I have to bend some 5/4 mahogany – 6″ wide by 9′ length – by a radius of 6 1/2 ‘. Actually, only a four foot section of the 9’ length requires the bend (it’s for jambs for church doors with a gothic arch at the top). Any advice on the best way to make the bend?
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Mahogany is difficult to steam bend. Bent lamination would be a better approach.
Do you have any thicker stock you can use? If so, I highly reccommend resawing the stock into 1/8" slices, being careful to keep them in order. Then you build a form out of MDF in the shape of your bend. Glue all the slices back together using a urea-formaldehyde glue, clamp them to your (pre-waxed) form and you're there.
I like this method much better than steam bending, as you have much more control over the final bend. With steam bending it is very difficult to guage how much "spring back" you are going to get.
If you're sure it's mahogany needed, then so it is.
Most churches with gothic arches use oak. And oak is one of the best woods for steam-bending.
Will, I would suggest using a brick layered technique so that you can saw out the radius you want without the worry of spring back or bending failure. Then if you wnt to hide the seams then laminate a thin veneer over top. You did not mention details of the door stop. Is it to appear as a rebated stop? If so then the stacked lamination should work well. This technique has been used for centuries and results in a very strong curved form.
J.P.
I have bent mahogany with hot water only and hot water with a bottle of fabric softner ( Downy is the brand I used.The radius was longer than 6'-6" though, the stock was 4/4. If you try this method you will need a trough or tub , hot water, the hotter the better. Water should cover area that is to be bent by several inches. Add fabric softner and stir in. Let soak 30 minutes, add more hot or boiling water as needed. You want to immerse the bent portion in hot water and then bring up to a form. I would fasten 6" blocking with screws on a sheet of plywood to form the radius.Make sure someone helps you as you clamp and pull the jamb around the form. Leave set for 24 hrs. You may get some springback but the side jambs fastened to the bent piece will easily pull it back to an arch.
Select straight grained wood for the jambs. I have found mahogany bends well, ash,white oak etc bend easier but I had good luck with mahogany.
mike
Will
I have bent to many of those and the way i would do it(others have said the same thing) is to cut my Mahogany into thin strips, 1/8" sounds good. Make a form out of ply or particle board and put it in there, a little spring back wont hurt any, when you install the jamb you can shhim it to the proper place. Need more info just ask.
Doug
Will:
That is too thick and wide for steam bending. As others have noted, lamination is the way to go, unless the configuration is such that you can use hidden kerfs to make the bend. You don't mention the orientation of the bend.
J Painter