Thread: Bending moments

Hmm, Perth, WA - Check these two threads out.

Thread 1

Thread 2

cheers
Wendy

Must be a different Jack-Plane

Nope, he's definitely not me!

Regards,

Jack Plane.

Pegs and 'Tails

i just completed a steam bending course with david haig. he explained to us how this is done, i shall tell you the short version. basically the timber is put in a compressing machine, so the timber is being pressed inwards from both ends with extreme pressure. the timber compresses to about half its original length and is left to settle, after this time it goes back to around 3/4's its original length. this compression literally crushes the lignins (basically the natural adhesive which bonds the fibers within timber together), so once reheated by ways of steam (which is the perfect temprature (100 degrees celcius) for the lignins to melt and allow timber to be bent, not so much the fact that the steam and moisture gets back into the timber) the timber almost literally turns in to rubber, hence allowing the timber to be tied into a knot. just plain steam bending won't/shouldn't allow you to bend the timber so heavily. If you have any more questions please ask away and i'll do my best to answer them, he also tought us how to make a steaming box, which if not built properly turns into a bomb lol ... Hope this makes sence and helps you.

When the timber is being compressed is it in the heating chamber ?

Originally Posted by Jack-Plane

Hi All, this is my first post as a member of the forum so be gentle, i've got the shed and an old Robland combo which is still cranking out some accurate machining, so i want to turn my attention to some curved projects. I remember a few years ago at a wood show a guy demonstrating a steam box, out of it he produced a metre long 25mmx25mm piece of jarah and tied a knot in it, I would like to make my own box and wondered if anyone's up on the subject, i look forward to some pearls of wisdom.

Hi have a look at an instructional booklet put out by Veritas link is Veritas® Steam-Bending Instruction Booklet - Lee Valley Tools

Rgds

Originally Posted by Peter36

When the timber is being compressed is it in the heating chamber ?

sorry i can quite remember, although i'd say it has been steamed before. then again maybe not due to the fact that i would think the lignins would set after the compression.. so you will have to look into that unfortunatly.

Originally Posted by spencer411

sorry i can quite remember, although i'd say it has been steamed before. then again maybe not due to the fact that i would think the lignins would set after the compression.. so you will have to look into that unfortunatly.

I can't get my head around the timber being compressed to half it's original length. Seems one heck of a lot.

Originally Posted by Peter36

I can't get my head around the timber being compressed to half it's original length. Seems one heck of a lot.

I couldn't either. Here's a link including compression bending - about 10% rebounding to 5% is the figure.

me fail english? That's unpossible.