I’m bending cedar shingles to set on my rolled edges of my roof. I’ve found a system that works. Sort of..
Soak the shingle in the lake, then go swimming that night and recover them when I didn’t put enough stones on them to properly weight them down ;-( put more stones on top of them and go swimming a few days later when really big boats kicked up some waves and nearly a whole square was floating off..
get some big plastic tubs and soak shingles in for about two weeks. 😉
now put a shingle in the microwave for 4 minutes and then into the stem bending form for 4 mutes with an extremely heavy weight (64 pounds) with the proper radius on it and in the form. Pull out of the steam box and quickly run it up to the edge of the roof and nail it top, middle, and bottom, who cares if the stainless steel staples show because otherwise the shingle will slowly curl back up.
Hopefully at some point I’ll be able to remove the staples from the bottom once a few years have gone by and they’ve learned their place in life..
Now these are for regular sixteen inch shingles not shakes.. I couldn’t get shakes to bend no matter how long I steamed them. (I TRIED UP TO 8 HOURS) around an 18 inch radius.
now the edge of my dormers and my tower all have about a 6 inch radius which I simply cannot figure out a way to bend around.. I lose about one in 5 shingles with the 18 inch radius even though I keep them all around 4 inches wide.
Any suggestions?
I saw a few articles in FINE HOME BUILDING showing it done but none of the articles had details.
Replies
Frenchy, I've bent quite a bit of wood and I think you really need a proper steam box. Make one out of plywood with rigid foam insulation. Use a wallpaper steamer to provide the steam. Make it just big enough to fit a dozen or so shingles. An hour or two should be enough time to make them very pliable.
Don't use wide shingles. 4" to 6" is probably the sweet spot. Just rip wider ones down. I know it seems like they'll save time but they won't, they'll crack.
Next, you need a proper bending form. I would try a two-part form, made from plywood glued and screwed together. The inside edges of the form halves will have a slightly tighter radius than you want to end up with. I'd count on 10% to 20% springback, so make the radius 5". The outside of the forms should be straight so you can clamp them together. 60# isn't a heavy enough weight. You need a couple hundred pounds of force to get the shingles to do what you want.
The key is to let the shingles cool down and partially dry out in the form. Make the form big enough for four shingles. Make three forms and you can bend a dozen shingles. I'd expect 50% waste anyway, so bend 12 shingles and you might get 6 you can use.
Couple of other things. Are the shingles A-A extra clear/blue label/perfections? The grain has to be absolutely perfect or forget it.
I know you like using local mills, which is great--have you found a mill who can give you perfect shingles that haven't been kiln-dried? Kiln-drying makes the grain brittle. That might be the biggest key to your problem right there.
MIKE,
Ah the internet,, If I post all the details I risk nobody reading it because it's a book, if I quickly gloss over the details then I spend a lot of time retyping those same details,,
The steam box is a proper steam form, it has the female shape I need to achieve while allowing steam to flow thru even while the shingle is in the form. the steel pipe used weighs 64 pounds and has the proper male shape I am trying to achieve.It remains in the box all the time so it stays at steam temp..
You are right 4 inches works best.. so I microwave two 4 inch shingles at a time and place the in the steam box after 4 minutes of microwaving.. (more microwaveing time tends to dry out the shingles, less and they aren't as pliable) then they get about 5 minutes in the form.
The orginal attempt was for 4 feet of shingles at a time. so coming down to two 4 inchers is frustrating.
Yes they are blue perfections plus they come green as heck! dripping moisture and shrink a bit when they actaully dry out but that;s OK they bend nicer that way..
It is always a fine balance between too much information and not enough.
I still think you should try a steam BOX, just an empty box, then take the shingles out of the box and clamp them in a form until they're cooled down and dry. I've heard of your method but never tried it--mine works too well ;-)
While one batch is cooling down ON THE FORM, another gets thrown in the steamer to cook.
If you could blast the shingles on the form with dry heat you could drive out the moisture more quickly. Maybe put them in an oven at 250°?
Mike,
Do you believe a 6 inch radius is doable? I mean I can cheat a lot and maybe use a seven eight noine inch radius heck maybe even work with a 12 inch radius worst comes to worst..
I forgot to ask, is this red cedar or white cedar? If white, I would say it's definitely possible, if pushing the limits. If red, which it probably is being a roof, it's more brittle than white. I've glue-laminated red cedar but don't recall steam bending it.
I would make up one 5 or 6 inch form (male/female). Steam the shingles for two hours. Take them out of the steamer and start clamping them. When you start hearing a lot of cracking, check the radius of the shingle at that point. There's your safe limit. You can push it a little and have more waste.
Piffin advises soaking shingle in a hot bathtub to soften them up. Wouldn't hurt to start with an overnight soak before steaming them.
Mike,
I have soaked various lengths but to be fair never in a bathtub. water would quickly cool off unless you stayed right there so I'm not sure how much help hot water would be..
OH, red cedar
Edited 9/15/2007 12:31 pm ET by frenchy
frenchy---try soaking them in a solution of hot,Hot,HOT water and Downey fabric softener
Stephen
Cream rinse for hair works better.Spheramid Enterprises Architectural Woodworks
"If you want something you've never had, do something you've never done"
Mike,
I tried to bend them with just the steam box and they never got pliable enough to bend nicely. I even went as long as 8 hours. The microwave seemed to be the real answer. three to 4 minutes.. then four or five in the steam box while they are being shaped.
I've seen some boxes that use the lid as the male form but wondered how they kept the steam in with the lid partially open..
I faced a similar situation a few months back. Fortunately, my radius was gentle enough not to require steaming/soaking in a lake/whatever. However, what i did learn was that handnailing with 5d SS ring shank nails was alot more effective than using 7/16" crown staples. You can nail it in and then go back in forth between the 2 or 3 nails you've driven to slowly pull it tight to the wall. good luck...
thebozer,
Yeh I found that out as well, I set the stapler to leave the shingle loose and tap each leg in gently with a hammer untill everything is snug.. Carefull not to break the fibers.. Patience certainly is called for.. plus I can't do everything myself which is really painfull..
Steaming Pressure Treated Taper Sawn shingles
Has anyone steamed Pressure Treated Taper Sawn Shingles? I have done it with Red cedar Perfections. It is for an eyebrow dormer, pretty staright forward when steamed correctly. Any thoughts?