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View Full Version : I have a laser engraver and an overactive imagination



estill
02-13-2015, 09:45 AM
Let me start with a little bit of background. I volunteer with Special Olympics. I manage an Olympic Town for the Washington State Summer Games. That means I arrange activities and volunteers to keep the athletes entertained between their soccer games. Last year I came up with a laser engraved/cut car kit, to give away. I was able to secure the sponsors for the materials, if I purchased the laser. Well I'm ready for this year, and I have a shiny toy taking up space in my garage. I like to tinker, and on request I was able to put together the camping trailer in the attached picture. That was long introduction to say that I have a pattern on file that I can cut into 3mm plywood and make it bend.

So I'm looking for my next challenge with this laser. I was thinking about trying my hand at designing and building an ukulele out of the 3mm plywood. Right now I'm in that dreaming stage, where everything seems possible because I don't know any real limitations.

The first thing I know it that the body will not be a box. I can do that on my table saw, with no laser required. My current thought is to shape it similar to the youthalele I found here. It's not that complex, and will let me see some of the limitations of the wood. Since the side will end up with small slits in the wood, I'd like to fill them with some type of urethane. So this leads me to my first pondering/question: how much do the sides effect the overall tone?

The next question I have is in regards to the soundboard. 3mm and plywood seems overly thick and stiff. My thought is to basically burn an inverted sunburst onto the backside (inside). Think dark in the middle with light on the outside. With the laser that pattern would result in a gradual thinning on the wood from the outside in. Bracing for the bridge would be accomplished by not burning the wood in that area. As for the sound hole, other than it won't be round I'm undecided.

What about the nut and saddle? I know bone is the preferred material, but what about acrylic? I have scraps of that from other projects.

Finally I'd like to do something special with the fretboard. Right now I don't know what. So my question is the usability of the plywood. It is too soft? My second thought about the fretboard would be to use the laser to cut the slots. The problem I will run into is not getting a uniform depth. When it cuts too deep can I glue in the fret wire?

The neck will be laminated plywood layers. I have a few ideas for making it key into the body.

Right now I'm completely undecided on if I even want to attempt this. So I'm asking for any feedback or suggestions.

Eric

Brian1
02-13-2015, 11:03 AM
Hi Eric,

Congratulations on the cool new toy. I've never built one but StewMac sells a kit
http://www.stewmac.com/Materials_and_Supplies/Kits/Ukulele/Tenor_Ukulele_Kit.html that might come in handy you can also get DIY DVD. I would look at that first.

Have you gone to You Tube they seem to have every step of the building process there.

I was also thinking recently that a laser engraver could possibly engrave the buttons on tuners. Just a thought.

Titchtheclown
02-13-2015, 11:26 AM
Stephen McLean makes extensive use of his laser in his videos.
There is also a laser cut folding ukulele on instructables��
Thankfully there is no committee out there defining what a ukulele is or banning people from having a good time building strange objects and calling them ukuleles. If there was, I would be in trouble.
Check out some of the build blogs here and the web pages of many of the people who post here, which many of them usefully put in their signature line.
Cigar box nation and instructables are also fun places to look.

Michael Smith
02-13-2015, 12:22 PM
Sounds like it could be fun but cutting out the parts is the easy part of making a decent ukulele.

geetee
02-14-2015, 01:41 AM
Disclaimer: I am not luthier, so this is just a guess. Your soundboard sunburst burn should probably not be inverted, so it will gradually thin towards the edges. Maybe a real luthier will chime in to confirm or deny.
Have fun with your build.

ksquine
02-14-2015, 06:39 AM
I'm so jealous that you have a laser cutter!! just think of the inlay work I could do
Do the sunburst on the outside so it looks like a sunburst finish. Thicker in the middle and thinning toward the edges like an archtop guitar. It could look cool to do a raster-ized sunburst
I don't know what type of acrylic you have for a saddle. Hard acrylic should be ok. Maybe make it removable so you can try different materials
Plywood fingerboard??...maybe. Hard smooth birch ply might work. Soft fuzzy luan ply...forget it. The frets are pressed into the slots so you need something hard enough to hold the tang.
No prob cutting the slots too deep, but you want a good clean, straight sided kerf 0.024" wide for typical fret wire. I'm not sure how well a laser can do that. Maybe you could use some hard Corian make the frets by lasering out everything between frets, making a one-piece fretboard. It wouldn't last as long as metal frets, but nylon strings are pretty soft so it should last quite a while

