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Bending Walnut

Started by Patty, December 27, 2009, 10:44:21 AM

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Patty

I have this beautiful slab of walnut that I finished a few years back, and am finally getting around to cogitating a base for it.

My tentative plan right now is to bend a 1x12 walnut piece into a half circle, and then attach the slab to the top of the circle. The ends of the circle would be the legs. You see the half-circle turned upside down would form the base. Problem is I have no idea what so ever how to do this bending, or even if it is possible. Any helpful hints would be appreciated.
Women are Angels.
And when someone breaks our wings....
We simply continue to fly ........
on a broomstick.....
We are flexible like that.

DR_Buck

I've never done it myself, but I think the only way to bend something that size is to cut it into thin strips, use a bending fixture and laminate it .
Been there, done that.   Never got caught [/b]
Retired and not doing much anymore and still not getting caught

Burlkraft

Quote from: DR_Buck on December 27, 2009, 10:51:01 AM
I've never done it myself, but I think the only way to bend something that size is to cut it into thin strips, use a bending fixture and laminate it .

That's what I was just gonna say!

Great minds converge  ;D
Why not just 1 pain free day?

zopi

You can laminate it, or steam bend it, or bend it with anhydrous ammonia...me, I'd resaw it, steam it and mount it in a jig the shape I wanted it, let it cool and dry there, and
then pull it out of the form, and put it back layer by layer bonding it with marine epoxy...
Got Wood?
LT-15G GO chassis added.
WM sharpener and setter
And lots of junk.

Patty

That seems to be what they say when I googled it. I was hoping this might be easier than this. I am an "easy" project sort of person.  :D

Next question............how do I figure out the length  I need the strips to be. I know the height of the finished product, but what math equation do I use to figure the length of the strips needed before I bend them, to be sure the end result will be the correct height. Is this just a trial and error thing?
Women are Angels.
And when someone breaks our wings....
We simply continue to fly ........
on a broomstick.....
We are flexible like that.

beenthere

Patty
You want the length of the arc of a circle.
Google "length of an arc" and some formulas will come up, with diagrams.

If you want a circle form, then you may want the arc of a segment of that circle.

What length from the floor to the slab? And what length between the legs on the floor? Those are numbers needed to plug into the formulas that are available.

You might not want the segment of a circle, but a segment of an oval.
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

SwampDonkey

At first I was thinking of kerfing the inside arc of the bend with a radial arm saw. But you don't want to see the kerfs of course, so steam bending is the only option I see also.

I've never done any bending myself, so I'm not much help. I have some info in my Wood Worker's Manual but if you have never done it before you can't teach it. :D
"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

zopi

It's only hard the first time you do it....
Got Wood?
LT-15G GO chassis added.
WM sharpener and setter
And lots of junk.

DR_Buck

I went back and looked at your project idea again and I think the 1 x 12 is not going to be thick enough.   What is the thickness of the slab?  You may want to match the thickness of the slab  in the arc support leg to both support the mass as well as 'balance' the visual aspect of the finished table.
Been there, done that.   Never got caught [/b]
Retired and not doing much anymore and still not getting caught

Don_Papenburg

Patty , If you want to steam bend walnut you need straight grain air dried stock.  Rived is better than sawn.    You also need a thin metal backer (outside of the bend) that will keep the chances of a blowout to a minimum.  the larger the arc the easier it will bend.  NH3 will make it limp as an inertube .  But you will need a pressure chamber hooked to the vapor valve on the tank.  Soaking times are about the same as steam . One hour per inch of thickness. 
If you cut strips (the easyest method) use at least seven strips per arch.  seven or more strips makes springback almost a thing of the past.  Mark the center of the board  and make sure to coalate the strips as they come off the saw.  Use a hollow ground planner blade so you do not have to sand the strips.  The best glue for bent laminations  and veneering is Unibond 800 from Vacuum Pressing Systems.  Use the darker catalist , it comes in three shades ,light ,medium and dark
Wrap the stack of strips with shrink wrap or some thing simalar . That helps keep the srtips alined .  Use lots and lots of clamps   
With a 1/8 inch saw kerf you will need an inch and 7/8 of wood stock to start .
Frick saw mill  '58   820 John Deere power. Diamond T trucks

Patty

Good advice you guys, thank you.

