Introduction: Sculpted Procedurally-generated Shelves
I'm an artist interested in procedural/generative design. I love looking for inspiration in nature (and there's plenty of it!) and attempting to mimic or augment that just to see if it'll look cool. In my previous job that passion stayed in the digital domain, working on award-winning animated movies and focusing on everything from flowing sand to swaying trees to current-swept seagrass.
Lately I've been yearning to translate this into the physical realm, and being a little experienced with wood, things are finally starting to take shape.
This instuctable shows how to make very sculpted, organic-looking shelves using stacked-lamination techniques and lots of power carving. The shelves' shape is computer modeled using 3D software based on a few math functions, though you can start with whatever shape you like, whether computer generated or hand-drawn.
I used white oak for those shelves. I love how big its pores are and how textured it is to the touch. It's also not as commonly used as its cousin red oak which makes it a little more unique.
Note: If you're hand drawing your design, feel free to skip STEP 2: Modeling and move on to STEP 3: Creating templates.
Step 1: Modeling
I modeled the shelves using Houdini, a 3D package made by SideFX software. As I mentioned before, any approach should be good for this, and it really depends on what you're comfortable with. Rhino, Maya, 3D studio max, etc. should all work. Even SketchUp should work, though it's less intuitive at generating organic forms. I'll describe my approach here.
I started with a simple box of the right dimensions and then created some hand-defined curves to control the general shape (shown at the right side of the screen). This allowed me to taper the ends off and also have more coarse control over the shape of things where I needed it. For example, the wide shelf shown is meant to go over the kitchen sink so I created a narrower area so I could wash dishes more comfortably
For some more visual appeal, I then perturbed the point positions using noise, opting for low frequency along the width of the shelves as opposed to high frequency along the height of the shelves, which made for some visually interesting features. The second and third photos show some details without, then with, the added noise.
One thing I didn't take into consideration was the actual way I was going to mount the shelves to the wall. I ended up using z-clips, which are akin to a French-cleat system made with aluminum extrusions. There's a minimum height required before they with show at the back of the shelves, and looking back, I probably should've modeled the shelved a little "thicker" where they meet the wall so that the hardware was completely invisible.
Step 2: Creating Templates
As the name implies, stacked lamination involves two or more layers stacked (and glued) on top of each other to create a large, usually quite sculpted shape. For example, to make a tree trunk, you can stack lots of slightly different discs decreasing in size as you go higher. Each shape is not too complicated, but the end result can be quite sophisticated and visually appealing. The shapes are exactly as if you had chopped up the tree every inch or two across the trunk then restacked them on top of each other.
To follow the same approach, I needed to "chop up" my model to create templates for each layer. There's a tradeoff in this: The thicker the layers, the less glue-ups I'd need to go, but the more expensive the wood and the lower fidelity (coarser) I'd get to the original shape. The thinner, the more accurate the shape but also the more effort in milling and gluing each layer.
I settled on about 5/8th of an inch for the layer thickness. This meant about 6 layers in total which was very manageable and a good trade-off thickness.
I was able to get Houdini to create each individual layer with boolean operators. You can see a snapshot of this in action. This will probably work in most 3D packages. Other software like Autodesk's 123D Make has this feature built-in.
My transition from the digital realm to the real world involved rendering each layer with a top-down orthographic camera at a high resolution and printing the results on A3+ paper. I could then stick the paper to the wood layers and use them as a guide to cut the coarse shapes of each layer.
NOTE: If you're skipping the whole 3D design side of things, you can simply sketch the shape of each layer directly on the wood and follow along on the bandsaw. Try to get some continuity in each layer so things flow nicely and you don't end up with very sharp curves along the height.
Step 3: Cutting Layers and Glue-up
This step is fairly straightforward. Starting with the top layer, I cut the layers on the bandsaw, following the outlines of the printed shapes. After each layer was cut, I could glue it to the previous layer and while that was drying, I could work on the next layer. This meant that the shelves were built upside down, which explains why you only see the sculpted bottom in most the of photos. The flat top is on the bottom. Make sure you have lots of clamps!
After the glue-up was finished, I used a jointer to even out the back of the shelves, ensuring they mounted flush against the wall with the shelf tops being perpendicular to the wall.
Step 4: Installing Mounting Hardware
Now that the glue-up is done, it's a great idea to do any other operations that require serious clamping since it's much harder to secure the shelves after they've been carved.
As mentioned before, I used z-clips to mount the shelves. When installed, two z-clip extrusions are exactly 1/4 inch, so I routed out a 1/4 inch insert for each mounting point. I placed those 16 inches apart, so they could be mounted securely to the wooden studs in the wall.
The website I thought was the most comprehensive with selection was:
Some of those are available on amazon as well:
Note that the rails I bought didn't have holes punched in them, whereas pre-cut clips usually do. I'd check with them if that's a concern. It was easy enough to do it at the shop.
