Thread: Bending Wood

Gidday Chris
Mate I saw a thing on the idiot box awhile back about Tassie and they showed this old timey town setup and going through they entered this bloody great shed where a fella was doin just that as they had been doin

just like that


for centuries!

Actually not takin the phiss mate just sayin it aint new is all although they may think it is its not... the setup this bloke had was like a bloody great table with wooden rollers along it and a huge barrel the wet steamed timber planks were bought to the barrel locked into place by way of wooden peg like things then the bloke turned a friggin great wheel and the barrel turned the plank moved around the barrel and ended in a U shape just as you say... leave let dry and bobs yer uncle

Cheers!! Great how some things we think are new and whacketty dak are actually ancient and been happenin for donkeys years eh

Mini,

You or anyone else didn't happen to take any Pix did you?

We have some leather [say it softly - Ikea] Poang chairs which are a laminated timber with no back legs - a "U" on its side - they rock and are extremely comfortable. Have alway wondered if it could be done out of solid timber without a series of kerfing cuts.

Regards,
Bob

Dingo, one thing we all know, there is nothing new in this world. The only new thing here was I had never seen it done like this. Bob, if I remember I will take a camera next week and get some photos.

Cross posting there Chris... as I said I wasnt having a go or takin the phiss out of you sorry if it came out that way it wasnt intended

ahem...

Gidday Bob

Firstly it would depend on the timber specie you want to use... some specie are more adept at bending without splitting cracking etc than others

Second on the radia of the U you want to create

It is easy enough to form a curve rather than a U by steam and then on a form bend it to a sweeping curve

As Ramps found recently when he did the stems on his canoe out of Jarrah the tighter the curve the less likely timber such as a hardwood like Jarrah will bend to fit... he found Jarrah broke at the radius he wanted so he tried Sheoak and it bent perfectly to the form

The Jarrah will bend... but will more likely than not break on a more forced curve than a sweeping bend

Another way to successfully bend timber is with the use of laminates of hardwood... so make some 1/4in or less strips longer than what your final length will be make a form this can be as simple as some ply with blocks spaced around the curve you want... and steam the laminates then clamp them to the formwork and let dry... you will get some degree of springback but you can minimise the impact of this on the final product by making the blocks slightly inside the line of the form

You could try a simple test for yourself on some timber you have that you want to use by doing the following

Make a steam box about 5ft long... make it out of 1in x 6in Pinus crapiata... at one end make a door and hinge it... at the other leave it open and get some rags to stopper it... if this wasnt just as a field test we would create a better end than this but for now for this test just stuff the end with rags... at 6in intervals along the sides drill holes either side large enough to slot some dowel through... your timber will lay on this while being steamed.

Now you need a source of steam... I use a bloody great stew pot I nicked from my sis's partner when the hospital she was working at was having a clearout... and then a heat source the barbie is actually good enough take of the grill so you sit the steamer directly on the flames... so now you need to get the steam to the box... so hoist the box onto a stand you can make out of whatever is on hand just so one end is slightly higher than the other and about 6in of the pots top... you need to have a slope so the condensation goes down the box toward the ragged end where you have drilled a hole for it to escape... connect the top to the box by way of a small hose fixed to both the top and box (drill a hole and slide the hose into the top of the lid down just above the water level... you want steam not water... and use one of those small hose clamps at the box end)

Okay connected up? your ready to go!... arc up the barbie get the water to burbling so steams going nuts then stick some lengths of varying thickness timbers inside the box and stuff the end go have a beer... depending on the specie and the thicknesses some will take some time others will be pretty quick... now come back get some heavy gloves on and stand to one side and unplug the bung end standing clear of the steam (IT WILL BURN so stay clear) take out the floppiest peice and move it quickly to the form and clamp it up... if need be have someone else stick the bung back in as your gonna have to move to get the clamps done before the timber sets

And there you have it

This should tell you what specie you have that will bend to the curve you want it should also tell you the best thickness to use to bend to the curve you want... you might get a good surprise as to which timber specie will bend and conform to the mould

Important note here... STEAM CAN BURN... so use your head and think safe use thick gloves stand to one side of the box ANYTIME you or someone else is opening it and have the mould set up right near the box say less than 4ft away so you can take the timber out and to the mould.

Get back with your results

BTW they were bending Oak, which is fairly tough.

Originally Posted by Mini

BTW they were bending Oak, which is fairly tough.

And not to belay the issue Chris but the yanks an poms have been bending oak for boatbuilding for donkeys years

aahh geez Im on a friggin roll today!! stop it yer wally!!

Originally Posted by Bob38S

Mini,

You or anyone else didn't happen to take any Pix did you?

Bob

see http://www.woodworkingseminars.com/index.php?paged=2

a 1 hr seminar on wood bending


regards
woodcutta

Thanks for the link woodcutta. First step towards that steam bent rocking chair ive always wanted to build

Mini, Dingo and Woodcutta,

Many thanks, appreciate your time and responses.

Dingo, have copied and saved your instructions.

Woodcutta, have bookmarked the podcast and will download it next month - getting near my Bigpuddle limit and don't wish to add to their CEO's retirement package.

Regards,
Bob