Tag Archives: laser cut

118: Crackers

Full disclosure, guys – I did not expect this week’s experiment to work.  I figured in the worst case, it would satisfy a curiosity, and I’d get to eat hand cut homemade crackers with dip.  Ryan, on the other hand, didn’t know why I was questioning it, and thought cutting cracker dough with a laser would be a low power, simple task.  The answer was somewhere in between.

Simple ingredients, simple recipe!
Food blogging, here I come!

I’ve never made crackers before, but I had everything on hand in my bare cupboard for this recipe from The Kitchn.  As suggested, I mixed up the dough, then split it in half before rolling it out.  I took advantage of the two batches to come up with two different designs (which Ryan graciously vectorized for me.  I admittedly started this project a bit late in the evening and need help.)

Rolling it as thin as possible – the dough is springy, so you can’t work it too fast. It needs to “rest”
I layered the dough on parchment paper, and on wood.

My goal for rolling out the rough was to keep it under 3mm, 1.5 ideally.  The thinner the dough, the crispier the cracker.  I rolled it out on parchment paper – food safe, and bad things wouldn’t happen to it in the laser, just a little singeing.  I then put it on some plywood for stability, and to prevent the laser from reflecting back after it hits the honeycomb bed, which might not be the cleanest.

Pro tip: I learned when rolling out the second batch of dough that it was actually easier to roll the dough between two pieces of parchment paper when it got thin.  It was easier to flip, it seemed to spring back less, and it stayed moister while I worked with it.  I did remove the top later of parchment when I put the dough in the laser.

Test cuts – third time is the charm!  Interesting thing about cutting the dough – it was a little “sparky.”  Naturally dough isn’t homogeneous, but instead a mixture of ingredients.  The laser reacts differently to this ingredients, which created tiny little light flares.


Less than 3mm thick, I’m thrilled!

So, I didn’t think the laser would cut the dough at all, Ryan was thinking it would be a breeze – maybe akin to paper.  It took a few tries to get though the dough, and the right answer was some there in between – we cut at 100% power, and a slow 8% speed.  I didn’t roll it perfectly evenly, so the dough was thicker in some parts, but it still all cut.  And my test measurements were all under 3mm thick!

Heart shaped vent holes – totally a pain in the butt.

The first design was this funky hexagon shape, with little 1mm hearts cut in for venting, so the crackers wouldn’t puff.  Officially, the design is too complicated.  The outer shape is fine, but the hearts took too long to cut, and didn’t come out easily.  I actually baked the hearts in place, and then Ryan popped them out after.  And the length of time tried out the dough quite a bit since we had to have the exhaust on.  with set up, test and cutting, it was in our windy laser for about 45 minutes.  The edges of the crackers were trying to curl up!

Triangles!  Classy appearance by my phone.

Second batch we went a little more simple – a nice rounded triangle with asterisks cut for venting.  They ended up delightfully mod looking, and in were in and out of the laser in under 15.

Light toasted!

Baking is pretty straight forward, but the crackers are easy to burn as you can see.  The first batch were a little extra crisp, but edible.  The second back felt under done while they were still hot, but after they cooled they were perfectly crispy.  So, watch them closely, and make sure you let them cool, unless you are going to a crispy-chewy combo.

Midnight snack.  Homemade crackers, but I totally bought the artichoke jalapeno parmesan dip, the leftovers of which had disappeared by morning.

Verdict – The recipe was tasty but be forewarned, the crackers themselves were not airy or flaky.  They were dense, and reminded me of pita chips actually.  I may have over kneaded them.  This is a fun example of too much tool for the job – a knife easily cuts the dough.  But this would be a fun recipe to perfect for fancy dinner parties, potlucks you want to impress at, or those times you want a crunchy snack and don’t want to leave the house.

