Engraving signature in guitar fingerboard

[Gary Cote]

I have a client that I am building a guitar for and he wants my signature on the fingerboard done in Mother of Pearl shell. I called a laser place near me and they wanted 100.00 for the engraving. It would be abolut 1.5" long by 3/8"- 1/2" high.
The price sounded a bit high to me.

It is to be done in Ebony wood.
I will do the pearl part and just want the signature cut.

Anyone want a shot at it?

Thanks Gary

you can e-mail me at garynro@comcast.net

[Pete Andrew]

Hi Gary
I'm in the UK and sat infront of a tiny (4 x 2.5 cm) piece of abalone shell which I am going to try to cut into an attractive shape and inlay into some hardwood....
Sounds a little like what you are after, except I've never done this before and I'm trying this out so I can impress a very fine luthier and hopefully get some work off him.
So, if you have found out anything about this process, or if any other people have tried this and have got any tips for me, please contact me!

Pete

[Joe Pelonio]

I have not tried to do anything with that material. When I do something
for the first time I let the customer know that I'll have to experiment and
waste some material in order to come up with the nest settings for the laser.
I normally charge for the material plus $1 minute, something like your job if
you provided material would be less than $50. There is a white pearl shell
laminate available from engraving suppliers so I'd guess I could cut it, but
like I said you never know until you try.

[Lee DeRaud]

I have a client that I am building a guitar for and he wants my signature on the fingerboard done in Mother of Pearl shell. I called a laser place near me and they wanted 100.00 for the engraving.Do you already have the signature in digital form? If they have to scan and clean up from hardcopy, that may explain the price.

[Mike Mackenzie]

We have done this it is not easy because the mother of pearl is calcium it is difficult to cut, Not impossible but difficult. The problem is that you loose a lot of material when cutting the shell so you must compensate for the inlay. the thinner the shell (0.30) the less material you loose. We did extensive testing with the duke of pearl material. We got acceptable results using 030 shell however in fingerboards they need to use 050 because of the curve. You absolutely need conical air assist to cut shell we put 50 psi of air pressure directly down at the cut to keep the material cool.

There is an alternate material that some use that is called Ablam it is a very thin laminated shell onto plastic this material cuts very easy but is very delicate it breaks easy.

The ebony is another issue that is difficult for the laser the reason is that it is extremely hard and has a fairly high oil content. Engraving this material can be done but it requires at least 50 watts of laser power and possibly two passes to get to the depth needed also air assist is real helpful. With our testing ebony can not cut very well at all.

What I would do is to create the graphic make a vector of it raster the pocket into the ebony and then vector mark the shell this will give you the outline to cut with a router or saw what ever works easier when working with the shell.

Here is a pic of a fingerboard we inlay ed using the ablam material.

[Pete Andrew]

Mike's process sounds pretty much what I had in mind - except I had optimistically thought I could cut through the shell rather than just mark it. Still - marking sounds okay if I can't cut through it.

For this type of marquetry, has anyone found that the width of the laser beam comes into play? I have tried doing inlay experiments with mirrored acrylic (which when sanded own flush, then polished to nearly a shine looks akin to mother of pearl), but found a small gap all the way around. Making the cut for the acrylic bigger all round by something like .1mm meant that it could be tapped in good and tight into the pocket in the wood. However the use of the hammer is slightly more out the question when I get around to the abalone! Anyone had any probs or got any wrinkles around this "size" issue?

[Mike Mackenzie]

Pete,

When we do inlays there are two tricks that we use, the first is to mirror image the part to cut and cut it from the bad side of the material. The reason for this is the laser cuts with a slight angle sort of like a V shape if you cut from the back side then turn it over into the pocket the angle goes down and the fit is very nice.

The second is to create and offset. Most laser systems use a 2.0 inch Len's which equates to a 0.005 spot size. When you are vector cutting you are working on the center line IE 2.5 thousands on each side of center. So if you contour you vector cut line to the outside by 0.025 you will allow for the beam diameter and should get a perfect fit into the raster-ed pocket.

Now the other thing to keep in mind is the material acrylic will loose more material than say wood so test the cut measure the part cut and adjust accordingly.

There is one other method that I have found to work extremely well especially for high detailed graphics.

What you do is to setup your graphic file into vectors fill them and raster your pocket into the base piece.

Next take inlay piece and draw a rectangle to fit the area you want to inlay place the parts to be inlay-ed into the rectangle Mirror them horizontally now fill the rectangle with black and the inlay parts with white you should end up with white items and a black background now laser away the black background. cut away the material so that the inlay parts are at the same or close to the same depth as the raster pocket. Then flip the whole piece over and glue it, and clamp it into the pocket. Once dry sand off the remaining material. You don't have to handle small parts this way and the fit is amazing.

Here is a pic done with that process.

