Steaming Cedar Shingles

I've never steam bent anything, and now I need to steam bend some 16" perfection shingles, all VG.

I don't need to do many, maybe 16' worth of a single course, and it's not going to be much of a curve.

I ordered a wallpaper steamer, and my plan is to get an 8' section of 18" diameter sono tube, stick all the shingles in there (after soaking in water for 10 minutes) and start steamin!

I think I have it all figured out except how to seal the ends of the 18" cylinder while it's steaming. I could cut two 18" circles out of plywood and use those, but was wondering if someone had a better idea of how to seal the ends??

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Originally Posted by Joe Wood

... and it's not going to be much of a curve.

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I put cedar shakes on all my dormers, so some experience - - but not really an answer to your steaming question. I believe the typical method to deal with curves is to simply use narrow shakes. They sit flat enough to nail and for a gentle curve, this is adequate. Wide ones can be split vertically to allow use, but even the wide ones, when new, should bend enough for a ~6' to 8' diameter structure.

I used white cedar machine grooved, R&R (18" nom. length, 3"->14" random width, 5/2 butt). I disposed of a 6-yr-old partial box a couple of months ago and noticed they are quite dry and brittle now. ...So, use 'em or lose 'em.

Your circles of plywood will work fine as some leakage is necessary to let the steam out.

I recently set up a steam box (mine's rectangular). After a couple runs I insulated the box and got much better results. I also added a thermometer. the wood doesn't soften much until you get to 210 degrees. Depending on the radius you are going for I would guess 30 minutes at temp would do it.

I also ended up making a sheet metal strap with end blocks to keep the outside in compression. This reduced my failure rate dramatically (50% down to 10%)

Unless you leave spaces between each shingle it is going to take a long time to get all the shingles hot. The ones in the middle of the stack are not going to see steam or heat for quite a while.

I would throw the shingles in a barrel of water and let them soak for a week then try bending them cold.

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Originally Posted by Bill Dufour

I would throw the shingles in a barrel of water and let them soak for a week then try bending them cold.

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This is how I have always done it for curved edges and pitch changes. I drop a couple of bundles in a drum and build a fire under it. Worked well for me. As they are soaked I do not allow for spacing, push down firmly before stapling, good to go.

All good advice, let me add a bit more;

That's a mighty big steam chest. You don't have nearly enough steam.

It will be almost impossible to get the interior shingles hot, downsize to just a few shingles at a time.

Definitely use a thermometer. Steam will leak out for quite a while before the temp comes up and until it does you are not softening the wood at all.

A steaming setup is not a casual affair, a few failures are possible before you get it right.