Introduction: TechShop RDU-Laser Engraved Aromatic Cedar Side Table
The following Instructable is of an aromatic cedar table with a laser mandala engraving. I made it at the TechShop-RDU Facility a long time ago and just forgot it in the "incomplete drafts" section, so I thought I'd polish it off for your approval. Enjoy...
The image I ultimately used was from the website of artist Kathy Ahrens. Look at her stuff here:
Step 1: Initial Milling
The first picture here is just of the boards directly from the mill distributer (Capital City Lumber in Raleigh, NC). Aromatic cedar (which is technically a juniper I believe) has a beautiful contrast & grain pattern, works incredibly easily, is bug/rot resistant, and gives off one of the best aromas on earth. If you haven't worked with any yet, go to your local mill and try to get your hands on some (the major retailers tend to be too expensive).
I measured out 24" lenth (maximum capacity width for the Epilog Helix 60 watt laser engraver TechShop RDU has) and cut several board lengths that I thought would be a good match. An aesthetic note, if you get a fully red board in the center, and get the outer white wood of the other two on the outside, you get the effect of a single slab of wood, which gives an added touch.
Once one end was mitered flat, I clamped the boards together for a more exact cut and took off the opposing end. The closer to even length you can get them now, the less you have to worry about them later.
Step 2: Joiner & Cutting Biscuit Holes
I forgot to add pictures of the process here, but this is just prior to using the joiner. The joiner functions by creating what is essentially a perfectly square face in relation to the face pressed against the back plate. Done properly, the pieces go from being oddly spaced to perfectly flush along the complete length, which you'll need for the following steps.
Next, I place the pieces down on a flat table, and decide what their final orientation will be. I draw out 5 small marks, starting at the center and spaced every few inches. These will be for your biscuits. Make sure you do overlapping lines to reference later. For example, at the intersection of board 1 & 2, draw your five notches partly on board one and partly on board two. That way, you'll have an exact point you want to hit for perfect fit biscuits. Here I'm using # 20's but # 10's will work fine if done properly. The last picture shows a view of the completed slots. (NOTE: Make sure you move the boards one at a time, since confusing their orientation right now could ruin the project, or at least seriously derail it. The pencil marks you made will help you determine which side is up vs. down as well as where the top or bottom of the boards are. Just take it one at a time and be mindful of what you're doing)
Step 3: Dry Fit & Glue-Up
Be sure to dry fit your joints w/ biscuits before you apply any glue so you don't get rushed later on by any oversights. I apply glue on one side (being sure to get some into the biscuit holes), butt in the joints, and then apply to the other. Go ahead and get the whole table top glued up now. A small mallet helps you center any boards that slide to the side a bit. The pencil marks come in handy here, since the two halves line up perfectly when they're even. Clamp the boards in several locations, and apply a decent amount of pressure. If you squeeze too tighlty, the boards may bow up, but this can be mitigated by either loosening a bit, or placing cross clamps to hold the pieces flush to the table.
Step 4: Over to the Laser Folks
After allowing to dry for around an hour, I unclampled the pieces and took them to a sanding table, where I used a random orbital sander (first 60 grit, then 80, then 120 & finally 220 by hand) to even out the edges, surface differentiations between the boards, and any defects. Get it as close to finish ready as you can at this point, since any extensive sanding after the laser process will be difficult and could take small pieces off of the design. I used CorelDraw 6, and pulled an image off of the internet.
I searched Google under "Mandala Drawing" with a filter for over 2MP. This is the first (and by far the best) one I found. An artist by the name of Kathy Ahrens made it. Her website link from the search is: http://kathyahrens.deviantart.com/art/Goliath-the-Intense-Beautiful-Mandala-Drawing-309712769 Yes, the piece is called Goliath the Intense Beautiful Mandala Drawing. Makes sense. Check out her page, it's got all sorts of really elegant drawings and art on it. (Well wishes to your son on the Enterprise Mrs. Ahrens)
This a rastor image, with Speed set at 90% & Power at 100% (600 DPI). You can see the laser doing it's work in some of these pictures, and the piece starting to emerge.
Step 5: Inspectah Deck
Here is the table top directly after the Epilog Helix. Because of the depth and color of the etching, as well as the contrast colors of the cedar, I'm not going to stain it. I'll add 2-3 coats of polyurethane (Rust-Oleum has worked pretty well with me) with either a synthetic brush or a compressed air spray gun. Take a little time when it comes off the laser to smell the difference between the ambiant and the burned wood. Cinnamon?
Step 6: Apply Poly/Shellac/etc. of Your Choice
You can see the intricracy of the design at work here. The image is rastored about 1/32 of an inch deep, so it produces an acute physical texture. Next I applied a coat of poly, but rushed it and didn't tack cloth the image properly first, so there were a lot of dust particles and bubbles in it. Not too big a deal, since I sanded it back down anyway, and this helped even out the pores.
Step 7: Cutting Legs
Since I've been considering selling some of these tables with original images, I've been looking for a way to produce legs that are stable, elegant, and repeatable. This is what I have so far, but I'll include any improvements at the end. First I glued two planed boards together, clamped them, and then put them on a joiner and miter saw so they were even and square all the way around.
Step 8: Cut and Taper Legs
Then, I placed them on a leg taper jig I made and clamped them with toggle clamps (these little things cost about $10 a piece, latch shut with no effort, and exert about 500 lbs. of pressure each when used properly). I'll do a follow up instructable on how to make the leg taper jig when I decide to make one that looks better and isn't falling apart like this one.
Run the leg through the saw, turn it, adjust the clamp closest to the saw down a bit, and run it again. This will give you a leg that is tapered on two sides (the two sides that will eventually run on the inside), and adds a bit of elegance while maintaining structural integrity. I used hickory because I had some laying around, but on future runs I'm going to use the same aromatic cedar to maintain some consistency. Still, the contrast should be nice.
Then, I flipped the table and placed markings for where each individual leg was going to go.
Step 9: Leg Attachments
I took a 1 1/2 inch forstner bit to the drill press at TechShop and set a depth to a little less than halfway through the board centered on my markings. Using a 1 1/2 chisel (with a smaller one for detail) I cleaned up the edges. The rastoring you see in the last picture is from the first time I tried to laser. For some reason the image stopped halfway and started repeating off center at the top, but since it will end up on the bottom I kept the board. The next step is to dry fit the legs.
I decided later that a better thing for the legs would be to take them to the lathe before I taper them, turn the last 1/2 inch of one end down to 1 or 1 1/2 inches, and then just have them fit snugly and evenly into the board without having to chisel. Next time, maybe. This process works fine, but the fit with glue isn't snug enough, so what I think I'll do is glue up the bottom, screw it in from the top, and then add a dowel piece on top to cover up the screw. It might add some character to the table, but the added effort isn't worth it, and I would prefer that it be cleaner. Lesson learned.
Step 10: Final Thoughts...
This was a project from a while ago, so I was partly learning on the job. The top turned out beautifully, the aromatic cedar darkens as it ages and gains an elegant patina. The one change I would have made would be to the legs (sorry, no side shots of the table). That tapered variety is much better for a thicker table, and in the future I'd use something with contrast instead of going for the same material, maybe some modernist metallic legs.
All in all, this was a fun build. I found this project in my "drafts" box and thought it'd be a shame not to complete and publish. TechShop, where this was all done, has closed down unfortunately.
I'm open to all advice and constructive criticism. Let me know what you think.
Thanks folks, take care and enjoy the build...
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