I thought ‘on first sight’ that the rose had a very particular look about it, desaturated color, very vintage. Perhaps that look would be very suited to a certain style & setting.
Notice taken concerning the safety aspect!
If the slight de-focus were used would that cause blurr near borders and would multiple passes change the outcome.
Multiple passes will not work. What does work is one pass, then apply another layer of Copper Oxide, then another pass. The same with the glazes - the second thin coat fills in the brush marks. The thickness of the coating makes a difference and the engraving parameters as well. Spraying the Copper Oxide, for some reason (maybe because the coat is to thin) doesn’t work well at all - a soft bristle brush works best with well mixed solution - the copper oxide settles out VERY fast. Depending on the engraving parameters, you can get what looks like a pure copper finish - very metallic.
I haven’t tried defocusing.
I’ve only tried Chromium Oxide Green once, and I think you can get a metallic silver color with a little tweaking of the engraving parameters.
I’m still looking for a good red that isn’t horrifically toxic. All the potential reds I’ve found contain Cadmium which is so toxic it scares me and I won’t even try it.
The only thing I’ve got a really good handle on is the Cobalt Oxide. I get a good, even dark blue on glass and tile every time. Right now I’m making some shot glasses with blue engraving.
Maybe a little school glue in the mix would help keep it suspended.
I hate to be a nanny, but please realize that heavy metals (chromium, copper, cobalt, etc.) can be extremely toxic. Think of Flint, MI and lead.
With no ability to monitor how much, if any, of the heavy metals is getting into the air when the laser passes over your mixtures, you’ll never know how much you are breathing in until the toxicity shows itself.
If you’re going to try this, please make sure that you are exhausting your fumes to the outside and wearing a mask with the appropriate ratings for these toxins.
School glue is in the mix. The particles are just too big to stay suspended very long. It’s not a problem with a brush. Maybe more school glue would help. The mix I’m using is 1 part school glue and 3 parts water.
I’m aware of the toxicity. Some metals are more toxic than others. I won’t have anything to do with cadmium compounds. Copper and cobalt are not too bad - but I exhaust any fumes outside.
Just about anything you hit with a laser produces some pretty nasty fumes - plastics are particularly nasty - so an outside exhaust is necessary for everything.
Glad to hear that you’ve got a good exhaus system.
FYI, according to NIOSH, the exposure limit for Cobalt is higher than Chrome (VI) or Cadmium. It’s the same as lead.
I see your reason for the good red now! If your getting copper of good appearance then the good red would nail it…with silver too if its doable.
The blue sounds high potential as well, I wonder can you vary the shades.
Let us know if you try the oxides with a bit of glue to delay the settling.
Thanks for the reminder Jim! If its landscaping or coffee…Im a different fella, but the rules here are new and its good to get the odd tap on the shoulder.
I was looking around for IR1064 info and came across an article about color on steel. Maybe you have this info already but just in case I made some notes.
They are for 301 steel but may relate in some way!?
The thing that got me thinking was the shades esp Red, it was the same as yours. The guy said he has not achieved a Rich Red or Green yet…with any test yet, but still searching and Blues were best!.
Inorganic binders work best. Talk, liquid glass? (school glue is organic AFAIK)…
SAFETY FIRST! He stressed.
Just remembered where I saw it…Snapmaker site, Search ‘painted tiles’ I did save the page and have if you need it…I didnt have time to read the tiles article but the metal one had loads of settings info…Maybe for tiles as well.
Notes:-
Dither for richest colour.
Frosted steel (maybe ceramic equivalent of that?).
Dot filled better color than Rasta.
Low thermal conductivity.
Constant power setting.
Overscanning 10%-50%.
Speed 2500mm/min.
13.5% power.
Line interval 0.05mm.
The colors on steel are due to an oxide layer being formed. Colors on tile and glass are are due to the oxides melting into the glass or glass on the tile and changing composition - the copper oxide appears to be pretty much copper dissolved in glass when hit with a laser. When heated, copper oxide really wants to give its oxygen to somebody. Copper oxide and aluminum, for example, reacts extremely violently with aluminum,yielding molten copper and aluminum oxide. I assume something similar is happening with tile and glass - the oxygen is given to the glaze or glass. I don’t know exactly what is going on with the cobalt, or titanium, but I assume some new compound is formed in a reaction with the glaze or glass. From the looks of it, the chrome seems to have a reaction similar to copper, with the result looking metallic.
Can you clarify how this works, or how you set it up to perform this?
Hi Jack
SM Academy (color marking on ss , using SM40w module part 1).
Filling area with color (Rastered lines v dot filling).
(edited by me) From the article:-
" I found that difference in angular color appearance, pronounced…comparing…“Rastered lines” for filling areas as apposed to lubans option for “dot filling”…suspect from difference of roughness of buried metal surface…“I found colors from dot filling…much more consistant viewed from different angles…encourage to try both & see…”.
My statement should have read “Dot filled better color consistancy…”.
How to set that up…I have no idea…yet, hardware sorted, working setup next with diy enclosure & seperate power for lights/fans/exhaust…and then software & settings.
The how it works bit seems to be (after one read & no notes) the MOPA ns-pulse causes a ripple effect on the surface, changing Oxidation layers and reflected color. Also various pigment…thats probably why pigments are used on ceramic…Also color by laser is the most environmentally friendly way of treating metal.
Fiber seems to be optimal for the job and also make up of steel is important to outcome…
Took a glance at high/low carbon & nickel content in ss…also optimal Oxygen at the laser… without loosing the house!
Funny thing, I was wondering about laser in a vacuum a while back in relation to beam interference…totally counterproductive in this case.
Found this interesting intro to a paper.
Science direct, optics and laser tech, Vol 171, April 2024, 110459.
(understanding the role of Oxide layers on color generation & surface characteristics in nanosecond laser marking of SS).