Kevin Waldron
02-14-2015, 02:21 PM
You will find it very difficult to laser a sunburst....... what your seeking is a 3D laser cut which takes forever in the real world. A laser can only vary the Z height for photo's etc.with a grayscale picture usually produced by a software like Aspire, Artcam, and several others. ( Z scale can always change but not to the point of making a picture without the proper file. ) I'd refer you to the OLF forum if you need more detail about fret boards etc. and if you have and interest in 3D laser work Sawmill Creek.....

http://luthiersforum.com/forum/index.php

http://www.sawmillcreek.org/

We've done a lot of both kinds of laser work.

Blessings, in your quest.

Kevin
761257612676127

Booli
02-14-2015, 03:54 PM
If I had a laser cutter and/or a 3D printer, I'd probably just never leave the house ever again.

Wish I could 'play' with one of either, but there are no 'maker-spaces' near me....



There is also a laser cut folding ukulele on instructables��


Some links are per what Titch said above (made mostly from bamboo):

http://www.instructables.com/id/Constructing-the-Laser-cut-folding-ukulele/

http://www.ponoko.com/design-your-own/products/folding-ukulele-soprano-size-bamboo-plywood-kit-blonde-color--10949

http://www.designboom.com/design/laser-cut-folding-ukulele-by-brian-chan/

CeeJay
02-14-2015, 06:04 PM
You will find it very difficult to laser a sunburst....... what your seeking is a 3D laser cut which takes forever in the real world. A laser can only vary the Z height for photo's etc.with a grayscale picture usually produced by a software like Aspire, Artcam, and several others. ( Z scale can always change but not to the point of making a picture without the proper file. ) I'd refer you to the OLF forum if you need more detail about fret boards etc. and if you have and interest in 3D laser work Sawmill Creek.....

http://luthiersforum.com/forum/index.php




http://www.sawmillcreek.org/

We've done a lot of both kinds of laser work.

Blessings, in your quest.

Kevin
761257612676127

Oh wow ...I've just read a post which reads to me how mine must read to the rest of the world...........I've sorted it into words I do understand and those I don't ...Guess which is the bigger pile ....and I frigging love it .....especially if it has anything to do with Lasers .....Flash ...Ah Ah ...he's the sav --i ---our of the universe...... whoops sorry ......

rudy
02-16-2015, 08:00 AM
Nothing particularly wrong with unbraced 3mm baltic birch ply for a top / back. You might get some ideas from one of my recent projects:

http://www.bluestemstrings.com/pageGuitarThreeString.html

RPA_Ukuleles
02-16-2015, 09:15 AM
You will find it very difficult to laser a sunburst....... what your seeking is a 3D laser cut .... A laser can only vary the Z height for photo's etc.with a grayscale picture


Kevin, you say vary the Z height.? My laser varies the power level to create multiple depths of engraving. Are we talking the same thing here? Varying the Z height changes the focus point. Can you elaborate?

Also, it's quite easy to create a grayscale file like a sunburst in Adobe Illustrator or Photoshop. Additionally, multiple passes are another way to get a deeper burn.

OP, keep in mind that bracing is stiff because of its grain direction. If you simply vary the thickness of a piece of wood to simulate bracing, you won't necessarily get the same stiffening as you do applying bracing. Plywood is a bit of a different case as it has multiple direction plys. But still...

Edit: I'll mention... I have had limited luck in laser cutting fret slots. Wonderfully accurate in placement, but the nature of wood and grain usually results in uneven depth of cut. Ebony is most consistent, but still not an ideal way. Where the laser excels is in vector cutting. Cutting out shapes is fast and accurate. Raster engraving is often a crapshoot.

