Published Friday, November 18, 2022 by Bryan

So I had a few trees cut down to clear the sky for Starlink. It turns out there are a bunch of Wood-Mizer portable sawmill owners that you can just call and pay to cut logs into lumber for you.

Clearing freshly sawn lumber off the portable mill.
A few hundred boardfeet of red oak stacked to dry.

So I did that, and now I have a garage full of lumber that needs to dry for another several months at least. It's enough wood that I'll be using it for years to come, but I sure would like to try some now. What can I do with wet wood?

My new solid red oak toboggan.

Bend it! At some point in the future, I'll build a boat, like all the other woodworkers have done over the shelter-in-place era. But to dip my toes into the (frozen) water, I decided to start smaller: a toboggan.

But first I needed a steam box. Why use dry wood for a box that's going to be filled with wet air? To the garage!

Moisture meter pressed into a freshly-cut edge reading 15%.

Fifteen percent moisture, I'm told is dry enough to be used in outdoor structures like decking. I don't have a SawStop, so I don't have to worry about triggering its safeties.

Red oak is roughly half of the lumber I have. It has never been my favorite, so it made sense to experiment with it on a project that may fail.

Lots of color and figure in some of this oak.

But maybe also I might change my mind on red oak. These first couple boards have some beautiful patterns in their grain. They really planed and jointed nicely.

Basic steam box, with turkey frying thermometer for measurement. Hose leads to wallpaper steamer, out of frame.

A bit of slicing and screwing later, and I had a steam box! It's not perfect, but it holds tight enough to get to temperature without exploding.

First attempts at bending. Areas of success surrounded by areas of failure.

My first tests weren't great. I was pretty aggressive on the steam timing, as well as on the bend radius. But time is easy to adjust and the radius for a toboggan is much larger than my attempts here. I forged onward.

Routing a 12-inch diameter cylinder to use as a bending jig.
A claw on top and a straight edge on the bottom complete the jig.

First I needed a proper bending jig. I just clamped to paint cans for testing, but I wanted a sturdy 12in (30cm) diameter circle for the real deal. Using the same compass jig for my router that I used with my mailbox, I was able to quickly knock that together. A claw to hold the end of the board, and a straight edge to lead the rest of the runner out of the curve were quick additions.

Glue drying on four drying forms.

Since this bending form will only hold one slat at a time, and prevents the inner face from drying out while doing so, I also knocked together a few drying forms. How they fit will be demonstrated in a moment.

Eight slats, 3.5 inches wide, 1/4 inch thick, and six feet long. Impossible to get a photo angle that captures the shape in a way that makes sense.

I resawed four pieces of 6ft (1.8m) 1x4 into eight pieces, each just over 1/4in (65mm) thick, to use for the toboggan runners. I only needed five for one toboggan, but every tutorial stressed preparing extras for the inevitable bend failure - which my tests seemed to support.

The last 18 inches of the slats are soaking in a trash can full of water.

Also suggested in many tutorials is pre-soaking the wood, if it has dried at all since milling. I'm only four to five months in, but given my splintered test strips, it sounded like a good idea.

The last 30 inches of a slat steaming in the box. Yes, that's a shower stall. Why not steam and drip in a space that's meant to handle steam and drips?

Almost 48hr later, I finally got the steam box heated up again, and stuck the first piece in for 30min. The inside of the box is 30in (76cm), so most of the runner sticks out the front of the box. But, I'm only going to bend about 20in of the board anyway.

Slat bent around form and clamped in place.

Out of the box and immediately around the form. The first went absolutely perfectly. No struggle, no cracks. Same for the second, third, fourth, and fifth! No failures at all. I was floored.

Okay, that's actually a little bit of a pun. The floor did, I believe, actually have something to do with it. Another tip many tutorials give is to use a metal backing strip on the outside of the piece as you push it around the form. This supports the wood fibers, so they don't splinter off. A video from HoneyBadger WoodWorks offered another solution: press the form and the piece against a surface while rolling. That's what I did - stuck the end of the board in the claw, laid the board on the floor, and then rolled the form onto the board while pressing it toward the floor. I could then put the first few clamps on before tipping the form onto its side to clamp the rest of the board.

Four bent slats drying in open frames.

It worked pretty well to leave each slat clamped to the form for 30 minutes while the next slat sat in the steam. At the end of the steam time, I would pop the bent slat off the form and move it into a drying clamp. The inner dimensions of the drying rack frame are identical to the outer cross section of bending form plus slat. The bend mostly held itself after 30 minutes of cooling, but the drying form helped fight against springback while the inner face dried.

Two nice bends and one half-cracked. What will I use them for?

I did go back and bend the remaining three slats, since I had already soaked them. I finally had one fail there. I think it was mostly due to placing it in the form's claw crooked, and then trying to correct after having rolled a bit. That added a twist to the roll, which was more tension than the wood could bear. Maybe it also had something to do with that piece being quartersawn instead of plainsawn. All of my failed test pieces were quartersawn. None of my plainsawn toboggan pieces failed. But other quartersawn pieces did just fine with the toboggan form (what became the center strip, plus the other two extras). More data is needed to be sure.

Ribs ready to pin across the skis, with the heads of the skis slotted into the headboard.
Pretty streaked grain across the face of the headboard.

To turn the single runners into a toboggan, they need to be held together. This is done by fastening ribs to the top. I found them in the offcuts from the original 1x4 slat material. The piece at the end of one of the quartersawn boards had the prettiest medulary ray stiping across it, so it became the head board.

Every tutorial I read or watched suggested screwing the ribs to the skis. That just looked wrong to me. A hundred bits of metal in this otherwise simple oak form just didn't seem right. The argument for screws was always that you didn't want to glue the rib to the ski, because you needed the ski to shrink and grow with humidity changes. But then everyone put two screws through each ski, effectively constraining the width of the ski.

Towing bumper pinned in place with glued dowels.

I decided that I'd take one more risk and glue in dowels to pin the skis to the ribs instead. A quick jig turned some of the remaining scrap into precise-fitting dowels, and then it was just a matter of clamping and drilling. I still used glue sparingly - only around the dowels, and not between the faces of the ribs and skis - so hopefully there's a little room for movement if it is needed.

Rope strung through holes in the ribs from back to front and back again.

Each rib also has a hole drilled through it. This is to allow a rope to feed through. The rope runs from one side of the rear rib, through each rib toward the front, up through the headboard, then back down through the other side, and out to through the other side of the ribs. This gives a little extra support - holding the front down when things bump into it, and helping to keep the seat flat over bumps. It will also provide a place to fasten a seat pad, if I ever get around to making one.

After finish, the streaked grain in the headboard pops even more.
The finish also highlights the endgrain in the dowel pins holding each of the ribs.

I used spray-on spar urethane to finish. I will also likely wax the bottom at some point. It looks and feels nice, and I hope will provide just enough protection against ice abrasion and snow melt.

Test rides in the first snow accumulation of the season.

The test. Somehow the stars aligned and a week after I finished the toboggan, four inches of snow covered our hill out back. It works! It was kind of sticky snow, but it slid down it just fine anyway. I think we're going to have a lot of fun with it this winter.

Categories: Woodworking