I have just finished this little puzzle for a friend's daughter's first birthday. It's an ideal little present for a 1-2 year old; my 18 month old loves playing with it, and I've made several others for my children which should be finished soon.
It's based on an idea from hitechantics at http://www.instructables.com/id/Name-Puzzle-Laser-Cut/
The technically difficult thing was finding the ideal font - you need something that is nice and evenly thick, with no thinning lines on characters like "m".
I found the perfect font in "Oduda" available for free from http://fontsup.com/design-blog/oduda-free-font.html
While the original instructable had little handles on each piece, I decided against this - my daughter instinctively just turns the whole thing upside down to drop the pieces out, so I don't think it's necessary (and it removes something that she might chew on)..
The entire puzzle is printed in three layers on 3mm Bunnings ply, each layer is glued to the next. The base layer is solid, and the two next layers contain the letters cut out with a 1mm external offset (using Cut2d-Laser). Through a lot of trial and error I've finalised on a way to build it up into what you can see here as the finished product.
1. Cut out the layout.
2. Glue the two top layers of the base together (do not glue to the base layer yet). I found that putting diving weights on top of the pieces is much better than trying to clamp them together, as it's less likely to skew them as they're pressed together.
3. Using a Dremel Shaper/Router table and a #430
1/4" sanding drum, sand off all of the scorch marks from the inside of the (now glued together) top layers, evening out any misalignment from the gluing. Obviously be careful not to take off too much in the process and end up with misshapen cut-outs. Do not sand the outside yet.
4. Sand down the top of the base layer (150 & 240 grit)
5. Glue the top to the bottom. Be very careful in this step not to use too much glue towards the inside near the letter cutouts - any excess is practically impossible to remove cleanly. Use lots near the outside though - any excess here can be sanded back easily (and you don't want any gaps on the outside).
6. Prepare (by sanding) and then glue any 'inside' bits back on (like the inside of an "o" or "a", using the letters to help position them.
7. Sand this all over using 150 & 240 grit, being careful on the top not to damage any fine points (like the inside of the "v" in this picture - which was knocked off in the process and needed to be glued back on). I found that using a 1/3 sheet hand sander (with hook & loop attached sandpaper) was best as it kept it evenly flat as you sand it. Be careful not to sand too much or you get an uneven look (which can be seen in this picture - although it can make it look a little rustic which is nice too).
8. Use a spray gloss lacquer (I used Cabot's Clear Carbothane) to finish the base - 4 to 5 thin coats, sanding carefully with 320 grit inbetween coats. It should end up shiny and smooth.
Then there's the letters ...
9. Glue each layer of the letters together (again I used dive weights rather than clamps to avoid them moving).
10. Where possible use the Dremel Shaper/Router table and sanding drum to remove the blackened edges. Otherwise use sandpaper or sanding block (I like the 3M SandBlaster sanding sponges here as they take the 'edge' off these pieces nicely). For really deep parts of letters (like on a 'k' or 'v') you have to use sandpaper. You probably don't need to take off the black completely - but you do need to even up any misalignment of the two layers, remove any excess glue, and any loose char to help the topcoats adhere. Also give the top/bottom a nice sand as well.
Finally, to paint the letters, you need a primer and then several coats of a non-toxic acrylic paint. While you can probably do this with a brush, it looks terrible (maybe if you are a better painter than I am you can get it looking nice) - you really need to spray to get a nice even finish. I chose to use this as the opportunity to invest in a full airbrush kit (A$190 on eBay) and learn how to use it. You could also use spraypaint from a can - but you will need to get lots - one for each colour, plus your primer, and you'll probably end up spending just as much in the long run.
Airbrushing is actually quite fun, so it's a good opportunity to learn this art (even if it is just to spray flat surfaces nice and evenly).
The basic guidelines I ended up with for airbrushing the letters is -
1. Apply only thin layers of paint/primer. Do not worry about unevenness that appears - fix that in the next coat. Applying too much paint will just end up with a puddle that will look terrible (you'll have to sand it back and start again).
2. Count on two layers of primer, and two layers of colour. You can add an overcoat if you like, but it's probably not necessary.
3. I used a diluted Dulux 1step acrylic water-based primer, diluted with a mixture of Windex and Flow Aid. It was a bit too diluted (which results in the paint 'pooling' on the letters rather than sticking nicely. Next time I will probably use the Vallejo airbrush-ready primer that I have now bought (A$7 from Metro Hobbies in the Melbourne city).
4. For colour, you can buy a cheap set of acrylic paints in a tube from Bunnings (A$12) and mix your own colours to your heart's content. All the letters in this picture I mixed myself like this (diluted with a miture of Tamiya acrylic thinner, flow aid and a dash of water), however the yellow on the "l" was using Vallejo "Game Air" airbrush paint (A$5 from Metro Hobbies). I actually found it much easier to use the paints I mixed myself - the Vallejo seemed much too thick to spray nicely. Next time I might try diluting it a little.
5. Regardless, do not under any circumstances ask your wife her opinion on the colours you used after you've already painted the letters. If you are going to consult, do it beforehand and either tell her to choose the right from the Vallejo catalogue, or make her mix them herself. Otherwise you'll end up cutting out new new letters and starting all over again because she doesn't like the colours you chose.