Kevin Waldron
02-16-2015, 04:53 PM
Rodney,

To get a 3D file ( file with 3D +/-Z) for laser, software like Photoshop want read 3D files (Iges,3DM,3DS,Step,RLF,STL,etc) and produce the needed laser file that I'm aware of. We own two Universal Lasers and you are correct that the power is varied to get some of the 3D effect but the Z height is also varied. Another way to possibly produce laserable files would be with new programs like Rhino3DPrint where and object is sliced in to various Z Height layers.... haven't tried using the program this way but it should work.

As far as cutting fret slots....... it is not an easy thing to dial this in. The wood color, density, cut of material, and the oil in the material all play factors in how it will cut. Not sure your power but this makes a fairly substantial difference in cutting...... (we have 150 watts) it's not just about power but also the PPI. Even the lens used will make a difference. Normal lens that most use for our style laser is 2.0........ we use a 4.0 lens. It took us a long time to dial this in but we finally did........ We stopped doing this kind of work several years ago, I no longer enjoyed doing it.
Including and example......

Blessings,

Kevin

7620176202

estill
02-17-2015, 06:08 AM
My apologies, I went away for the weekend thinking I would have internet access. Coverage was spotty, at best, in our room.

I have a 50W Chinese laser, and I agree that a raster image involved a certain level of luck. I've had my laser for a year now. I'm slowly learning the limitations. I have a couple of lenses, and I find the 3.0" on the most forgiving. Most of the time I can do both a vector and raster in one job and be satisfied with the results. On wood I typically just engrave black images. I'm just now starting to play with photo's via converting black and white image into a 1 bit color pallet. I'm just going to say that process is interesting, and i need to do some type of a gradual fade with reference points to see what is really happening to the material. What I was wondering is would thinning the wood help with the volume and sustain? Or am I over thinking this, and should just build one?

I have read through the folding uke, and the "laser cut ukulele" on instructables.com. bluestemstrings.com has been a great resource as I have read through both the ukulele and 3 string guitar, thank you.

I think the other answered questions were: I have 3mm birch plywood. For the acrylic, yes it is the hard type. My scrap pile has a few colors in it, but there is a place here that sells their scraps by the pound.

I'm going to try and put together an image of the top, over the next couple of days. I'll post it to get some feedback once it is complete.

Eroc

estill
02-18-2015, 06:32 AM
Here is a very rough drawing of what I have been wondering about. I can easy engrave/raster the attached pattern onto the plywood. My thought is to hide this "image" on the inside of the uke body. This leaves the face of the body untouched for me to finish.

It you look closely at this image you will see that it is entirely comprised of black dots. While in theory each dot is lasered to the same depth, in practice the closer spacing produces a deeper engraving. At least this is the experience I have had with my laser and a 3.0" lens.

Eric

RPA_Ukuleles
02-18-2015, 11:41 AM
Yeah I think you could use a halftone or dither pattern to get the results you're thinking. That way the laser doesn't have to vary the power. However, you would most likely want the thickest par of the top to be under the bridge, and thinner toward the edges. So you'll actually want an inverted sunburst, with the lightest area centered under the bridge.

rmaine
03-06-2015, 09:53 AM
OK way cool idea.

First question, how many and who are your target recipients?


Assuming that you wish to stick with the 3mm ply as much as possible.

Size soprano Ė very materials efficient.

Shape Ė go with the classic pineapple uke shape. One strip of wood using the laser cut lattice hinges at the bouts (curvy parts) just like you used in the trailer kit. Give it a slight trapezoidal side profile; cut the ends a few mm narrower (take it off the bottom edge) near the heel to avoid creating standing waves i.e. wolf notes.

http://www.instructables.com/id/Curved-laser-bent-wood/

Linings Ė probably donít need them with 3 mm sides. I have an ancient little arch back uke on my desk with sides and top less than 2 mm and no linings at all. I would just pre glue a few little blocks at the start and stop of the bouts on both the top and back to act as locaters for the sides, setting them in from the edges by the 3mm side thickness.