I guess I have my work cut out for me.
Women are Angels.
And when someone breaks our wings....
We simply continue to fly ........
on a broomstick.....
We are flexible like that.

fiddle1

i was invited one time to an archery shop, where they build archery bows. 

archery bow makers have this two part form that they use of plywood.
They said they pattern route the template with a router and ball bearing bit.

this form they have is in two parts and they use this fire hose
with and air compressor to bend the laminations they put epoxy between the
the strips 1.3mm and then they compress it.

they do the resawing at bandsaw.

they also put saran wrap over the form cause they want to get the wood back off it.

firehose is like 65PSI over entire surface and the Shradder valve holds air in. 
one heck of a rubberband!


then they use heatlamps!  takes about a day to cure up hard, but often they leave it longer.

Cool thing is they too are using walnut and even tropical woods.

then whats even more awesome is they sand it back with drum sanders the edges are pristene
and shape doesnt springback much maybe .005mm over the entire arch. 

this method works great.

fiddle1

This was neat!





These pictures are from TAGE FRID TEACHES WOODWORKING.

This was the half circle mold and bending jig used.
Basically you start in the center and work toward the ends
alternating one clamp each side till you get squeeze out. The clamps get harder
to press as you get to the ends, which is why he suggests using a
SOCKET in an electric drill to get the mechanical advantage to set the clamps.

form is waxed so wood doesn't stick.

Don_Papenburg

If you clamp to hard you end up with bumps and depressions on the outer side of the lamination.
 

Patty do you have a vacuum pump system in your shop ? If you can find a vacuum pump Barrow the dairy farmers pipeline pump  but make sure you have it back by milking time . An old inner tube would work as a vacuum bag . With the bag you would not need as many clamps.  Just patch the leaks before the laminations are put in .  fold the open ends over and clamp solid and tight.Clamp at the mid spot and bend around the form and clamp a few times to hold the shape . Then hook to the vac pump and it will create the most even squeeezout
Frick saw mill  '58   820 John Deere power. Diamond T trucks

fiddle1

vacuum presses are expensive and hard to find.........
YES they do give more clamping pressure, but for a single project
it gets expensive?


with the clamps bumps and depressions are not a big problem.

if you use enough laminations the top .5 of a mm
can be sanded out with oscillating spindle sander or even a circular sander its just few minutes to get it flush.

just measure with calipers and keep it consistant.

you can place a support board of ply inside while sanding it free of bumps to keep it even.

Fla._Deadheader


  This roughly what you want to do, Patty ??

All truth passes through three stages:
   First, it is ridiculed;
   Second, it is violently opposed; and
   Third, it is accepted as self-evident.

-- Arthur Schopenhauer (1788-1860)

Patty

Holy Buckets Harold!  8) 8)

That is exactly what I want my table to look like! How did you know?!

I have been thinking about this all week; which is huge for Patty who has the attention span of a gnat.  ::)

So far I think the steam method is probably what I will try. The old teapot hooked to pvc pipe trick  ;)
Then it dawned on me that any pvc around here at the box stores would never hold a 12" wide laminated board. duh.. So now I am thinking maybe a couple 3" wide pieces would be easier to work with, and would actually fit into the pvc pipe I can buy. I am not sure they would be strong enough though. Around here little end tables or coffee tables always end up getting sat upon sooner or later.
Women are Angels.
And when someone breaks our wings....
We simply continue to fly ........
on a broomstick.....
We are flexible like that.

Patty

So Harold, did you make your table? If so, HOW???
Women are Angels.
And when someone breaks our wings....
We simply continue to fly ........
on a broomstick.....
We are flexible like that.

SwampDonkey

What about one of them old galvanized hot water tanks I used to see in the land fills?

Harold's quite the fellow to sneak stuff past us. :D
"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

Fla._Deadheader


Patty
I posted that a LONG time ago. It sits in the office of a Costa Rican Sawmill. The owner is mighty proud of it.  8) 8)  Notice the top of the curve is flat. You only need to bend 2 ends and just glue the middle flat.

  That is one chunk of tree.  I have thought about making one, myself, AND, I am about to cut the tree to do it with.

  Photo was hidden in the Archives from the FF meltdown, under my gallery name. Been wondering where all my photos went. Sure would like them back in my newer album.  ??? ??? ??? ??? ??? ???

  Patty, when I was in HS, back about 200 years ago  ::) ::), we made Mahogany Water Skis. We would cut the board twice on the bandsaw, so we had 3 "Layers" of wood to glue together. Cuts were about 12" into the flat of the 3/4 " board.

