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Thread: Pietenpol Rib Jig COMPlETE!

  1. #1

    Pietenpol Rib Jig COMPlETE!



    Finished making the rib jig today!
    I'll be making a small(ish) order of cap strips soon!
    How do you guy recommend to build a jig to bend the wood? I understand the process of wood bending but I want to make the jig for the curve set to be as simple as possible. I'll work on getting it prepared while waiting for wood.


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  2. #2
    DaleB's Avatar
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    Nice job! I used a bandsaw to cut a curved piece of 2x4, with a notch at one end to hold the end of the capstrip. Unfortunately I found I was cracking about every third or fourth piece just trying to get the bend in, even after soaking overnight. Maybe it's the cold water, I don't know. I think next I'm going to try just steaming the wood and putting it in the rib jig, we'll see how that works.

    Some guys say they don't pre-bend, they just carefully bend the wood into the jig. I can tell you, it does work, but I would rather have the wood "happy" with its new shape, if you know what I mean.

    Oh, and you may want to put another nail or two in some of those blocks. You might find the little suckers can pivot when you don't want them to.

    Where did you get the plastic? My first jig used the heavy duty polyethylene bag the plans came in, slit down one side and laid out flat. It's functional but not pretty looking. For the second one my darling wife found me some super nice, heavy duty clear vinyl at Wally World in the fabric section. Looks better (not that it's a big deal) and is less likely to get torn or cut.
    Measure twice, cut once...
    scratch head, shrug, shim to fit.

    Flying an RV-12. I am building a Fisher Celebrity, slowly.

  3. #3
    Good thinking with the extra nails. I'll have the box on standby should any of them start twisting. They're pretty solid right now so I'd rather try one out first before risking splitting the small blocks with an extra nail.
    The plastic is "Plans Protector" purchased on amazon. 25' roll and was more than wide enough. They say it should hold up but I'll be the just of that. It was holding up really well to my handling as I was nailing and moving the board around and didn't tear where the staples hold it down around the perimeter.
    For bending, I've heard that getting a 2" pvc pipe and capping one in off and using boiling water (letting the wood soak for 24 hours) does really well.
    I haven't actually done bending yet obviously but I think that's what I'm going to try.


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  4. #4
    DaleB's Avatar
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    Drill pilot holes before nailing. I used a nail with the head cut off and the clipped end filed nice and sharp, chucked in a hand drill.

    I tried using hot water in a PVC pipe, but of course when the water is hot and the garage is cold it very quickly becomes cold water. We have a steamer for clothing, I'll try that for an hour or so on the next batch and report back.
    Measure twice, cut once...
    scratch head, shrug, shim to fit.

    Flying an RV-12. I am building a Fisher Celebrity, slowly.

  5. #5
    I like the ingenuity. Thanks for the input. Let me know how that goes.


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  6. #6

    Join Date
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    A lot of woodworkers who steam use a setup like http://www.rockler.com/steam-bending...-plan-download

    If you want to build something yourself, starting with an old tea kettle like http://www.ikea.com/us/en/catalog/products/20239595/ and an inexpensive hot plate like http://www.target.com/p/oster-174-si...Q&gclsrc=aw.ds will get the job done. You might even find these for small $$ at a tag sale.

    The book on steaming wood suggests an hour at high temp for each inch of thickness.

    Best of luck,

    Wes

  7. #7
    Steam for 1 hour first. Especially with cap strips. They are thin material and wont take a lot of steam to make pliable.

    Jim

  8. #8
    bigdog's Avatar
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    Name:  2012-12-17 16.16.34sm.jpg
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    Here is the bending jig I used for some L-2 ribs. I soaked the cap strips in a tall bucket of water for about 4 hours, then clamped in the jig until dry - about 2 days. The curve of the jig was from the upper cap strip profile. I should have made the curve a little more aggressive to allow for spring back. They still worked. I just had to dry bend them a bit. Because of the spring back they were perfect for the lower cap strip. The L-2 has a 23012 semi-symmetrical airfoil with the bottom not quite the curve of the top.
    Regards,
    Greg Young
    1950 Navion N5221K
    RV-6 N6GY - first flight 5/16/2021
    1940 Rearwin Cloudster in work
    4 L-2 projects on deck

  9. #9
    Sam Buchanan's Avatar
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    Add some 1" wood dowels to your jig as clamps:

    Name:  ribjig-2.jpg
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    Drill the holes in the dowels off-center so you can rotate them and clamp the various rib components into place against the blocks. Photo above is my Legal Eagle rib jig.
    Sam Buchanan
    The RV Journal RV-6 build log
    Fokker D.VII semi-replica build log

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