Back Ė Flat with little locator blocks at the beginning and ends of the bouts

Top Ė you donít really need to do anything special to the top. Just pretend it is a woodenheaded banjo and go with it. Add little blocks to the top just like the back.

Neck Ė Spanish heel would probably be easiest to cut and assemble. Maybe add a locater pin in top and bottom of the heel paired with small holes in top and back to position things.

Nut, saddle, bridge Ė Your acrylic would probably work just fine for both the nut and saddle. Although many an ukulele has gotten along just fine with a wooden nut and one piece wooden bridge/saddle, probably not from soft plywood though.

The bridge is your first trouble area. I would probably splurge for some hardwood molding near the correct profile then finish it off with a router. Chop it into appropriate lengths and pre glue it to the tops. Actually I would probably find a friend with a router table on a ukulele blog to volunteer to do it for me in exchange for a finished kit.

Next in line for hassle factor will be the fretboard. Even for a cheap novelty gift kit the fret board will need to be harder than plywood, maybe some wood grained formica? Cutting fret slots, pounding in the frets and leveling them all takes time and skill, and fret wire isnít cheap. All of this is why plastic fingerboards are common on cheap ukes.

Finally we need to look at the peghead and tuners. Even cheap friction tuners arenít cheap if youíre giving lots of them away. Violin type pegs will work and can be home made, but not with a laser cutter. In addition they require a certain amount of skill on the part of the player to use.

At this point I have no good suggestions for the fretboard or tuners other than begging some place like StewMac or LMI or just a thought!!! Grizzly Tools is headquartered in Bellingham. The owner and President Shiraz Balonia is a guitar maker and Grizzly offers a soprano uke kit for $26.95. The kit has a pre-fretted finger board and cheap tuners, you could try hitting him up for a corporate donation of fingerboards and tuners for the special Olympics.

Just a thought.

I am sure I am missing many other details that need attended to, but a laser cut uke kit for a Special Olympics event is a pretty cool idea and most of it is doable with your laser cutter.

estill
03-06-2015, 11:36 AM
The answer to the first question in simple. I'm making one for me. If it turns out well and people like it, I'd consider going into a very small scale production.

As for making these for Special Olympics that would be awesome, but at the event I manage I have maxed out their attention span and abilities with a wooden car kit. (see attached picture 76996) Custom paint job are achieved via magic markers, after that snap out the pieces and glue them together like a 3d puzzle.

As for the size and shape I've settled in on concert, and a flat bottom pineapple. I'm hesitant to try and bend on piece around the entire perimeter, so I've cut the tail end flat. Instead of something like your blocks, I'm going with something similar to traditional kerfing. I've taken my drawing of the back, and ran a parallel line 3mm in from the edge. So it will fit perfecting inside to the outside pieces. This piece will only come in 10-15 mm from the outside edge so as not not add much weight. I figure this will give me a little extra material for rounding the edge.

The bridge and nut are probably going to be trial and error. I have a router, and various scraps of wood if I need them. My design will allow for them to be swapped out.

I've gone ahead and purchased the remaining hardware. I have to admit that I went cheap, and split the pieces between CB Gitty and evilBay. CB Gitty has some fret wire that is not that expensive so I'm going to try a fret board out of plywood first. If it doesn't turn out, I can always look for a pre-made fret board.

Thanks for the input.

tinkeranything
05-24-2015, 11:59 AM
I've been working on a laser ukulele project for a while now, and I've never been satisfied with the sound from mulit-ply materials. Right now I'm using 2mm bamboo in single-ply from Plyboo out of San Francisco. They sell 12" x 48" pieces and I can get an entire ukulele out of that. I am interested in your idea to raster a thinner area onto the material to improve the resonance, but I'm not sure how well it will work. You want to actually get some depth of cut, and that could take a very long time and may cause the material to weaken in other ways, but I am so curious to hear how it works.

If you want to see pictures of what I'm doing, check out my pictures here: https://flic.kr/s/aHsk1oWdg1