117: PC Case Engraving

To ring in the new year, and celebrate the ten year anniversary of my previous build, I decided to build a new PC. Back in 2007, it was two years before we even started playing with lasers. This time around, I knew for sure I’d be laser engraving some piece or another. I’ve engraved a few macbooks and other portable devices, and I’ve even engraved a custom wood faceplate for a friend’s ATX midtower. So I’ve been pretty excited about the idea of engraving something on my own machine!

Over a few weeks in January I did the research, collected the parts, and then planned a small “build party” with some of my local PC enthusiast friends so we could put the machine together together. Hey, it only happens once a decade or so, that’s a pretty good excuse for a shindig, yeah?

From left to right, Brenn, Jen (<3), myself, Maul, Ray, and Mark. Also not pictured: Maul’s bro Joe! Thanks for the photography, Mark!

Together we had dinner, built the PC, played some couch games, and mulled over a few remaining questions. What should this new build be called? What part of the case will be laser engraved? What are we going to engrave on it? I was so wishy-washy on the name decision that I couldn’t even settle on it before the party was over. Furthermore, I wanted the engraving design to be related to the name, so I couldn’t really come to any decisions on that front, either. But we were able to figure out what part to engrave, and as it turned out, the answer was nothing.

Fractal Design’s Define C case is sexy, but made out of questionably engravable plastic.

The Fractal Design Define C is a sexy, sexy midtower ATX case. I love the shroud, I love the quiet, and I love the flat textured front. I like simple, unassuming case designs, and I wanted to continue down that road after my last build in an Antec P180B. But when we finally dug into the case, I learned a few laser-unfriendly things I could probably have sussed out from reviews online if I had been more thorough.

The front of the case is not an anodized aluminum plate, and it’s also not easily detached from the surrounding plastic chassis that covers the front exhaust system. It’s made out of the same plastic—it’s very pretty, with a subtle vertical brushed texture, but it’s still just the case plastic. Because the textured surface isn’t repeated anywhere on the inside (or indeed on any other external surface) I wasn’t going to be able to do an inconspicuous engraving test. So I wouldn’t be able to engrave the front plate, but what about the window?

On a quest for extreme sound dampening, my previous PC build didn’t have a window at all. But over the years I’ve kind of missed being able to peek in on my parts, so this time I bought a case with built-in acrylic window.

With a power shroud for modesty and excellent cable arrangement, who wouldn’t want to peek inside?

Unfortunately, there wasn’t going to be an easy way to test that material inconspicuously either, and with the  engraving quality difference between cast and extruded acrylics, I didn’t want to gamble.

When I looked closer at the acrylic window, I noticed there was a lip on the inside, one that would fit a secondary piece of acrylic just fine as long as the measurements were correct. So I did a couple of sizing tests with some old pieces of acrylic, got my measurements spot on, and settled on a solution: cut a separate piece of cast acrylic and snap it into the existing acrylic window. I wouldn’t technically be engraving the PC case after all, but the finished piece would still look as good. As a bonus, I’d be able to easily change out the acrylic in the future if I wanted to change the design.

Amusingly enough, it was mulling around design ideas that led me to my final decision on the name of the machine. I’ve always been a fan of the Metroid series, you can see it in some of my other projects. Most game servers I host have names based on “Maru Mari”, and you’ll be connecting to “Varia” if you try to stream content to my television. I had a feeling I’d end up going with the Metroid theme again, but it wasn’t until I thought about how much fun it would be to engrave the cold steel corridors of Tourian into acrylic that I really landed on it.

The full map is too big; I’d have to fit it in this cyan rectangle

Tourian is a big map. Well, it’s not big, but its hallways are long and the vertical shafts are all a daunting climb. I’d have to compress the map pretty significantly to make it fit the relatively tiny space I had for my acrylic window. To make matters worse, halfway through the design I realized I had laid out the template wrong and was designing for the measurements in landscape instead of portrait. But after cutting a few rooms in half (and completely excising the hallway before Mother Brain’s chamber) I was able to make it fit.

The final compressed map, corrected to a portrait aspect.