  Shop teacher had a "Jig Box" made up, that was 3/4 " plywood, about 8" wide. There were 2 sets of holes drilled through each side of the jig. Imagine the side of the jig looking like the shape of the Ski, with 2 layers of holes, one to bend the wood over, and, one to hold the wood down.

  We would soak the boards in a 5 gallon bucket, cold water. Next day, we would put the board in the jig, starting with the jig on the floor.

  Put a dowel through the jig on top of the board, so it was "Trained" to start the curve. Gently pry the board down, and insert more dowels as we went. Cold water is not good, but, beats dry wood. After maybe an hour, we would have the board doweled completely. The water softens the wood some, and provides a slicker surface for the cut pieces to slip as you bend the board. Boards HAVE to be perfectly parallel grain.

  2 days later, we would take the board out, smear Resorcinol glue (Elmers) marine waterproof, and re-set the board in the jig. 3 days later, take the board out and do another.

  You could use a stock tank with heater, and finish off by boiling water and soaking. Do part of the board at a time.

  Making a steam box is simple, also.

  NOW, if you use Gorilla Glue, and resaw the board(s), on the WM, you could speed up the process greatly, gluing wet wood as a laminate. No one will know the difference, especially if you lay a thin veneer on the glued up edges.

  Look up Steam Box, and bending lumber. It's not difficult, once you study up a little.

  TAKE PHOTOS, Por favor  8) 8) 8) :D :D :D
All truth passes through three stages:
   First, it is ridiculed;
   Second, it is violently opposed; and
   Third, it is accepted as self-evident.

-- Arthur Schopenhauer (1788-1860)

SwampDonkey

Harold your photos are still here, it's just that we never had any galleries. There is a huge archive of them here if you want to dive in and search.  Once you find them, I
don't know what your going to do with them as they can't be placed into your gallery, only a link I think. I tried once  for some old photos, something changed and the links were gone  poof!  ;D :D
"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

Fla._Deadheader


Ok. Why then, when I found a group of my photos, in the Archives, I looked to the left, saw "my gallery", clicked on that, and, VOILA, bunches of my photos, all with FDH, as the designation. Just that there was a "archive something" added into the photo description.

  I copied the description and posted that to Patty's thread.  I didn't want to try to move anything, even just trying to eliminate the "Archive something" embedded in the description.

  I received word a few days ago, that there is now no way to move photos around, even by trying to organize your own photos in different files, in your own Gallery.
All truth passes through three stages:
   First, it is ridiculed;
   Second, it is violently opposed; and
   Third, it is accepted as self-evident.

-- Arthur Schopenhauer (1788-1860)

SwampDonkey

Couldn't be the "old Archive" from way back. Jeff made albums on his own to categorize the archive. Unless by chance there happen to be a bunch clustered in one of his archive albums.

I don't see anything like your describing. I never did. If you click on "My Gallery", it's the new photo galleries.

You can move photos in your gallery from one of your own albums to the next. I've done it not long ago. You just can't move old photos from the old days into the new albums. When you click on a photo in an album there is an "edit file information" button or other, and within that you click on a drop down list with your album names. Just choose another one in your album list and "Apply Modifications". Done.
"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

Fla._Deadheader

 OK. Sorry to hijack yer thread, Patty.

  Swampdonkey, go to the archives in forum extras. Click on Image Archives.

  That will open the Gallery section.  Scroll down to Lumber and Wood.

  Click on Lumber and Wood 2 box.

  Now, you see the windows for crotchcypres05.jpg  and other cypress crotch stuff ???

  Click on the crotchcypres05.jpg. That brings up the new page with file1/184. See that ???

  Scroll down and click on the URL:     
https://forestryforum.com/gallery/displayimage.php?pos=-3249

  That brings up photos and MY Gallery info.  You may not see that last part, because it IS Part of MY previous Gallery, only NOT the present one on the FF. IT has LOTS of photos I knew I had posted and could not find.   THIS is where I found that 1 piece Desk photo for Patty.

  These are what I would like to combine with the new Gallery, as it were  ::) ;D :D :D
All truth passes through three stages:
   First, it is ridiculed;
   Second, it is violently opposed; and
   Third, it is accepted as self-evident.

-- Arthur Schopenhauer (1788-1860)

Don_Papenburg

Patty ,you can make a steam box out of wood .  I made a small one for steam bending plow handles .  PVC has a tendancy to sag as it is heated . Wood will warp as it dries out but it can still be used to steam other projects
Frick saw mill  '58   820 John Deere power. Diamond T trucks

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