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Rib Bending

Discussion in 'Wood and Canvas' started by slk, Dec 9, 2018.

  1. slk

    slk Curious about Wooden Canoes

    Today was the day I started bending my ribs. I did not have the success I had hoped for. We intended to do half of the canoe. I had 13 bend successful, and broke 9. I am using white cedar that I have had in my shop for 25 years that I bought from a sawmill. It was never kiln dried but I am sure it is plenty dry none the less. I was wondering if I should soak the ribs in water first before putting them in the steam box. Any ideas are greatly appreciated....

    Steve
     
  2. Dave Osborn

    Dave Osborn LIFE MEMBER

    Yes, soak them a couple of days before you steam..
     
  3. Just1moredave

    Just1moredave Curious about Wooden Canoes

    If you soak them in a pipe vertically, you can tell how much water they have absorbed. They should initially be hard to submerge more than about halfway. You'll have to hold them down somehow. Mark the initial height and check in a couple of days to see how high they float.

    I bent 34 and the only one I broke (first one) was steamed for 30 minutes. The rest were soaked for at least a day and bent with a bending strap. I got the ribs from Island Falls as straight 60" blanks, 5/16" x2 1/4" . I don't know how they were dried.
     
  4. Dan Miller

    Dan Miller cranky canoeist Staff Member

    Soak in advance, and, very importantly, put a thermometer in your steam box. You'll have visible steam well before the steam box is up to temp. If you are not steaming your ribs at 195-210 degrees F, rethink either (or both) your steam box design or steam generator.
     
    MGC likes this.
  5. OP
    OP
    slk

    slk Curious about Wooden Canoes

    So once the box is up to temp then start timing them for the 30-45 min??????. I am using an old milk can that holds around 5 gallon's . For heat I am using one of those gas fired burners that sounds like a blow torch and will heat up stuff pretty quick. I have a thermometer I can insert in a small hole.

    I made up a bending strap for the ribs on the ends where the strongback is not there to hold them down. I would think trying to use a strap on the other ribs would slow you down if you had to keep lifting the strongback to get the strap freed up.

    I have a trough made up and I will soak the ribs before trying to steam them again. Like I said this wood has not been kiln dried, but for as long as I have had it in my shop I am sure it is close to kiln dried as you can get especially here in the winter. I have kept it in its cut dimensions all these years. 2 1/2" x 8" X 8 1/2 '

    Thanks
    Steve
     
  6. MGC

    MGC Paddlephile

    Soaking and adequate steamer time and temperature are pretty important as is making the bend quickly once the rib is removed from the box. You cannot dilly dally.
    I do not use a strap when I am bending ribs...I use one when I am bending stems.
    I have never had ribs break...unless I'm doing something boneheaded while paddling.
    Good luck...and make a few extras in case you have problems or if you ever do damage the hull...
     
  7. Dave Osborn

    Dave Osborn LIFE MEMBER

    As far as time at heat goes, the common rule is one minute for inch of thickness. Generally ribs are 5/16” thick.
    Based on that, I steam for 20 minutes.....maybe up to 30 if I lose track of time or get sidetracked.
    45 minutes could be too long and cause brittleness.
    I don’t use a strap on ribs.
    As Dan mentioned....you don’t start timing when you first see steam. It needs to get to peak heat before you time them.
     
  8. OP
    OP
    slk

    slk Curious about Wooden Canoes

    So should In wait until the box is up to temp then put the ribs in? My plan is to put about 10 of them in at a time this time. That way I won't over cook them.

    Steve
     
  9. mccloud

    mccloud Wooden Canoe Maniac

    I typically soak the rib blanks in water for 5-7 days. On steaming day I set up the box and place the kettle on an electric hotplate. This takes a long time to get the box hot, over an hour, but I feel I do not have to watch the electric hotplate the way I would a propane flame. With the box up around 200 deg.F, as measured by the meat thermometer sticking thru a small hole in the top of the box, I switch over to a burner which pushes a lot of hot steam into the box quickly raising the temp to over 200F, and at this point put in 2 wet rib blanks and steam them for 20 minutes. Don't pack the box with cedar, but rather make sure the steam can freely circulate around all surfaces. Both ribs typically will be bent over the hull within 5 minutes of coming out of the box, spring clamps along the gunwale line, and weight at the keel. Following this routine, it is rare I crack a rib. My record is about 29 in a row without cracking one. I do not use a steel compression strap for white cedar ribs. After a day or two of setting and drying, take the ribs off the hull or form, tying string at the ends to maintain the curvature, and do your final sanding and any needed trimming, i.e. rounding the top edges. Fit them into the canoe carefully, with the curved part toward the center of the canoe and working the tips up between the inwale and planking. I often add spring clamps within a couple inches of where the rib tips come up to avoid cracking the planking. All this said, there's still no substitute for practice. Tom McCloud
     
  10. OP
    OP
    slk

    slk Curious about Wooden Canoes

    When I bend my ribs I nail them to the inside gunwale right away. The ribs are already sanded and rounded over or the inside before bending. The previous canoes I have built I only broke one or two ribs per canoe. The white cedar I am using I have had for 25+ years. I am hoping hydrating them before steaming will work. Tomorrow will be the day of truth.

    Steve
     
  11. OP
    OP
    slk

    slk Curious about Wooden Canoes

    Ok guys we bent 20 ribs today without a single failure. We had the last one break and it is the one with the sharpest bend at station 1. I had a feeling they were going to work as I started pulling them out of the steam box. They felt a tad heavier to me than the ones we did earlier in the week, so soaking them was the trick. I revitalized that 25+ year old wood. They actually bent like butter with little to no effort.

    Thanks for all the replies back to me they all helped out immensely. I would post some pictures, but photobucket does not seam to work so well anymore.......

    Thanks
    Steve
     
  12. Jan Bloom

    Jan Bloom LOVES Wooden Canoes

    I have successfully bent white cedar ribs by soaking then placing them on a plastic sheet on the ground,pouring boiling water over them, covering with an old towel, more boiling water and then letting them sit for 20 minutes or so with occasional baths of boiling water. White Cedar is really easy stuff to bend.
     
  13. OP
    OP
    slk

    slk Curious about Wooden Canoes

    Well we managed to rib the rest of the canoe yesterday with no failures.

    Thanks to everyone
    Steve
     
    Dave Wermuth likes this.

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