Finally, here's a good video for using them and planning for them (I think those are the heavy-duty versions). They show up 50 seconds into the video:
Step 5: Carving
Now that the glue has set, it's time to do some serious carving. This is a lot of fun but can be tedious in the beginning to remove the bulk of the wood and get close to the final surface. You can definitely use a CNC wood router for this, but I think it takes away from the creative (and meditative) process of free hand sculpting.
After looking around at some carving and sculpting tutorials (some links are at the bottom of this page), I decided to go for a couple of sanding discs that are mounted on an angle grinder. Those are carbide-coated and are in my experience quite safe and predictable to use. I expected to need a lot of clamping but the sanding discs were so good at removing material that they barely moved the shelves at all. That being said, the smallest shelf I made was 4 ft wide so if you're doing anything smaller, consider clamping, at least in the beginning, and see how things feel.
I ended up using a "Very coarse" and a "Coarse" combination of original coating sanding discs from Kutzall. In retrospect, things would've gone a lot faster if I chose an even more aggressive dish wheel to move the bulk of material and then switched to a finer disc for sculpting the final shape. That would've cut down my sanding time as well.
The different layer profiles helped to guide the sculpting a lot. Another thing I did to stay true to the original shape was to print side sections of each shelf at regular intervals and use those to see how close I was to the original shape. You can see those laid out under the smaller shelf, complete with their distance from one end. I ended up not following those too closely as it was just fun to look at where I was every once in a while and then decide how I wanted things to look next.
I found that carving in long broad strokes helped get very fair curves without too many hills and valleys. It took me a couple of hours before I was comfortable enough to make deeper cuts. At first I just kept removing material until I got close to completely removing those "steps" between each layer of wood. Once I was close enough, I went a little slower and switched to the finer of the two discs I had. This was key as it left a much smoother surface and made sanding much more manageable.
For the smaller details I switched to a round-nose burr mounted on an air-grinder, and for even more delicate features I used different sized round rasps. This was a lot of fun and it felt great running my fingers on the final surface, looking for any small spots that needed evening out.
A couple of useful carving links. A big shout-out to Paul from Canadian Woodworks for the helpful tips:
And the disc manufacturer:
Step 6: Sanding (and Sanding... and Sanding...)
I started sanding with 60 grit sand paper, but soon realized I needed to start with 40 grit if I wanted things to move along. I used a hard pad for the shelf tops to keep the surface flat, and switched to a soft pad for the sculpted bottom. This enabled me to get to the harder to reach, concave areas in the surface.
As I mentioned in the previous section, I should've probably opted for an even finer sanding disc as a final carving step. This is basic wisdom that I keep re-learning: If there is something you can do accurately (and safely) earlier with a faster, more potent machine or process, rather than later with a less aggressive and slower finer process, always choose the former. In this case, opting for a finer sanding disc on the angle grinder would've saved me a lot of time sanding.
A brief way to say this: Don't skip grits, or sanding discs, for that matter.
On with the sanding. Starting with 40 grit, I then moved on to 60, then 80, 120, and finally 180 grit sandpaper. I usually don't go higher than that for white oak as I feel a satin, more muted finish with plenty of texture is truer to the white oak's nature.
I used a random orbit sander throughout. Mine has integrated dust extraction and it makes for a very clean environment. I usually wipe any left-over dust between grits, and wipe some mineral spirits with a rag every once in a while to spot any spots I missed or that need more attention. This is perhaps the most important step in sanding as it catches any sanding defects and allows me to fix them before applying any finish. The fewer the surprises, the happier the woodworker, right?
My design had relatively sharp edges where the flat top met the curved bottom. As I was sanding, I realized that I was making those a little too sharp for my liking. I did a final pass at sanding the edges right to dull things a bit.
Step 7: Finishing
Almost there! Like the choice of wood, this is totally up to you. The best finish is probably the one you're most familiar and comfortable with.
I used a wipe on varnish (Arm-R-Seal by General Finishes). I like it because it's really hard to mess up and I just apply it with a rag. There are plenty of tutorials on YouTube for this.
I usually apply 4 coats, and each application looks like this:
- Wipe the surface lightly with mineral spirits to pick up any dust.
- Apply a coat of wipe on varnish, going from a heavy coat in the beginning to a very light coat at the end. It takes about 4 hours for the first (and heaviest) coat to dry, whereas the last coat probably dries in under 30 minutes.
- Before applying a new coat, lightly sand the surface by hand with 600-800 grit sandpaper. This is to remove any dust nibs that may have stuck to the surface while the varnish was still wet.
After the final coat, I waited for a few days for the finish to completely cure, then I went over it one last time with 1000 grit sandpaper to remove any remaining nibs. There shouldn't be much at all since the last coat dries so quickly barely anything sticks to it.
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