How can I handle soft wood in middle of hard wood

A lot of time, I will build tops to my boxes made with two or more types of woods. Unfortunately, in some cases, the two woods are so different, that trying to burn a large area causes a crater in the less dense piece of wood, that makes it difficult, if not impossible, to put in inlays that are very thin. As an example, the two photos show one top, hard Walnut and soft Padauk. Trying to lay in the cardinal image would cause the so called crater effect. Splitting up the image is NOT a great idea, trying to re-align those would be hard. This example shows only two different pieces of wood

, sometimes I use up to 5 or 6.

It would be interesting to have a mask layer ( or layers ) that I can apply to the burn to reduce the % of burn when on the softer woods. That would avoid the crater effect. Any other ideas?

Do you have a photo of the crater effect and impact that you’re trying to avoid?

It’s hard to show, but remember, most inlay veneers are 1/32" of an inch. If your inset is going down 2/32", when all the rest is at 1/32", it delivers a soft spot on that section. The opposite effect, instead of a crater, you get a hill, when the smaller section is Harder than the larger section, the laser doesn’t cut as deep, and thus, you get a bump, or hill. Again, putting a 1/32" veneer on top of that causes a bad situation when you try to sand down flush. I haven’t got any tops ready for lasering today, but I’ll try to get one soon. It really isn’t a hard thing to visualize. ( Also… if you laser over a glue line, well… that creates similar situations )

I think I see what you’re saying. So you have two types of wood in which you’re creating a recess for a common inlay. The soft wood recesses farther than the hardwood with the same cut settings. Correct me if something wrong in this.

Can you elaborate on why this would be hard? To me the splitting and alignment should be fairly trivial. The harder part of this would be the alignment of the design to the correlated area of wood but perhaps that’s what you were referring to. If the areas of wood have precise dimensions then that would make this more doable.

  1. split the design into parts that correlate to wood type
  2. put each part onto a layer matching the wood type and proper cut settings
  3. align job to work material
  4. burn

The masking idea that you proposed would require the same level of precision at the end of the day.

Alternatively I suspect a mechanical wood removal solution is going to be simpler.

If I am following you correctly…
Your pieces of a softwood are of the same dimension completely across a section of your panel.
If you are using a drawing program you can overlay a faint rendition of your image over a rendition of your panel. The softwood portion can be isolated and develop layers which would consist of the bird being done in three layers. That is assuming you only have one piece in the panel that is soft. More pieces of softwood multiplies the effort.
Wouldn’t it be much simpler to use wood of a species that has different hues in the same panel? Therefore eliminating your original problem.

I think you have the essence of the problem, but the solution is not trivial. In this example, with only one “soft” or “hard” segment, breaking the image wouldn’t be hard, on simple images… BUT, this process would only work well if I had the patience to do this. With a camera in the laser field showing the project, I would think it could be easier to extract the soft or hard wood pieces as trace ( which we do all the time with an image we import, so it is possible ) and then produce the mask much easier from that. But thanks for the alternate idea.

This will depend on your tolerance for error. I had assumed low tolerance since you’re worried about minute differences in depth. I’d assumed even a small misalignment of the wood would be an issue.

Right now are the dimensions of the hardwood and softwood mechanically precise? As in do they have known and reliable dimensions and placement or possibly already in a design file?

If so, you could use that design to break-up the inlay design relatively easily.

Also, this would allow you to position the work material in a way as to ease alignment.

If the hardwood/softwood relationship is done with a lot of handwork then that makes this harder. But based on what you’re implying about precision requirements maybe not so bad.

Well, if the camera doesn’t give you a somewhat precise image ( at least to a mm ), then not sure what the purpose of the camera would be. But between you and the other gentleman that responded here, you gave me a few ideas to experiment with, and if successful ( or even not ) I will update this and present my findings. Thanks!

The camera when used for alignment I think could reliably get you millimeter precision. However, between the capture and the tracing process I see more error being introduced and potentially cleaning up of the trace required.

Good luck with your experiments. Let us know how you fare.

Have you considered making a depth map out of your cardinal image? Different shades engrave to different depths. I would imagine you drawing lines over the image to delineate your different wood type areas, then flood filling in different shades of grey for the different types of wood.

Hmmm… that IS one possible solution, though a mask would be better. I am trying to minimize the effort, I use these a lot, and having to keep making depth masks for every combo sort of negates the low cost I am trying to maintain. My time is money … BUT, I’ll keep that in mind.

I engrave my mark on the bottom of bowls so it is one solid chunk of wood so my mileage may be different than yours. That being said, I finish the piece completely but more casually do the area where the laser will burn. I figure the burn is more to the finish though I can smell wood. Always looks even across winter and summer grain. Only concern I have with grain is Will It Be Harder to See Here or There ? Finish is either or both of shellac and MinWax Antique Oil Finish. Usually at least 2 coats on the to-be-engraved bottom.

Unfortunately, I am inlaying, so the processes are quite different. I have to burn down into wood to place my inlays. I try never, never to burn through finish, but that does work for you, then great!. Thanks.

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