115: Rounded Edges

One of the first limitations of laser engraving I learned about was the right angle. On most (if not all? let me know!) laser engravers, the laser can only fire in one direction: straight down, perpendicular to the surface plane. This means that you can’t easily get beveled edges, rounded corners, or other nice depth effects you can get using a rotary engraving system like a CNC mill.

There are ways around this limitation, of course: a patron I spoke to at the Aurora Public Library‘s Makerspace suggested rigging smaller pieces of material at their own angles, allowing the laser to fire directly down at a skewed surface, creating the angled edge desired. I considered this process, but it only works if you are cutting a single straight line—any shift in the direction will pull the head out of focus with the section of material you’re cutting.

Focus matters, though, as I found out several months ago while cutting some badges for an event. I accidentally left the laser bed way out of focus when cutting one of these badges, and you can see how the laser didn’t cut through, and instead just created a rounded channel in the surface of the material, in the shape of the badge I’d intended to cut. It made me realize I could cut a shape normally, and then cut it again out of focus, to give the edge a soft curve.

The mistake that taught me how to round corners via unfocused engraving.
The mistake that taught me how to round corners via unfocused engraving.

So this month, I got around to testing that some more! I opted for some snowflake designs (sourced from freepik.com; thank you!) to give me plenty of edges to smooth and for general holiday goodness. The first step is to cut the piece normally, which results in the traditional sharp 90 degree edges you see in most lasered pieces.

Sharp 90 degree edges, standard for laser cutting.
Sharp 90 degree edges, standard for laser cutting.

Leave the leftover material in the laser bed, and do your absolute best not to disrupt its place. In fact, I suggest not touching the piece at all at this point and just telling the laser to fire again with new settings. Specifically, I threw the laser out of focus by telling it I was engraving on a 1.125″ thick material rather than a .125″ thick material. I’ve experimented with different unfocused settings, and can probably dial that in a little better, but 1″ is a nice easy number to get a decently rounded corner on a 2″ lens. I also sped up the laser a little bit because I didn’t want to overpower the edges when rounding them (while my speed settings won’t match yours exactly for a multitude of reasons, I cut the snowflake at 5.5% speed and then rounded the edges at 15% speed.)

The top side is now rounded; it's an imperfect process and looks a little rough up close.
The top side is now rounded; it’s an imperfect process and looks a little rough up close.

Since the rounding only happens on one side, you’ll have to flip the piece and round the edges again if you want to give both surfaces the same treatment. This is only possible if your piece has an axis of symmetry, and this is where you have to be very careful not to move your temporary jig. Once you’re done, you might have to clean the piece as firing a laser out of focus can produce a fair bit more detritus than firing it in focus.

Make sure to clean your honeycomb first, and wipe down any residue between each step. Oh, and use a clean cloth! Trust me!
Make sure to clean your honeycomb first, and wipe down any residue between each step. Oh, and use a clean cloth! Trust me!

As it turns out, even if you don’t move the makeshift jig at all, your second pass might be slightly out of alignment to the first. Why is this? Kerf—the width of the laser—means that your freshly cut snowflake might shift a fraction of a millimeter inside the jig. There’s a tiny, tiny little bit of give and it can sometimes be enough that the alignment is visually off. You can solve this by rounding one side before cutting, but you’ll still have to contend with this on the back half, and kerf didn’t affect my alignment nearly as much as another issue:

Much more alarmingly, I discovered while doing this project that pulling my laser out of focus by about an inch noticeably moves the laser’s aim. It’s not enough to ruin the project, but it is enough that I had to correct for it after several prototypes to get a nice even rounding. This aim issue as the laser focus changes is due to incorrectly calibrated mirrors somewhere along the laser’s path (totally my fault, as I foolishly adjusted them once upon a time and have been tweaking them here and there ever since) so if your mirrors are factory aligned like they should be you shouldn’t run into this issue.

Even if you don't move the piece at all between steps, kerf or poorly calibrated mirrors might cause your rounded edges to be misaligned.
Even if you don’t move the piece at all between steps, kerf or poorly calibrated mirrors might cause your rounded edges to be misaligned.

