PDA

View Full Version : Colorfill Granite/Marble



Sylvia Mossbrucker
06-12-2008, 1:43 PM
Hey everyone, i posted a bit ago with a question on color fill for marble and granite...got some awesome answers and tried them, however im confused???? I used the paint and wd40 method with squeegie and all it did was take all my paint off when I used the squeegie it took it out of the engraved section and off the non engraved section. So I went back to using Rub _n_ buff and it works great for fill but its a huge pain to get off the marble or granite after application anyone have any suggestions??

AND!! when engraving marble and granite (Oregon Seal) I use the exact same settings 100 power/60 speed/1000dpi and black and white for engraving field it works great for marble comes out white and with very acceptable clean lines, however the granite is very thick lined so when I fill it with the gold I loose so much detail? could anyone suggest any different settings or is it just the difference between granite and marble??

Thanks for all your time!!

Jack Harper
06-12-2008, 2:10 PM
Your dpi is huge! I use 200 dpi for marble and 150-175 dpi for granite. This is based on a 1.5" lens and photograv for file prep. I suspect that you are over burning the stone creating a very rough pattern that will catch a lot of color fill causing your loss of clarity. There is some basic science to stone laser resolution. When you fire the laser at a certain speed and power, it creates a dot of a certain size. This is the same principle as an ink printer. If you dots overlap you will get a muddy image. If you dots are too far apart you will lose detail. The best method is to use a gray scale test pattern on the material several times calibrating the laser for the best image over all gray levels. If you search the forum, I believe you will see some of these patterns posted. By the way you need to do this for not only for each type of material but also for each batch as stone varies over time based on what part of the mountain it came from. Good luck.

Darren Null
06-12-2008, 3:04 PM
I used the paint and wd40 method with squeegie and all it did was take all my paint off
The only thing I can suggest here is that you weren't lasering hard enough. To get decent results with colourfill I had to NUKE the marble (100%p 4%s on a 10W laser) to get the holes deep enough for the paint to settle in. If the holes aren't deep enough, the flexible edge of the squeegee will just scoop out the paint, so that's probably your problem. In theory you can use shallow holes, but you'd need a perfectly straight edge that doesn't deform (and yet doesn't scratch the marble). I've not found anything suitable yet.

Agree with the dpi- not so bad when you're doing vector as you're overburning bits you've already done, but a definite no no if you're doing raster. I do 300dpi and that doesn't come out too bad with a 2" lens.

You don't say what power laser you're using, but it looks like you're going too fast. That speed is fine if you're just removing the polish and leaving it with white laser marks, but if you're colour filling you need to go a bit deeper so the fill has something to key to. Granite is harder than marble, so add -say- 10-20% nukage to your settings.

Dee Gallo
06-12-2008, 3:39 PM
I used the paint and wd40 method with squeegie and all it did was take all my paint off when I used the squeegie it took it out of the engraved section and off the non engraved section.

When you use the squeegee, are you using it at an extreme angle or laying it flat down? If the angle is not just about a right angle (just the corner touching the surface) you will create suction and pull everything out. You just want to skim the surface. And using a diagonal stroke so you're not following the lines will help a lot too. The oil will keep everything slippery (not stick to the surface) so the less you contact it, the better and the weight of the paint should keep it in the grooves. You should not have to press hard.

Daniel Cline
06-12-2008, 4:43 PM
Hi Sylvia,

I would only add that granite requires less power than marble and as Jack said they vary quite a bit. I also use much lower dpi - 300 being maximum.
Witk lots of power you can actually carve marble...here is a sample.

David Brasfield
06-12-2008, 5:25 PM
Hi Sylvia,

I would only add that granite requires less power than marble and as Jack said they vary quite a bit. I also use much lower dpi - 300 being maximum.
Witk lots of power you can actually carve marble...here is a sample.

That's very nice work. Do you mind sharing your settings?

Thanks,
David

Daniel Cline
06-12-2008, 6:46 PM
Hi David,

I don't mind sharing but my setting won't mean alot as it depends on the marbleand everyones machines are different. Basically this can be done either as a raster or as a vector fill. Lots of power, slow speed and possibly multiple passes depending on the power of you machine but with 120w you should have no trouble. It is hard to carve small letters because of the heat produced around the interior details, say the middle of an A explodes the stone. Many passes with less power may help with this. It is a bit of trial and error.

David Brasfield
06-13-2008, 9:34 AM
Thank you very much for the information, Daniel.

I think my first try will be to do a vector outline, then a raster fill for some depth. I'll start at maybe 50% power and a higher frequency since I want a sharp edge, and experiment from there.

Oh, and do you do any special masking? Paper and water?

Thanks again,
David