[Pete Andrew]

Yes I had worked out doing the cutting of the inlay from the back by flipping it first, and had wondered about how much material was lost in the cut for various different materials. The contour tool I had tried to use, but for whatever reason my Corel draw 9 had produced enormous wayward jagged lines and nodes off to one side when I had tried doing that. Instead I had gone through a process of setting the outline width, making the outline an object, adding a hairline outline to the new object, breaking apart and using the two outlines, of sizes differing by the amount of the original outline width, to cut the pocket and the inlay. Longwinded and prone to probs but it seemed to work.

But cutting out the inlay by rastering away the background and keeping little squiddling bits all together is a really nice idea. Thanks for that one. And all the time I was praying that I would be able to pick those little bits up with some masking tape....! Excellent! And for that process is there any vector cutting involved at all (like to define the pocket, or the inlay)?

[Mike Mackenzie]

Pete,

None thats the only draw back because the rastering takes longer to do than to vecotr cut. However the precision is excellent.

[Pete Andrew]

Mike,

Thank you - I will try that scenario out tomorrow morning. It's mid evening here now, and the red wine is taking its toll. Much too late to play with my laser......

Cheers!

[Brent Perkinson]

Mike,

when you raster away the part so that you can fit in the vector inlay how do you control the depth? or do you? In other words, if I wanted to raster away a groove in a material to a certain depth can I control that depth? How do you make your inlays always fit flush?

[Brent Perkinson]

I think I understand now. You always have to work with a material that will be sandable because of the fact that you can't control the depth. Is this correct?

[Shaddy Dedmore]

You can change the depth of rastering by change the speed and power. Slower and more power would make it deeper. But it also might round over the edges more. Multiple passes will make it deeper.

I think what you're asking is can you control the depth, as in, tell the laser to make it .1" Nope, can't do it. You'll have to pick some settings, measure, then adjust setting according to your needs. The material you're etching will make a big difference too. So your settings will be different for different materials.

Did that help?

[Brent Perkinson]

you confirmed what I thought to be true Shady thanks.


So say I have a material that I know is 1/16 thick and I raster out a "pocket" for this to fit in. Unless I can figure out the correct settings and number of passes to get this exact to the depth that I need, if I need the finish inlay to be perfectly flush it kind of needs to be a sandable material so that when inlayed I can get of any excess material for the "flushness" I am looking for. Is this correct?

[Lee DeRaud]

So say I have a material that I know is 1/16 thick and I raster out a "pocket" for this to fit in. Unless I can figure out the correct settings and number of passes to get this exact to the depth that I need, if I need the finish inlay to be perfectly flush it kind of needs to be a sandable material so that when inlayed I can get of any excess material for the "flushness" I am looking for. Is this correct?I'm a bit unclear on what you're doing and the terminology: by "fingerboard", do you mean the neck (fretboard) or a separate plate below the strings down on the body? If you can, the right answer may be to make the pocket slightly deep, glue in the inlay, and then scrape the substrate down to flush it up before you finish it. If not, possibly use some gap-filling adhesive (CA or epoxy) to flush up the inlay during the glue-up.

I suspect the ebony will be an absolute bugger to engrave anyway. "Plan B" may be to just cut a very shallow (1/64"-1/32") pocket with the laser. That gets you the very precise edges you need up at the surface, then you can deepen the pocket by hand to the correct depth.

(And now I'm reading the back-thread and realize that Brent isn't the guy who originally asked the question...Gary, you still here?)

[Brent Perkinson]

Hey Lee, that is great idea. I didn't think of that. As long as you get the precise lines going for the indent to be taken out you can do the rest by hand. Great idea, takes time off of the laser and gets the result you are looking for.

Thanks A Lot

[Mike Mackenzie]

Brent,

You can control the depth to a point the problem is the wood that you are working with. The same pc of wood can vary from one section to another just because of the grain structure, Oil content, etc. Each pc of wood you work with will have similar settings when lasering but may not be to the exact depth you want. It is always an easier process to go a little deeper and then sand down and finish.

[Pete Andrew]

Still having problems with this inlaying of shell into wood! I have managed to fluke a convincing design using Ablam (abalone shell pieces layered & laminated together), using Mike Mackenzie's method of creating a "rubber stamp" type of "male" out of the ablam and dropping it into the "female" pocket in the wood. Thanks Mike - but now I can't recreate it.... I am trying mother of pearl (not the laminated version - the real stuff) with the same method - and it just falls to bits. The heat obviously changes the composition of the shell hugely, making it incredibly fragile. I have a feeling that the laminated version of these shells is easier to use - any one got a view on this?
Is there any way that I can manage to raster away some areas of the shell without making the whole thing brittle? Should my PPI be really low? Lots of quick passes or fewer slower ones? Nitrogen in the air assist or no need? (like I have some handy....!)
Any help - as always...! - greatly appreciated.

[George M. Perzel]

Hi Pete;
I engraved gary's fingerboard for him and he ended up using a composition filler then sanding as the MOP crumbles as you said. Since then, I have had good luck with ivory-either pre-ban stuff I have or old piano keys. Works great for this type of application.
George