In the end, the rounded edges are a little rough looking, but if you get your settings dialed in (or would it be dialed out in this case?) you can get a nice smoothed edge that will catch light in a novel way for a laser cut item. I used opaque and translucent acrylic for this project, but I know this effect would look great in transparent and fluorescent acrylic as well. I can’t imagine it working as well with natural materials or microsurfaced plastic, but maybe I should experiment with that in the future!

If you have any unfocused laser tricks, or tips for keeping materials clean while processing pieces in multiple steps, let us know in the comments below! Happy holidays!

114: Enamel Stencils

img_20161023_144721598I’ve always been curious about enameling, but I wasn’t ready to buy lots of equipment for something I wasn’t sure I’d do regularly.  I understood the basics of enameling – powdered glass is fired to its melting point, and it adheres to the metal beneath.  Designs can be drawn on (well, the powder can be moved around at least), or most easily, stenciled.  This was my in; my justification for taking the class. I could use the laser to make my own stencils!  Satisfy my curiosity AND get a blog post!

I’m a fan of Water Street Studios on Facebook, so I am continually tempted by their class offerings.  I signed up for their last “Introduction to torch fired enameling” class of the year, taught by Lisa Dienst-Thomas of Lisa’s Pieces.  Water Street Studios was a real treat – it’s only about 20 minutes away from me, but I’d never checked it out  They offer classes, have artists studios (both 2D and 3D), host lectures and have gallery space.  Creativity is steeped into the place.

Lisa was a great instructor and I had the pleasure of being the only student in class (which means I got to ask a lot of questions!)  She provided all the materials and had everything neatly laid out.

Starting tools, from left to right: Spatula, plastic container (just to keep spatula level), tweezers, fine tipped brush, awl, small sifter, large sifter, toothbrush, foam backed sanding block
Starting tools, from left to right: Spatula, plastic container (just to keep spatula level), tweezers, fine tipped brush, awl, small sifter, large sifter, toothbrush, foam backed sanding block, and old magazine pages in the upper right

The Tools:

Spatula – you use this transport your piece flat from the table to firing stand.  This is important because the enamel is a dry powder sitting on top.  Tip it and it the powder will fall off.  And you can’t touch the top with your fingers, lest you deposit oils on the surface and cause the enamel not to stick.

Little container – that’s just to hold the spatula level – the bent handle causes it to tip.

Tweezers – so you can move your fired piece without touching the top, saving it from the dreaded finger oils

Brush – moves and sweeps away grains of enamel that aren’t exactly where you want them

Awl – a nice sharp point is great for drawing in the powdered enamel

Small sifter – sifts powder over a smaller area, great if you only want to hit part of your piece

Large sifter – covers a larger area

Toothbrush – for cleaning the surface of your piece.  We used pumice-type cleanser, Bon Ami

Sanding block – to clean off the back for the discoloration from firing

Magazine pages – a slick disposable surface so you can save as much of the enamel power as possible, without mixing the colors.  If the colors mix in the jar, there is no separating that.

Not pictured: The enamels.  We were using Thompson brand enamels, Medium Temperature and Medium Expansion.  Also not pictured is the firing stand, mesh and torch.

Piece #1

Stencil 1 - I was kind of going for the Japanese fan motif, abstractly. I wasn't sure if the points would come though well becuase I wasn't sure the amount of detail I'd get with dry powder
Stencil 1 – I was kind of going for the Japanese fan motif, abstractly. I wasn’t sure if the points would come though well because I wasn’t sure the amount of detail I’d get with dry powder

For my first stencil, I created a basic repeating stencil with Japanese fans in mind.  I wasn’t sure how much fine detail would translate with dry sifting, so I was taking a little risk with the small points at the narrow end of the fan.  But that’s what experimentation is about, right?

I made the stencils out of the same material we used for the Pyramid Holograms for Week 100 – 1/32″ think acrylic.  Lisa pointed out some potential difficulties in using thicker stencils – you can inadvertently put too much enamel powder because the spaces are so much deeper.  Also, it might be more difficult to grasp when you are trying to lift it up smoothly.  Lisa likes using manila folders – lightweight, easily obtainable, and you can fold up the edge if you need a spot to grab and lift.

Base layer of enamel - we did two light layers of the same color, to make sure it was fully and evenly covered
Base layer of enamel – we did two light layers of the same color, to make sure it was fully and evenly covered.  You can see how important the magazine page is to not waste enamel!

