My client came to me with a pretty clear vision: they wanted a custom fireplace mantel that looked smooth, aerodynamic, almost cloud-like. No sharp edges, no traditional profile. Just this organic, flowing shape that sort of floats above the firebox. I loved the challenge, so here’s how I pulled it off.
Starting with Thick Stock
The finished mantel needed to be about 8 inches tall, so right away I knew I was going to have to laminate layers to build up that thickness. I grabbed some 12-quarter lumber — basically 3-inch thick slabs, and started milling them down into usable beams, each one about 6 feet long.
I’ll be honest: these things were a workout. Milling stock this heavy is just a grind, and every step of the process reminded me of that. To get a clean reference edge on each board, I started at the jointer, then moved over to the table saw to rip them to width. Normally, I might reach for the band saw for something that isn’t fully flat on the bottom yet, since there’s less kickback risk. However, the idea of wrestling a 3-inch beam across the tiny band saw table sounded like a great way to throw out my back. The table saw it was. Once I had my widths, I ran everything back and forth between the jointer and the planer to get a flat bottom and a parallel top, which is really just a fancy way of saying I did a whole lot of heavy lifting.
Matching the Grain on the Edges
On a typical tabletop glue-up, you’re thinking about how the grain matches across the face. This project was different. Since the visible part of the mantel is the front face, and I was building up in layers, I needed to match the grain on the edges of each board. The part that would show. I spent some time laying the boards out and rotating them until the grain flow looked consistent from layer to layer. It’s a small thing, but it makes a big difference once everything is glued up. This attention to detail is not something you can get at the Denver Design Center.
Plotting the Taper
Here’s where things got interesting. This mantel tapers in two directions at once. It’s at its full depth in the center, and it gets shallower as you move toward either end. It also tapers from top to bottom, being fuller at the top and closer to the wall at the bottom. That’s a compound taper, and to keep it consistent, I made a series of templates.
My laser cutter wasn’t wide enough to cut the templates at full size, so I made them in two halves and joined them with a little dovetail joint. Once glued up, each template represented a cross-section of the mantel at a specific point along its length — and each one was slightly smaller than the last as you moved down toward the bottom.
Routing Each Layer to Shape
To cut the taper into each layer, I put a collar on my router and used it to trace the templates. Normally, I’d hog out most of the waste on the band saw first, but again, those beams were heavy, and I didn’t want to fight them across a smaller table. So I just took my time with the router and made multiple passes until I got down to the template line. Because the bit wasn’t long enough to go all the way through in one shot, I flipped each piece over, repositioned the template, and cut from both sides to meet in the middle.
Each layer got progressively narrower as it moved toward the bottom of the mantel. Once they were all shaped, it was time to start stacking.
Gluing It Up in Stages
I didn’t try to glue all the layers at once. That’s a recipe for chaos. Instead, I let each layer cure fully before adding the next one. To keep everything aligned during assembly, I ran a row of floating tenons across the back of each joint. That way, when I was juggling all those clamps, the pieces couldn’t slip around on me.
Once the glue was spread, I put what felt like a bazillion clamps across the front edge to make sure there were no gaps where it mattered most. There was a little variation along the back after everything was together, so I cleaned that up with a few passes on the jointer.
Roughing In the Cloud Shape
Before I glued on the bottom layer, I wanted to get a head start on the shaping. I put a large roundover bit in the router table and ran a nice, gentle curve along the front edges of the assembly. That gave me a soft starting point to blend from once I got into the carving — much easier than attacking a totally square corner with a power carver.
After the bottom layer was glued on, I rounded over the top as well. To avoid a dangerous blowout on the end grain, I clamped a block of wood at the start of the cut so I’d have a solid lead-in. I took several passes to sneak up on the full depth, then removed the block on the final pass so I could run the whole length in one clean sweep.
Power Carving the Shape
This is the part of the project I was most excited about, and the most time-consuming. With the blank fully glued up, I started knocking off the high spots and sharp corners with a power carver, working my way around the whole piece gradually.
To stay on track, I used my cross-section templates as guides. Each one slips over the mantel at a specific distance from the end, and since the shape tapers, each template sits a little further down as you move inward. My process was to carve one section down until a given template fit snugly where it belonged, then move to the next template and do the same. Once I had two neighboring templates fitting well, I’d carve the area between them to connect the curves smoothly.
It’s a slow, methodical way to work — but without a CNC large enough to handle a piece this size, it’s the right approach. You’re basically connecting the dots, one section at a time.
Dialing In the Final Shape
When I was getting close to the final shape, I made a couple of sanding blocks out of poplar by pressing them against the mantel and carving a negative of the profile right into the face of each block. Then I glued some aggressive 60-grit sandpaper onto those faces. That gave me a custom sanding block that matched the curve of the mantel, which made it a lot easier to refine things consistently.
To find the low spots and high spots that are hard to see visually, I coated the whole front face with chalk. As I sanded, the chalk wore off the high points first, leaving it behind in any dips or divots. Once all the chalk was gone, I knew the surface was even. I worked through this process a few times, switching to a soft, flexible sanding pad toward the end so it could conform to the organic shape without flattening out the curves.
Prepping for Installation
Once the shaping was done, I centered up a drilling jig and bored holes for the mounting hardware. The hardware was already installed on the job site, so I needed the hole spacing to match exactly. I used an auger bit sized to match the inside diameter of the mounting pipes. The bit wasn’t quite long enough to reach full depth in one go, so I got the holes started straight and square with the jig, then came back and finished them to depth freehand.
To make installation easier, this thing is heavy, and lining up multiple pegs with multiple holes while holding a large beam against a wall is not fun — I eased the opening of each hole with a slight roundover so the pegs would self-guide as the mantel was pressed into place.
Lightening the Load
Since I had to ship this three states away, I also needed to cut the weight down a bit. I built a simple jig and used it to route out a series of evenly spaced slots on the back face of the mantel, removing material in a way that was uniform on both sides. Uniformity matters here for two reasons: you don’t want one half heavier than the other (that creates uneven stress and can encourage warping), and you want it to look like intentional work when the client sees it, not like you were just randomly hacking away at it.
I also routed a metal C-channel into the back of the mantel along its full length to act as a stiffener. That, combined with the material removal, should keep the piece stable over time and minimize any wood movement once it’s hanging on the wall. After all that, I ran it across the jointer a couple more times to make sure the back face was dead flat — so it would sit tight against the marble surround with no gaps.
Finishing Up
With everything shaped, drilled, lightened, and stiffened, the last step was getting a finish on it and shipping it off. A short while later, the client sent me a couple of photos of it installed. It looked exactly like what we’d talked about at the start — smooth, flowing, like it just kind of grew out of the wall.
Projects like this one are a good reminder that you don’t always need a CNC or a massive shop to pull off complex organic shapes. Sometimes it’s just templates, a power carver, some chalk, and a lot of patience.
I’m the owner of Benham Design Concepts, a mixed media art studio where I design and build custom furniture and other works of art using wood, glass, stone, and various metals.
In this blog, I talk about the art I create, my journey, and the things I learn along the way.