I added a few additional details (the opening text scroll and an excessively big title in the original typeface in the corner) and the design was finished. I cleaned up the acrylic, seated it in the window’s lip, and used a tiny bit of clear packing tape on the inside corners to make sure it wouldn’t somehow come loose.

A mockup of what the case might look like with the final design.

The panel looks great when it’s not connected to the computer, but as it turns out, I should look into buying some motherboard-powered LED strip lighting to brighten up this design. Most of the photography here is cleaned up to make the engraving visible, but it’s much more subtle than that when properly installed on the PC.

This door is all that’s left of a completely deleted room. Don’t tell the purists!

The end result may be disappointingly dim, but I still had a blast manipulating the Tourian map in a way that wouldn’t compromise the basic layout, and I will definitely be using what I’ve learned on this project to make some more “window inserts” for this case in the future. Once it’s lit up, the design itself should really shine, but for now it still makes for some pretty fun close up photography!

The engraving fights with the inner bits just a little more than I’d hoped.
I love that the escape shaft coincidentally has its own murky yellow and green lighting.
This example clearly shows how dim the engraving is compared to the LED-lit components inside.
A two character 8 segment LED readout hides in Tourian’s O.
One Metroid, permanently frozen.

109: Edge-Lit Acrylic

I’ve been playing a lot lately with a new toy I picked up from Inventables: a powered LED strip for edge lighting acrylic. It’s made in particular to work in tandem with specially made acrylics that transmit light efficiently, but I’ve found it works really well with simpler transparent and fluorescent acrylics.

The first dual-layer design.
The first dual-layer design.

My first test was with transparent orange material sourced at the Aurora Public Library’s Makerspace—check it out if you’re local!—and it seemed appropriate to design a little sign for the space as the test. Because the LED strip is designed to snap to the edge of a 1/4″ piece of acrylic and I only had 1/8″ material available, I decided to split the design across two layers of acrylic. The front layer included all of the vector engraving and the back layer was just the main title text filled. The resulting look is striking, but using two transparent layers means you have to be extra careful not to let any fingerprints or dust get in between.

The short sign lit up easily.
The short sign lit up easily. Please ignore the Macbook!

Around the same time, I was working with a local artist to create some wall décor based on the classic Pac-Man maze. We agreed pretty quickly that the lit effect would look great and settled on some fluorescent blue acrylic. The first several tests confirmed that the two layer effect would be excellent; dividing the pellets, ghosts and other objects from the maze walls might not be very visible in the photography, but it’s a really neat trick when you’re examining the piece up close.

A small cross-section of the Pac-Man design in two layers.
A small cross-section of the Pac-Man design in two layers.

One concern I continue to have is whether a single LED strip will be able to illuminate the entire flourescent blue acrylic sheet—this piece is 16 inches tall, towering compared to the 4″ makerspace sign. A quick test on some scrap acrylic shows that the light visibly dims near the top, but I won’t be able to know for sure how the final piece will look until a last-minute shipment of materials arrives. Speaking of that, here’s a pro tip: don’t assume you’ve got all the materials you need until the day you’re scheduled to cut! Always check, even if it’s something you always keep in stock, like the black cast acrylic that was supposed to be the backing layer for the finished Pac-Man piece.

A later single layer test cut with rounded vector engraved maze walls.
A later single layer test cut with rounded vector engraved maze walls.

Edge lit acrylic is a great look, and I’m might have to investigate the “EndLighten” brand or similar substrates to maximize light transmission. I know I’m also going to be looking into portable equivalents; this hardware has to plug into a wall. I’m sure that’ll be a post in the future; until then, look forward to an update on this post with additional pictures of the finished Pac-Man piece!

This crazy square panorama shows how the lighting falls off near the top. We'll see how it looks in the finished piece!
This crazy square panorama shows how the lighting falls off near the top. We’ll see how it looks in the finished piece!

