Laser engraving darkening

[Nigel Morgan]

Hi All,

Any tips to do this other than "Laserdark", shoe polish or something.

Cheers

Nigel

[Dave Fifield]

Hi Nigel,

I've not tried to darken a lasered piece after I have engraved it, but here are some ideas. The best wood for a good dark engraving is alder. Nice contrast ratio. When I need the engraving to stand out, I use laser masking tape (from Laserbits) to cover the whole piece, then engrave it, then fill it with gold or silver paint and remove the un-engraved laser masking tape when the paint is about half dry. You could try black paint or boot polish using this method.

If you don't want to do any filling after engraving, you could try decreasing the power a bit at the same time as decreasing the speed - you might get a longer "burn" on the work. You could also try running it without air assist on (but make sure you don't leave it alone - it could catch fire!).

Dave F.

[Bruce Volden]

Nigel,


I like the colored car waxes, tho some (white) doesn't always work out


Bruce

[Joe Pelonio]

Hi Nigel,

I use laser masking tape (from Laserbits) to cover the whole piece

Dave,

Transfer tape from a wholesale sign supply is about 1/2 the price of the laserbits mask for the same thing. In fact I buy it in 48" logs cut to useful lengths and end up with extra 2-4" rolls that I'd give away if someone in
Seattle area wants to stop by the shop.

Nigel,

I'll mostly use paint, and find that One-shot is best but latex is better than spray cans which are thinner and can bleed into the wood. One shot is oil based and nasty fumes but amazingly good stuff. For denser materials spray paint like Krylon works.

[Doug McIntyre]

If you simply want to increase the darkening a little more than normal - run the engraving out of focus by up to 1/4" either way.

A little experimenting at different focal lengths sometimes improves the job considerably.

[Lee DeRaud]

You didn't mention what material you're working with...makes a bit of a difference.

But for wood, the best contrast I've seen is with the thin baltic birch plywood they sell for model airplanes. This is straight out of the laser (25W ULS, 100% power, 50% speed):
Dragonfly.jpg
Trick is to just burn off the top layer: next layer down is darker, plus the burnt wood (and maybe the glue) turns it jet black. Shoot it with some spray shellac or lacquer to keep the 'soot' from coming off.

[Joe Pelonio]

Trick is to just burn off the top layer: next layer down is darker, plus the burnt wood (and maybe the glue) turns it jet black. Shoot it with some spray shellac or lacquer to keep the 'soot' from coming off.

Lee's right, I also ran into this on a book (Journal) cover that was very light tan thin leather. I burned the lettering into it and the lady wanted it deeper. The next pass was into the hardboard underneath that happened to be black so it worked out nicely.

[Dave Fifield]

Thanks for the tip Joe. Next time I need a roll, I'll go to a sign supplies dealer.

[Nigel Morgan]

Hi All,

Thanks for all the tips, I am working with solid 6mm Beech, every piece burns different, I colour the raster area red to get the best dither effect, some times it burns not black enough so I have to darken that item myself, hence the question. I thought last night of using a wood dye on the area or ink, I need to get hold of a syringe with a fine point, then I can save the rejected items.

Cheers

Nigel

[Roy Barrow]

I do a lot of red alder plaques and the process I use is similar to several mentioned here however....

1> mask the plaque with transfer tape (vinyl sign transfer tape is great and low tack).

2> engrave the plaque.

3> spray the engraved area with a Krylon Clear acrylic to seal the wood grain and prevent bleed...let it dry.

4> then paint with whatever color you wish...I use a brown satin (Krylon is fine) for best contrast.

5> scrape/peel the transfer tape from the plaque using a plastic squeegee (get from a sign vinyl supplier).

6> I use a microfiber cloth and a squirt of GooGone to polish the plaque.

The result is great very high contrast brown that you cannot achieve with laser alone...customers are VERY happy!

[Dennis Perry]

Nigel,

I don't do much engraving but this seems to work ok for me.
I use .25" pre-finished oak over mdf both sides. Not sure of the finish possible a heat activated poly, the finish is very nice on both sides. Cost about $40 4' X 8'.
On a 100 watt machine at 100% speed 20% power dpi 250 same as drawing. After engraving I apply a dark oil based stain and wipe clean. No masking required because the wood is pre-finished.
Piece is 8" X 8", it's the war departments crew.

Dennis

The Crew.jpg

[Raphael Weil]

You guys think this is just two passes on birch? I know the wood is birch and clearly it's mid-second pass. I was just surprised to hear that there was no need to add any sort of external chemical to this process. That's just how birch and alder burn? I can't wait to try this....

smuglabs_1423429043.jpg

[Rich Harman]

You guys think this is just two passes on birch? I know the wood is birch and clearly it's mid-second pass.

It looks to me like it is four separate items placed close together.

[Matt McCoy]

It looks to me like it is four separate items placed close together.

Me too. I don't think it would be possible to obtain that contrast by engraving alone.

[Rich Harman]

Me too. I don't think it would be possible to obtain that contrast by engraving alone.

Oh, I think so. That's because the part that has been engraved is the same color in all four, it's just that three were painted black before engraving. That's assuming those were actually laser engraved, do we know for sure that's what was done?