Lasering inside of bowl - cleanup

[Joe Sheble]

I've been using a laser to personalize bowls, engraving a message or a name on the inside bottom of the bowl. I do this after shaping & sanding, but before any sanding sealer or finish. I've noticed though that after lasering, and applying either sanding sealer or my finish, or even giving it a wipe with denatured alcohol that the soot from the lasering gets picked up, and inevitably ends up in some of the open end grain on cross sides of the bowl side/curvature. Does anyone have some advice on how to prevent that? I had tried sanding it afterwards, but then you loose some of the coloring in the engraving itself. So any helpful tips or advice would be great.

Typically on these bowls I shape, sand, engrave, and then use Parfix 3408 or 3460 for the finish.

 

[Richard Coers]

You should turn down the laser power or speed up the travel to reduce the resin stain. But in my opinion a thinned coat of finish would be the way to make life easier for you.

 

[Joe Sheble]

My only concern of applying something first would be the flammability of it. I had tried messing with the power, but I like a deep dark engraving.

 

[Doug Freeman]

Just thoughts:

Might try a microfiber towel. They are great for removing sawdust, and you can rub hard but not abrade anything.

Maybe hi grit paper, 800 or so, or hi grit sanding sponge that flexes, pulled around a round object.

 

[Mark Jundanian]

If the finish is cured it won't be more prone to ignite than the wood itself. So try a test piece.

With my branding iron I lightly sand with the last grit. This cleans up the soot and singed wood w/o removing the brand, but the brand is probably deeper than the laser engraving.

 

[Brian Gustin]

Get some of your chosen finish on a lint-free cloth or towel, then just dab it in over the engraved portion - very thin coat just enough to saturate (and pick up loose stuff) and I'd think it would reduce or eliminate the "smear" - its what I do with my lasered engravings in wood, although I don't do it in bowls (just on flat boards) so maybe I just don't notice any smear since there's no end grain (though there is open pore on some woods) once that dries should be able to sand and detail and finish without getting the black stuff into your open pores.

 

[Karl Loeblein]

Wonder if a strong blast of air from a compressor using a small nozzle might help blow the soot out from the pores.

 

[Dennis Weiner]

There are two approaches to solving your problem.
I epoxy cracks with dye or mica powder. When sanding, the dust from this combo will invariably embed in open grain wood. To resolve this issue, I use a steady flow of compressed air over the sander and this blows most of the particles away during the sanding process. In the remaining areas, if any, I directly use the blower at close range until there gone. THE OTHER: If this operation is not physically possible, alternatively I put a few coats of finish on prior to filling and sanding until the pores are closed. Similar to the laser process, the dust, whether mica powder or laser residue should slide across the grain when an air blast is applied. This should clean up your burnt laser debris similarly to my mica-epoxy sawdust. I then would continue the finishing process.

 

[Richard Coers]

My only concern of applying something first would be the flammability of it. I had tried messing with the power, but I like a deep dark engraving.

I had a Universal Laser for years. Fire is not a worry. I thought you weren't happy with the current process, I thought you would be open to suggestions. You don't have to burn a bowl to experiment with the finish, just do it on a piece of scrap. Burn it in 2-3 lower power settings for more depth at lower wattage.

 

[Dennis Weiner]

@Joe Sheble you may wish to try water-based poly which is non flammable. Water base poly comes in flat, semi, and gloss. I dilute it to a 50-50 mix. Apply it with a lint-free cloth, then I immediately rub it off with a different dry lint-free cloth. “No runs, drips, or errors.” It requires more coats, but it drys fairly quickly, but you may need to lightly sand between the early coats. Finally you can buff with the Beale system it if you wish.

 

[Bill Blasic]

I have never run into a problem lasering through lacquer, walnut oil and even ca glue. When using the laser with or without finishes I use a fine bristle brush to clean the burning. Advise above to lessen power or speed up the travel is good advice. Tight grained wood is also a way not to get burnt dust in the grain. Also my laser uses an air pump that keeps flame away even at the full power levels.