bending and breaking cuban mahogany

[mike-p]

Managed to break both sides of a set of cuban reclaimed from old furniture. Have bent honduran and walnut on the same mould using a fox-ish style bender with heat mat. Sides were around 2mm which seems right and they felt ready to bend, took them to a little over 100deg C, bent them and cooked them for five mins. The first I did a little hotter and wetter, the next cooler and drier, first had 2 crack right across the grain, the second, one. My main suspect is that I used quite floppy aluminium slats instead of steel and they didnt provide enough support but any experience/advice appreciated as the set was not that cheap or easy to get hold of and was absolutely beautiful!

[ken cierp]

It the tension that is applied that counts not the stiffness of the slats. Our machines have aluminum covered forms and the outer slats are .023" 6061 aluminum. Our cutaway bender does have SS for the outer slat -- but it is only .007" thick. Look at the videos of the factory automated and semi automated side benders what they all have in common is the tension factor on the compression side of the bend. Screwing around with 2 layers of stiff spring or stainless steel slats will make you sad. $.02

[ken cierp]

Also, Mahogany has interlocking cross grain -- in my view making it is one of the most difficult woods to bend. You don't notice right away but once you put water on it, waves/ripples form across the width. This compounds the problem because heat is no longer distributed evenly on the surface since the ripples cause gaps against the blanket. I have not bent figured Mahogany in a while, but I actually boil it! If you clamp it tightly it comes off the bender flat once its completely dry.

[mike-p]

all interesting info, a friend of mine built a steam box, steamed the sides and then put them in a mould to dry, worked fine apparently.

[mike-p]

Is there any disadvantage to boiling the sides and what sorry odd technique and timings do you use?
Thanks.

[mike-p]

Sorry, sort of, not sorry old!

[ken cierp]

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