After cleaning the piece thoroughly with Bon Ami, I sifted a layer of cream colored enamel on the copper base, which made the first of two base coats.  One coat might be a little uneven, a second evens things out.  Tip from Lisa: start be sifting around the edges, then work your way to the center.  Of course, the pieces I was working on were pretty darned small, so it was easy to get full coverage.  Between each layer, we melted the enamel powder with a MAP torch.  You heat the piece from below, which is why you can see my piece is on a 9″ tall firing ring.  It was neat watching it go though sugar stage, orange peel stage to fully fused glass, and it didn’t take as long as I thought it would

Just a little glimpse of the Water Street Studio's jewelry maker space. Note on my shirt: I was a little surprised to look in my closet and only have ONE long sleeved cotton shirt. Since I knew I was working with fire, I didn't want and potential issues for man made materials.
Just a little glimpse of the Water Street Studio’s jewelry maker space and the torch set up. Note on my shirt: I was a little surprised to look in my closet and only have ONE long sleeved cotton shirt. Since I knew I was working with fire, I didn’t want any potential issues for man made materials.  Photo by Lisa Dienst-Thomas.
Tapping the cute little sifter allows for even application of the powder on the stencil.
Tapping the cute little sifter allows for even application of the powder on the stencil.
Powered stencil pattern, before firing
Powered stencil pattern, before firing

After the piece was cooled and cleaned, it was time for the third layer. I lined up my stencil and sifted a very light layer of enamel on it.  There were some errant grains that I used the fine brush to get rid of.  One more firing, some clean up to the back and sides with sandpaper and add a bail, we’ve got a finished piece!  Easy, right? 🙂

dsc01105

Piece #2

Lining up the stencil
Lining up the stencil
Powdered stencil
Powdered stencil
The stencil came off surprisingly cleanly - I didn't have any clean up work! I thought I was homefree!
The stencil came off surprisingly cleanly – I didn’t have any clean up work! I thought I was home free!

My second piece pointed out my hubris.  I followed the same process  – two base coats, a layer for the blue bunting and this one included a fourth layer of Orchid pink.  There was very minimal overlap with the blue bunting strand, so I didn’t think the 4th level would be a problem.  I was wrong.  Things this piece taught me:

  1. Light colors should go on first, dark after. I intended the pink to be the top layer, but where it over lapped, the blue still comes through.
  2. Really, there should be only 3 layers on powder on the piece.  There is a little wiggle room based on the thickness of the powder you lay on, but as a beginner, I was a little heavy handed.  The more layers, the harder it is to heat and fully fuse.
  3. Enameling is really just glass on metal.  If it is improperly cooled, not fully fused or even dropped on a hard surface, the colors can crack and flake off.  I didn’t apply enough heat where the colors overlapped, and there was a huge crack.
  4. You can reheat pieces, in the hopes to fully fuse them.  We did that….and then had did it again because the second final torch firing didn’t take care of the crack fully.  It took three tries to fully fuse this piece!  Between chatting and refiring, I kept Lisa 2 hours late!  Thankfully, she was as committed to getting it right as I was.
  5. Reds and pinks are temperamental souls.  The orchid pink enamel DID NOT enjoy being reheated, twice.  It separated interestingly, and allowed the base coat to come through.  So instead of two solid bunting lines, I have a love blue on and a lovely pink crackly / shabby chic one.
    If you look closely where the bunting crosses, there is a crack. THis means that the glass didn't fully fuse to the copper beneath - which meant it will pop off eventually.
    After the first final firing.  If you look closely where the bunting crosses, there is a crack. This means that the glass didn’t fully fuse to the copper beneath – which meant it will pop off eventually.  The pink looks pretty good at this stage!

    The final piece. The crackling is actually interesting to look at, but I think it would work better with a more abstract piece.
    The final piece. The crackling is actually interesting to look at, but I think it would work better with a more abstract piece.  Sadly, I didn’t use the cute arrow I designed.