108: Preparing Laser Cut Wood for Paint

Scott at work!  Mixing the green wash (there is a touch of gel medium in the glass too)
Scott at work! Mixing the green wash with our trusty note taking and testing plate.  

This month I thought it would be fun to add a new skill: properly preparing a wood surface for painting.  I have painted laser cut wood in the past (Week 64 is a notable example), but honestly, the preparation and finished result is not what I’d consider fine art.   So, with the help of Scott Sherwood, Fine Art Conservator, we will learn some basic first steps to preparing unfinished laser cut plywood shapes for paint.

week 108

Supplies you will need:

  • Laser cut wood shapes
  • Grain filler (I picked up DAP Plastic Wood from the local DIY store)
  • Scraper or palette knife (we used a metal spatula!)
  • Gesso (Liquitex is Scott’s favorite, easily attainable brand)
  • Water
  • Paper Towel
  • Brushes
  • Foam roller
  • Sandpaper (240 or 400)

Step 1:  Cut your shapes

Our professional work surface
Our professional work surface. Apologies for the poor photos – I was not using my own camera, and we hopped from natural light to fluorescent light too much.  Another lesson learned!

For ease, I precut some plywood into shapes I had on file – a bird, the whale and a couple different quatrefoil examples.  I also had a couple plywood circles left over from an earlier project and threw them in the mix.  Cutting first means the edges will get some over paint and need to be finished at the end – if that is a problem or you have a particularly intricate shape, I’d suggest preparing the surface and possibly even applying the background color before cutting.

Step 2: Determine whether you have open grain wood or closed grain wood

Closed grain on the left, open grain on the right
Closed grain on the left, open grain on the right
Raking the light across the surface makes uneveness pop right out
Raking the light across the surface makes uneveness pop right out.  The ampersand wasn’t cut for this project, but something I had laying around.

Some wood simply has more prominent grain than others.  Oak is a prime example of open grain wood.  The shapes I specifically cut for this project were on closed grain (I believe it’s birch ply), but the circles were open grain oak ply.

Like buttercream frosting :)
Like buttercream frosting 🙂
Post filled and sanded disks. They are amazingly smooth!
Post filled and sanded disks. They are amazingly smooth!  The lighter spots are the fill.
Side angle on the sanded disks to better show texture.
Side angle on the sanded disks to better show texture.

Open grain needs to be filled in order to achieve a smooth surface, and that is where the DAP grain filler comes into play.  I purchased it in a tube, and it comes out like a putty almost.  We slathered it on against the grain, making sure it got into the pores of the wood.  Scott said “fill it proud!”  Well, we definitely did – it looked like we frosted cupcakes when we were done.  In retrospect, we make have over filled, and I would probably have thinned the paste a touch with water to make it easier to work with.  Live an learn!  Wait for it to dry (it was thick, so we waited 24 hours) and then sand off the excess.  You sand enough that you want to see the prominent grains, but it will be smooth as glass.

Picking up a closed grained wood allows you to skip this step, which I would recommend unless you wanted to look of oak or a specific open grain wood on the back.

Step 3: Acrylic Gesso Wash

Gesso, for those that do not know, is a priming paint.  There are versions for painting with oil paints and for acrylic paints.  Oil paint *can* go over acrylic gesso, so, for versatility’s sake, we used acrylic gesso.  It is made with white pigment, chalk, an acrylic binder (to make it a liquid) and a smattering of other chemically stable elements.

Why prime your wood with gesso?

  • It creates a uniform,  layer under the paint
  • It gives you surface a nice “tooth” to hold paint
  • It keeps paint from soaking into the material underneath
  • It protects the paint from chemical changes on the board underneath – wood is organic, and the process they use to create plywood is not exactly archival.
It's hard to see in the photo, but the gesso wash is pretty frothy!
It’s hard to see in the photo, but the gesso wash is pretty frothy!
Wiping away the gesso wash
Wiping away the gesso wash

You can slap the gesso on, undiluted, but it really doesn’t penetrate the wood very well.  We mixed up a gesso wash, which is gesso + water.  It may have been a 50/50 ratio, I should have been measuring!  But you want it nice and runny.  We put it on with a foam brush.  You can also use your fingers if you like a more tactile experience.  We really smushed it on, working it into the grain of the wood, which created a sort of foamy looking paint layer.  When we were satisfied with had penetrated well, we wiped off the excess paint with a paper towel.   Let dry thoroughly.

