Concrete pavers

[Jeff Chumbley]

Hello, I tried to do a search in this forum for concrete pavers and came up with nothing. I have a customer that wants 500 concrete pavers engraved with donor names. Has anyone had any experience with this. I am thinking either an epoxy fill of some sort or they have the painted pavers with the concrete color as the contrast.


TYIA

Jeff

[Jerry Allen]

I've done a couple of pieces of flagstone. You can't cut very deep unless you sand blast it. I don't know how these would hold up to being walked on a lot. I assume concrete would be similar or harder to engrave with a laser.

[Jeff Chumbley]

Were those just engraved or blasted. They look very nice. I assume :eek: that you used a mask.


What settings did you use? I have a 45 watt epilog 24tt



Jeff

[Thomas Hempleman]

Jeff,

I have lasered a few concrete paver bricks and they look nice but take a lot of laser time. My 30 watt machine was set at 100% power and 5% speed. Even then, the brick was not etched very deep. I used a mask (I've found plain old Scotch packing tape works fairly well) and then paint filled the etched area. I'm still experimenting with paint types that will hold up to outdoor weather, sun and foot traffic. Nothing seems to hold up real well, probably because the etched area isn't very deep.

Tom

[Jerry Allen]

Yes, lasered.
The surface is very rough and grained and I didn't use a mask.
I used 50% speed and 100% power on a 25W machine. I haven't played with it enough to get an optimized number. One of them I burned twice, but it made no difference, similar to doing glass or granite in that it just breaks the surface and goes no deeper.

[Rick Maitland]

Thomas run a search on Lithochrome paints. This type of paint is used on headstones and works very well. I order my paints from www.granitecitytool.com (http://www.granitecitytool.com) .

[Jeff Chumbley]

Jerry,


So the photo shows the engraving as white. Did u color fill that or is that the result of the lasering? If it is colored how did you do that without a mask. I would think that flagstone being porous would leech away wherever it may.


Jeff

[Jerry Allen]

Not colored, that's just the lasering.

I found this article today about brick:

ENGRAVING ON BRICKS WITH GCC LASERS


Model: Mercury L30 Watt or L50 Watt



Suggestions:



The slower and/or more power you put to it on the first pass, the more of the white residue is produced. This residue doesn't just brush away, at least not completely. A cleanup pass seems to work best. A paper mask doesn't do much since the residue is primarily left inside the letters. Air assist was used. A 50 watt machine is my recommendation, but a 30 watt will do if time is not critical.

The darkest contrast or "glaze" is produced with lots of power (or slow speed) on the first pass. Perhaps due to the more raw material the laser interacts with on the first pass. So the process of high power / low speed on the first pass, and a second pass to clean up the residue seemed to produce the best results (see photos).

#1 100p/5s (38 min)

#2 100p/50s (3 min)

Running at 100p/8s on the first pass reduced the amount residue substantially, and decreased engrave time to 21 min, but the contrast suffers. Thess samples were done with a red clay pavers (no holes) brick from Home Depot. They are available in a half thickness which is more acceptable for mailing but still weighs in at over 3.5lbs.

I stumbled across some italian clay tile at Home Depot that has an unglazed surface, and engraves beautifully in one pass, at 100p/15s (8:34). It is also much easier to mail as a sample, and while not a true replacement for a brick sample, it gets the point across.

[Thomas Hempleman]

Thanks, Rick! I'll give them a try.