In total: Enameling was a lot of fun.  The tools are actually relatively minimal – I actually have nearly everything from my jewelry making forays except the actual enamels and the firing stand.  I know I’ve only scratched the surface on techniques, but I love that I can use the laser to make a more unique look that using store bought punches for templates.  Maybe Lisa will teach Enameling II in the future 🙂

Finished pieces. Do the crackles on the bunting make it shabby chic? :)

113: Mother of Pearl Veneer

The inspiration for this week’s post is Carry A. Nation, the famous barroom smasher.   Carry believed that alcohol was the root of all society’s evils, and she  took hatchet to things she didn’t like (namely bars, whisky bottles and paintings of scantily clad ladies).  Though some called her mad, her barroom appearances had the strange effect of *increasing* business for tavern owners, so much so they often invited her to smash up the joint.  Carry didn’t mind, as her message was still being heard.  She was also a shrewd marketer, and sold merchandise to support her cause.  She lived comfortably and even ran a home for women and children whose lives had been effected by alcohol.

Given that I’m actually enjoying a Not Your Father’s Root Beer while writing this post, you can assume I will not be taking up the cause of temperance.  The museum I work for is doing a fabulous fundraiser set in a 1910s saloon, which will feature none other than Carry Nation, as portrayed by my mentor Ellie Carlson of Ellie Presents.   (Happily, our event is sold out, otherwise I’d be selling you tickets too.)  Ellie owns an original Carry Nation hatchet pin, and was commenting that she couldn’t get anything like it to sell in character.  Cue the laser.

Original Carry A Nation pin, as worn by Ellie Carlson
Original Carry A Nation pin, as worn by Ellie Carlson

Ellie’s pin is a brass hatchet that features a mother of pearl head, which cleverly stops just short of the edge of the brass to make it look like it has a wicked sharp blade.  Brushed gold make a nice substitute for the brass, and I finally got to experiment with mother of pearl veneer.

We first played around with mother of pearl in the laser when we tested engraving on different bead materials back in Week 32.  The beads turned out beautifully (if a little sooty.  But that just made the engraving stand out better.)

Shell beads, vector on the left, raster on the right
Shell beads, vector on the left, raster on the right from Week 32

dsc01005Because our event was coming up in short order, I ordered a “pressure sensitive” (aka peel and stick) sheet of mother of pearl veneer off Amazon.  at $25 for a 9×6 inch sheet, it’s not cheap, and I should ave read the reviews better.  The reviews were poor for this seller, and upon opening the package, I found my sheet had the same issues.  Oops.  The iridescence, created by the nacre on the inside of the shell, was inconsistent.  The package was flimsy, just a soft box and a sheet of styrofoam, so the surface was a spider web of cracks.  Lesson learned – find a reputable seller.  Timing and budget didn’t allow for a second sheet to be purchased.

Disappointing
Disappointing
Cutting was a breeze
Cutting was a breeze

The hatchets were small enough, I figured I could find a good spot on the sheet to cut them out.  I went with a full hatchet head design rather than the one with the short back, like Ellie’s pin, mostly for ease in aligning the mother of pearl to the base.  Carry Nation herself had a lot of different styles of pins, so I figured I could take the liberties.  For laser settings, we gave it a little more power than card stock.  It sliced through quickly and easily, though the edges were a little sooty, like the beads.  Not unexpected for organic materials.  (I later learned that when cutting mother of pearl with a knife you should cut from back to front.  It’s a very brittle material – I’m not sure if it would have made a difference on the laser, though.)

The backing came off surprisingly easy
The backing came off surprisingly easy.  I was expecting it to be a little difficult, especially with the cracking on the veneer, the but the sheets held together surprisingly well.
Incredibly translucent
Incredibly translucent

After I peeled the backing off the cut veneer, I had another disappointment.  I didn’t expect the mother of pearl to be so sheer!  I could read through it.  I expected more body, so it would standout from the brushed gold acrylic.  Honestly, it was difficult to even see it was there at a glace.    As a test, I cut out a silver version of the ax.  The veneer stood out slightly better on it, but not enough to make a difference.

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This photo was taken at the perfect angle to catch the iridescence. It looks better in photos.
The flaws are still kind of noticeable on the finished piece.
The flaws are still kind of noticeable on the finished piece.

In the end, Ellie and I decided it was better to do the pins without the mother of pearl.  This of course, isn’t a radical departure from Carry Nation herself – she sold a cheaper version of the pin without the mother of pearl as well.   I want to try using the mother of pearl again, perhaps on earrings or accents, where the perfection of the sheet doesn’t matter as much.  But I’m not sure it’s something I would order again.

