop of plain old flexible fluid hose. They are designed to keep blood from getting contaminated from outside, but this also works for keeping nasty gritty stuff inside without touching anything but the feed hose.
Think of grabbing a hose, pinching it, and running your fingers up it to squeeze out fluid. Now do that alternately hand over hand, timing it in such a way that the fluid flow can't back up each time you release to move one hand or the other.
You can make one with almost any tiny motor, a stick, two plastic sliding closet door or window rollers, and half of an old coffee can in about twenty minutes. Or buy a surplus programmable flow medical unit for usually well under $100 bucks (hospitals don't seem to want old used equipment for life support systems for some strange reason)

[Egar Twins]

Finesse is all it takes....good success can be had in engraving side of the business and I take great pride in the pieces I have produced...pictures to come!

[Making chips]

Engraving granite can be quite a pain. I have used everything from electroplated diamond bits, to carbide. None of them work well. If you were cutting marble, limestone, or soapstone it would be a different story. This is why monument companies sandblast. I have seen some engraving on a waterjet with limited sucess.

Paul

[coltons customs]

Originally Posted by Cold Fusion Anyone have any advice for engraving letters in Granite?

hello I currently own my own buisness doing just that i build everything from small keychains done with 3/4 inch gravel to commercial signs that have ranged in the 20 feet tall by 15 feet wide rocks i mostly do stone but also do glass tile and wood as for granite i will tell you the easiest is with a sandblaster i have done it with a cnc router (not recomended) i spent around 1700 to get mine fixed after doing so and the results werent the greatest as granite has alot of hard spots in it that the roter will hang up on i use a sandblast mask material that i buy from 3 m aprox 12 mil in thickness and cust it with a viny plotter and a 60 degree blade it is self adhesive but does not stick well to raw (unpolished rock) i know of a few tricks to help this but dependes on the surface of your granite weather it is smoothe or round etc email me if needed at coltonscustoms06@msn.com i will be glad to help as for sand it also depends on the size of your rock aluminum oxide cuts the fastest but is also the most expensive if your product is small enough you can use a sandblasting cabinet wich can be picked up at a place such as harbor frieght for pretty resonable if it is too large i would suggest using black magic or black beauty it will use alot of sand so be prepared garnit also works good if you can find it most sign companys will have the sandblast mask material if not any headstone shop uses it if you wish not to try it most headstone shops will engrave it for you ( for a fee of course) you can aslo use a laser but it will only etch the surface like i said feel free to email me i will be glad to help also my website is www.coltonscustoms.com so you can see what can be done with a sandblaster

[coltons customs]

Originally Posted by debogus Duct tape ? Mask from Hartco is good stuff . I use a vinyl plotter to cut it . 35mil for granite ,will take alot of air without a problem . Perhaps you could cut the mask on the stone with a router then blast it . Havent tried that yet , but need to try it for more detail ,weeding small stuff is a pain. What are you making ? Dave

it can be done but it is also a pain and generally ruins the mask although i have used my laser to cut through mask that has been applied to the stone and then i blast it , also just some info 3m just relaeasd a new mask that is a high tack baking it works awesome if you experiance blow off while blasting (but duck tape really is the trick...phht for maski material ive tried it and it lasts about 2 seconds.) i have also cncd lexan to use as a mask on some flat stones the laser will cut way more detailed stuff ont he mask than the router

[laserboy]

you can use laser engraving, just have a dust collector available and then you can do almost any shape without masking.... the fun of lasers! only limited to the size of glavo motors marking field. and power of course.

lase on