Step 4: Light Sanding

The gesso wash soaked in well, and caused some of the grains of wood to swell, and the dried surface was slightly uneven.  We hit it quick with some 400 sandpaper to smooth it out.  It’s not uncommon for artists to sand between each prep layer – it gives a nice even finished look.

Step 5: Full Strength Gesso

This is the step where the ground work you lay down has a stronger effect on the finished piece.  Scott suggested a couple different ways to incorporate texture with the gesso layer on the laser cut shapes:  with brushes, or with foam rollers.

Swirled whale texture
Swirled whale texture
Flowing bird texture
Flowing bird texture

Full strength gesso has the ability to hold some texture; it’s not self leveling as a more watery version would be.  We took brushes to the whale and the swallow.  I made swirls of gesso on the whale, trying to emulate a turbulent sea.  Scott chose to paint gesso on the bird with long, flowing brush strokes, to evoke the feeling of flight, or airiness.  The subtle peaks and valleys of the gesso will still be present behind whatever paint it will have in the end, adding a depth.

First layer of the foam roller texture
First layer of the foam roller texture

The more geometric shapes for the foam roller treatment.  Rolling on the full strength gesso created a fabulously fine pebble texture, almost like vinyl.  The first layer looks suspiciously like a popcorn ceiling treatment, but it calms down with repeated applications

We let all the pieces dry overnight.

Step 6: Repeat Step 5 as necessary

Everyone has different goals for their primer, and different levels of “done.”  We put a second coat on, and looking as I’m writing this post, I’m tempted to do a third.  As it dried (and sadly got got banged up a bit when I cleared off the table they were on) imperfections became clear – the brush lines weren’t exactly where I wanted them, or had areas where the vinyl-like texture was less pronounced.  If you want, you can also do a quick sanding between each coat of gesso – it’s up to you and the finish you want!

Step 7: Add art!

When you feel your board is primed properly – but that, I mean it has even coverage of gesso, a good texture and reminded me of a sheet of really nice paper that I was itching to put my pencil to – you are ready to add your art.  I didn’t intend for the project to go to the actual art stage, but Scott and I were experimenting, and I couldn’t resist picking up a tube of “sap green” acrylic when buying the gesso (colors are so PRETTY.)  Here are three different paint treatments you can do:

From left to right: Wash, glaze and tint. It's amazing these greens all came from the same tube of acrylic!
From left to right: Wash, glaze and tint. It’s amazing these greens all came from the same tube of acrylic!

Wash – We mixed the acrylic paint with water, which created a very flowing semi-transparent layer of paint.  It was very light in color and was very wet.  If we were using oil based paints, we would have used turpentine to thin it.

Glaze – Glazed are made when a color is added to a “transparent gel medium.”  I’m not 100% sure what the medium is made of, but the color was really vibrant.  Glaze is nice because it is translucent – light can penetrate the layer and make it really pop.

Rolling on the tint.
Rolling on the tint.

Tint – here we mixed white gesso with the acrylic and came up with a lovely minty green.  It is opaque.

The gesso base is also good for charcoal, pencils, pastels, oils, even mixed media or collages.  It’s a good standard base to build on.  Today, most painting is done on canvas, but it actually wasn’t until the 16th and 17th century canvas became popular.  By painting on panels, you are paying homage to an old tradition (even though the panel was cut with new technology!)

This post is in no way comprehensive (even though it is the longest one I’ve ever written!), and it’s one professional’s opinion.  Artists come to develop their own style and preparation methods they like – experiment!  And enjoy!