Because I couldn't resist, I also made up a pin based on this much larger cast iron piece. The laser's half toning capabilities made transferring the image of Mrs Nation's face a breeze!
Because I couldn’t resist, I also made up a pin based on this much larger cast iron piece. The laser’s half toning capabilities (more visible on the left) made transferring the image of Mrs Nation’s face a breeze!

112: Three-Ply Acrylic

It’s kind of amazing that it’s taken me this long to get to this project; when 52 Lasers was first conceived, using three-ply acrylic was on the first draft of our potential projects list. Now, more than two and a half years later, I finally have a project that requires this unique material!

Rowmark's convenient visual representation.
Rowmark’s convenient visual representation.

Three-ply acrylic is similar to the two-ply acrylic I use very often, except the thin cap layer is applied to both sides of the main acrylic substrate. While most of the badges, magnets, and other pieces I make only need one side to be engraved, certain items like medallions or coins might need both sides engraved, and this is when you’d use a three-ply option. This month’s project is a great example.

 

A bunch of SCA tokens celebrating an elevation.
A bunch of SCA tokens celebrating an elevation.

A couple of dear friends of ours are part of a group called the Society for Creative Anachronism. While I’d like to explain what that is for you, I couldn’t possibly do better than the SCA’s excellent portal for curious newcomers. Dave got in touch and explained that his husband Jim was going to be recognized for his accomplishments in the Society, in a ceremony called an elevation. For the event, they wanted to distribute small tokens, in SCA appropriate colors, featuring Jim’s moniker in Chinese (凱曾, Kai Tseng) and the triple rapier logo of the Order of the Masters of Defense. I’ve always used wood for tokens that need both sides engraved up to this point, but it was far easier to get the colors Dave and Jim wanted by using the three-ply LaserMax acrylic from Rowmark.

When you’re engraving two-ply material, you don’t really have to worry too much about the back face; people aren’t going to be scrutinizing a blank back surface, so imperfections caused by the manufacturing process aren’t a big deal. That’s why two-ply materials only ship with mask on the front surface. Three-ply material has mask on both cap layers, and while you want to remove the mask from the side you’re engraving first, you definitely want to leave the mask on the bottom side. That’s because those vector cutting scars—plastic residue, honeycomb table impressions—are going to damage that side if you don’t. It’s okay to engrave the reverse side with the original side unmasked because you won’t be doing any high power vector cutting in that final step; it’s just surface engraving, which doesn’t cause those kinds of issues.

Red tokens placed upside down in the makeshift jig.
Red tokens placed upside down in the makeshift jig.

Conveniently enough, just cutting the shapes out in the first pass automatically creates a makeshift jig—or template—out of the leftover material. As long as you send the second half of the engraving data in the same exact positions as the first, all you have to do is flip the shape over and engrave again. Now, this requires a symmetrical shape, or else you’ll have to take flipping into consideration and cut extra pieces out of the material that will form the jig. You also want to remember to take the mask off of the flipped token’s new front side before engraving; firing the laser through that thin plastic layer will usually create a sticky mess.

With all of that in mind, it’s fairly simple to process three-ply material in a clean manner. You’ll still have to wipe down the edges with a light alcohol or a solvent similar to Goo Gone, but that’s usually the case with two-or-more-ply acrylics anyway. For how simple the whole process is, I still managed to muck things up, and I lost a whole set of twenty yellow tokens on the first pass due to a technical issue with the laser that I still haven’t figured out.

Unexpected markings ruined a whole batch of tokens.
Unexpected markings ruined a whole batch of tokens.

Once in a while, when raster engraving, the field I’m engraving will be speckled with tiny additional engraved dots. I can never predict when it happens, and just rebooting the system fixes it, but it always loses me a piece or two.

Token stacks.
Token stacks.

I also noticed with this project that my laser alignment isn’t perfectly perpendicular to the engraving surface currently; if you look a the picture of the token stacks above, you’ll notice the slight skew in the 1/8″ thickness of the tokens. I think this is due to a misaligned mirror #3, but it’s difficult to know for sure and I might end up having to replace the mirror #3 assembly with a factory-calibrated one.

If any of you have any tips for cleaning the laser-cut edges of a two-or-three-ply piece, any ideas on what might cause the rare engraving field speckling, or any suggestions on how to realign the beam path across the surface, let me know in the comments below!

One laser, fifty-two weeks