Reading an Osage stave

[Kirkll]

OK.... I put the limb tip in a coffee can and brought the water to a boil and let it steam for about 30 minutes, then put it in the clamps on a piece of angle iron. As i straightened it out i used a heat gun on it...... We'll see how straight it stays after it dries good. I'll bring it in the house and let it set a few days before pulling the clamps loose.  I only did the side grain bend first and just added a wee bit of pressure on the belly to back side. 

I cut that knot out of it when rough shaping it but i don't want to push my luck trying to do too much at once. I may wait until i get my tips thinned down a bit before trying to get a reflex bend. That area where the knot was located looks like a potential weak spot.... Steady as she goes...

https://photos.app.goo.gl/5fd1BCNEuixWtGTv5

Kirk

[Pat B]

You got that straighter than I thought on the first try. You can probably adjust the last little bit when shaping the tips.

[Bowjunkie]

Here's a buffalo horn tip. I may vary the grind angle a bit from bow to bow depending on the outer limb shape.

[Kirkll]

THAT..... Is a beautiful tip overlay brutha! I might have to give that a go.

Pat, I was actually surprised how easily that kink in the limb straightened out. But that is a rather large C clamp i used too. I believe soaking it and steaming it in boiling water for 30 minutes had something to do with it.  We will see how much spring back it has after i pull the clamps. I'm going to build a radius form to reflex the tips a bit on the flat grain side next.

Back when i was building radius top doors for fancy boats, i came up with the idea of building them pre-hung in the cabinet shop.  Rather than bending the top of the finished door frame in place in the door rough opening, and fitting each door to the frame. (Like they had been doing) I could use a true radius, build the doors and frames in the shop and adjust the reveal while hanging the pre hung door. I scored a few points with the cabinet shop foreman coming up with that system.  :saywhat:The guys i worked with at Christensen Motor Yacht were a serious collection of craftsmen. Luthiers and fine furniture builders that could inlay your signature in mother of pearl.  It was an incredible experience working with the old school craftsmen.....Back in the late 80's a lot of that work was still being done by hand. Now days CNC production has taken a lot of the hand work out of play.

But back to my point about wood bending.... What i found building radius top doors was that different types of hardwood have different spring back after bending them in the same form using the same thickness laminations. For example Sitka spruce and Sycamore would have a lot more spring back than Honduras Mahogany, or Teak. And the Teak had more that the Mahogany too.  So it was kind of tricky to build door frames to match a true radius door top because you had to calculate the spring back, and use a tighter radius on your form So it fit the door top in a relaxed position. We used a lot of Urac 185 in our lamination work, and a lot of West Systems epoxy too.  Believe it or not the type of glue had no effect on spring back.   So i'll be curios to see how much it moves.

I think some of the wildest wood bending i ever did was building a free standing spiral stair case out of solid Teak on the aft deck of one of those fancy yachts. That my friends was a wild project.

Kirk

[Mad Max]

I bet it was very cool doing that kind of fancy work.

I did some Ornamental Iron work for 12 years and always want to do a curved stairway. and I got my chance.
It was about 110* turn to the upper floor. I took my roll bender on site and curved and twisted the upper and lower rails until I got them fitting. I screw my post (4 I think) to the treads  and cut the curved pieces to weld to the post, brace it all up and took it back to the shop to finish later. the Treads were plywood when I mocked it up and Oak after they finished . I was very proud of the work I did over the years.

[Kirkll]

I cant imagine doing that out of steel. Wow! i'll bet that was intense.

 I've done quite a few spiral stair case railing systems and bent the rails in the field solo. But that free standing job on the yacht was a full 360 degree with no post. That inside stringer looked like a cork screw. Only had a 12' inside radius, and the outside was about 3' giving us a 30" wide tread.  We had to build two forms. Inside and outside, and used 1/4" solid Teak for laminations.... A whole lot of laminations too.    It took 2 of us about 6 weeks to put that thing together, and we had more guys handy doing the cork screw lay ups....   Fun days.... Dirt cheap wages... I loved that job.    Kirk

[Mad Max]

 

[Kirkll]

Here's a buffalo horn tip. I may vary the grind angle a bit from bow to bow depending on the outer limb shape.

Can you explain the different splice angle changing with the outer limb shape differences? I think i got it... but...     Kirk

[Pat B]

You might be surprised how little spring back you get. Osage bends easily with heat and seems to hold most of the bend. You can heat and readjust if needed. I think I'd wait until first brace before any more heat adjustment. At low brace the stave becomes a bow and you can see the real shape under tension and where adjustments are needed.
 I watched a show on PBS about building a Roman chariot I think they were in Egypt. These old world woodworkers steamed a 6"x 6" post for 6 hours in a big steam box then bent it into the desired shape. All with primitive tools and methods. Pretty cool.
 I've done lots of boat work but in the mechanical areas but saw lots of beautiful woodwork on the motor and blow boats at Harbor Town on Hilton Head. Is. SC.
 Kirk, I think we need to be asking you about heat bending wood. You are the expert in this group. 

