Printable View
A new job I have calls for bending some red oak into a 180 degree arc with a 12" radius, and I'm looking for some advice. I've read some old threads describing soaking it in water with fabric softener.
I'd like to end up with about a 3/4" thickness and a 3" width. I'm assuming the best way is to laminate 3 pcs. of 1/4" bent stock, or would 2 pcs. of 3/8 thick work?
I'd appreciate any ideas on accomplishing this.....thanks.
Oh yeah - I don't have a steaming unit made, and am wondering if it would be an advantage to making one for this small a project.
It will be a lot easier and you will get less springback if you use 1/8" oak for such a small radius.
I agree with Ralph. Make the steam bender. It's cheap and easy.
I third the motion for a steam bender. I doubt you could get that radius via any other method that I know of.
That is a pretty tight radius to bend with oak. If you decide to use steam, which will help, you must work very quickly. The wood will cool very fast and any advantage to the steam will be lost in seconds.
I would suggest that you use as many plys as possible, at least six @ 1/8". Make the strips as long as you can to help make it easier to bend.
Here is the tough part, you should over bend the parts to allow for spring back, which you will get and the amount is variable.
Richard
Steam bending might allow you bend a piece of 3/4 x 3 oak but making the steam box is a lot of work for something that might not work. I would make that using thin veneers (thockness plane to < 1/8") and glue it up in a male/female mold.
I made the steam unit that Norm has (metal gas can over propane fire feeding 4" PVC pipe) and steaming something as thick as you are talking would take a long time. I think the rule is an hour for every inch of thickness so 45 min. Thats way more time than making 6 or 7 strips ould take.
On the other hand, the steam genny is cool and opens up new doors for future projects plus your buddies will think youve harnessed the power of nature and that has some benefits.
Steam bent wood cools in about 30 seconds so theres not much time to get it in the form and clamp. Risky for an hour of steaming.
Good luck. Ben
Bent laminations is the way to go for me. I did a sled several years ago and did just about what you want to do. I used 1/8" laminations and Gorilla glue. Tightbond II would work but mine was for a wet outside use. Make a bending form, cover all the surfaces with duct tape and get lots and lots of clamps.
http://home.metrocast.net/~cpjvkj/sled.jpg
CPeter
Mike! I have bent a lot of wood. Thin lams are probably the easiest/fastest way to go. The downside of that idea is you need to make it wider than 3" because the bits slip a little and whatnot and the glueline can wonder on you if you don't have clamps everywhere, like every 2". Then you have this wider than 3" piece you need to trim up flush and whatnot and that is kinda akward.
If you bend the whole thing at once, 3" is a wide piece and there won't be much finesse to it. A piece of stovepipe and some aluminum foil over a stove or a campstove and a pot and you have a steamer. You steam it for a long time and they are right you want an hour or so for a big thick piece like that then you want to pull it out and stick it on a form real quick but it is wet and heated by steam so this is hard to do. One end of the form you want a block on the outside to trap the piece so you can just stick it in and start bending. It is helpful to have a backstrap along the outside of the wood like some metal strapping or something to keep from raising splinters and it is clamped at both ends of the piece you are bending. The heat from the steam does start to dissipate real quick but you can supplement it with a heatgun and get results that way. I kinda think you would again want a piece slightly wider than your target width because the sides will mush a bit.
Pick a real straight grained board it won't splinter on you as easily. If you can use white oak and cheat it is known for bending very easy with heat/steam. I don't mean to offend by giving the dictionary but there are a lot of hints/tips to bending wood, kinda food for thought.
Josh has a great posting here and I would only add that the wood for bending must be green - - the fresher the better. White oak bends very nicely, red oak somewhat less easily/nicely. Make sure you have all the parts to the bending form pre-situated before that bending piece comes out of the pipe! No time to be looking for pegs and wedges, the system I use on the outside of the workpiece. Just don't try to bend the wood before it is "cooked" for an hour. Wide and thick wood is obviously more difficult to bend than narrow and thin. I recently bent a 3" x 5/8" piece of holly and it was very difficult after about 30 seconds but I got it done and "the books" say you should not try to bend holly. Also, don't be afraid to fail on the first try. Experience in these matters helps. Good luck! Phil
mike, i too regularly bend wood to exact radiuses such as for use in window and door construction. when doing a window or jamb head, 4-6" deap i prefer to brick-stack a substraight, cut my inner radius on the bandsaw and veneer the inner face using a vacuum press......02 tod
Thanks for the responses, guys.
The application is a window in a 2" red oak door which will be stained, so white oak sounds like the way to go. Only the edges of the lamination will be visible to any degree. And since it's a double pane window, I can use narrower strips - maybe 1.5" wide to allow for trimming to width - and use spacers between the panes. I've since decided to go with a 9" radius - 18" overall width at the bottom, and it sounds feasible with the advice given here.
mike, lotsa door mfgrs. sell "window kits" to retrofit doors......before you spend the time building a window check with your glass company, the cost of tempered thermopane glass may be more than you can buy the entire assembly for.......just something to think about....02 tod
It you choose to laminate it, pick a plank which is primarily quarter- or rift-sawn on the face which will have visible seams. The seams blend into the long grain lines of the rift-sawn oak, and become nearly invisible.