I just started to bend ribs for my sea lancer. I am using 1/2 in white oak and steaming for 1/2 hr or so and each time the rib cracks a little. Any suggestions? Is a little cracking on the surface OK? Would soaking before steaming help? Would soaking in my hot-tub be a good idea?(I mean the ribs).
Thanks Jim
steaming wood for ribs
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TreelineIII
- Posts: 52
- Joined: Thu Mar 30, 2006 6:45 am
steaming ribs
Jim, I am going down the same path. I was hopeing to have this very discussion while attending the boat rally. What I have heard is that it is best to steam for 1hr per inch of thickness, and then add 30 minutes. I was also told to load in your steam box a few test sticks so you can test the bend on those before you crack a good rib. It is also apparently critical to use riff sawn lumber, which has the grain running long and streight the length of the rib. I have only but just built my steam box and have not yet put it to use.
Anybody with experience chime in!
Eric
Anybody with experience chime in!
Eric
steaming ribs
Well after cracking too many ribs I finally figured out that when I was bending the ribs in the boat instead of maintaining a smooth curve they were breaking off at the clamp because the wood does not like making sharp turns (right angle). Jim
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Rodney Syverson
- Posts: 43
- Joined: Tue Dec 27, 2005 4:52 pm
- Location: Ada, Minnesota
I replaced all 66 frames in my Sea Lancer. I purchased a few different books on Steam Bending wood. Danenberg's book or Fine Woodworking have got some good articles on steam bending wood. The more reading you do the better prepared you will be.
The wood should be neither green nor kiln dried. However you can bend and use kiln dried but should not use green wood. Ideally the wood should be air seasoned and needs to be clear of major knots. Tight pin knots are acceptable but not ideal in the area of the most severe bend. Soaking the boards for a day or two is a good idea. I did and I know it helps. We started in the stern which is the area of the greatest bend ( over 90 deg.). Of the 12 boards I initially steamed for that segment we ended up with 4 useable ribs. We found it best to work with two guys with one guy in the boat the other would pull the rib out of the box and start bending and hand it to myself in the boat. I would force the bottom end to the keel then bend the frame with my knee towards the hull and force it down tight. I would then set it by hammering on the top of the frame with a fairly heavy mallet. When I knew it was as tight as I could get it, it was secured with temporary screws from the underside. Of the last 14 frames we installed we used 15 out of 16 pieces from the steam box. Only one broke. However the bow frames do not require significant bending.
The most important thing to contribute to successful bending is using the straightest grain pieces you can find.
You mentioned your frames were a 1/2 inch. On my Sea Lancer I believe they were 3/4". Even on the original frames it was apparent there was some fracturing of the frames in the areas of the greatest bends I have some longtitudonal cracks that I feel don't compromise the strength but wish I had replaced with better frames. Just a matter of getting a larger number of candidates for bending so you end up with only the best. I had about 130 pieces stacked and drying for my frame run and I think when it was all done I had about 10 pieces left.
Good Luck: Rod Syverson
The wood should be neither green nor kiln dried. However you can bend and use kiln dried but should not use green wood. Ideally the wood should be air seasoned and needs to be clear of major knots. Tight pin knots are acceptable but not ideal in the area of the most severe bend. Soaking the boards for a day or two is a good idea. I did and I know it helps. We started in the stern which is the area of the greatest bend ( over 90 deg.). Of the 12 boards I initially steamed for that segment we ended up with 4 useable ribs. We found it best to work with two guys with one guy in the boat the other would pull the rib out of the box and start bending and hand it to myself in the boat. I would force the bottom end to the keel then bend the frame with my knee towards the hull and force it down tight. I would then set it by hammering on the top of the frame with a fairly heavy mallet. When I knew it was as tight as I could get it, it was secured with temporary screws from the underside. Of the last 14 frames we installed we used 15 out of 16 pieces from the steam box. Only one broke. However the bow frames do not require significant bending.
The most important thing to contribute to successful bending is using the straightest grain pieces you can find.
You mentioned your frames were a 1/2 inch. On my Sea Lancer I believe they were 3/4". Even on the original frames it was apparent there was some fracturing of the frames in the areas of the greatest bends I have some longtitudonal cracks that I feel don't compromise the strength but wish I had replaced with better frames. Just a matter of getting a larger number of candidates for bending so you end up with only the best. I had about 130 pieces stacked and drying for my frame run and I think when it was all done I had about 10 pieces left.
Good Luck: Rod Syverson