[Kirkll]

 I’ve got a lot of experience stacked up over the years and learned a lot through trial and error. When  there was no one available for help or suggestions, I’d boldly go where I’ve never gone before. Sometimes you get da lion…. Sometimes da lion get you….

 But the word “expert” has an overtone I’m not comfortable with. How bout “seasoned craftsman” …. I can live with that one.  I’ll gladly share previous experience with folks, but you’ll  never learn it all our rather short life times.
Could you imagine the sum total of a man’s experience could be if we could
live 2-300 years and still retain the knowledge? Now THAT would be very cool.

I know self bows and moisture content is a big deal because it’s the moisture content that mitigates it’s flexibility to a certain point. But Bending wood with heat alone is still heating the moisture still inside the wood and making it more flexible while it’s hot. The higher the moisture content, the easier it will bend.

Where I live in Oregon, the average moisture content in all my shop wood stays real close to 12%. I can buy bone dry kiln dried lumber that is 8% and leave in in the shop for two weeks and it’s right at 12%  on the surface just like everything else. I have to be very careful to bring that mc level back down before I finish a riser or bow. Especially if it’s being shipped to a drier climate.

So part of my luck with getting this thing to bend so easily was most likely the mc level of the stave was higher than normal. That , and I soaked it in water for 12 hours then boiled it in hot water for 30 minutes. That being said, I’m going to let this set in my spray booth at low humidity lever for several days before I take the clamps off. A week would be better me thinks….. I’m in no hurry to get this thing done, but I will finish it now that I’ve started….    Kirk

[Kirkll]

One more thought here…. If you think about drying green wood it starts out freshly cut about 30-32% mc. When you rough cut this material and stack it up for air drying the most critical part is going from 30% down to 20% slowly by keeping it in the shade outside or inside a building with fans blowing through it is best. If it’s dried too quickly in the hot sun it always splits…. The question is why.

It’s the outside pores of the wood close and shrink when it dries, and the moisture inside the board is trapped inside. That’s why you see sprinklers on piles of logs at the lumber mills in the summer, so they don’t split open. If you are going to harvest and air dry your own wood, cut it in late September and dry it though the winter months. You’ll ge5 a much better yield.

Steaming wood before bending it helps open up those pores and let’s moisture inside making it more flexible and helps avoid tearing the grain on the outside and allows better compression flexibility too.  Most of my wood bending experience was done by cutting up big ones, to make little ones, to make big ones in the form of laminations with no steam at all until you get into tight radius work.

Food for thought… Kirk

[rainman]

J D Jones and Gary Davis, 2 of the best wood bowyers I have seen always used dry heat to bend Osage when they were building bows.  It is just one of those woods that it can take it, just like Bloodwood.  Both are in the Mulberry family.

[Stagmitis]

Dang Bowjunkie that is a beautifull tip overlay!!!!

[Kirkll]

Dang Bowjunkie that is a beautifull tip overlay!!!!

I agree staggy…. I think I’m going to try this on this Osage bow with some water Buffalo horn material.  That is so cool.      Kirk

[Kirkll]

I know i already posted this photo on another thread, but i thought i might add it here too to keep these pics all together. I was amazed how well a bit of steam and heat straightened out this stave tip with one shot.... i don't think there was any spring back at all.

Now i've got the other end to contend with that looks like a snake. One end has a perfect back set shape and i'm not sure if i can get this as nice as the the other end, but i'm going to give it a try.

This is what i'm dealing with.  I didn't mind soaking and steaming the tip on one end, but i'm not to thrilled with the idea of soaking the whole limb in water. Any suggestions would be appreciated.

Kirk



 

[Mad Max]

Nice work so far
Pat should be on here soon.

[Pat B]

You can get the hoopty doos out with dry heat. If you have a full length caul start clamping at the handle and work out the limb with a heat gun. I go n 6" heating's and clamp them move out to the next 6". I usually use cooking oil to keep from scorching the wood during straightening. When you get to the end of that limb start on the other limb.
 If you don't have a full length caul you can work the kinks in the limb out one at a time with heat, oil, clamps and and a piece of 2x4.

[Kirkll]

Pardon my ignorance Pat…. But I’m not familiar with the word caul. Are you referring to a form that the stave is clamped to?   Kirk

[Mad Max]

Pardon my ignorance Pat…. But I’m not familiar with the word caul. Are you referring to a form that the stave is clamped to?   Kirk

Yes

[Pat B]

Yes, a caul is a form.