laminating oak fames

Discussion in 'Wooden Boat Building and Restoration' started by sawdusty, Apr 8, 2007.

  1. sawdusty
    Joined: Apr 2007
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    Location: conneticut

    sawdusty New Member

    Hello all,

    This is my first post so bare with a newbie. A few years ago I bought a breathtaking 36' sloop built in 1939 by Hubert Johnson and designed by Frederic Geiger. She is desperate need of many new frames. I have decided upon laminating new ones out of white oak (matching original design species).I have ample supply of white oak available at several local saw mills. My question is how long should the oak season before working with it?

    Thanks,
    Sawdusty
     
  2. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    You'll likely have to steam the frames, even thin pieces to make them conform to the turn of the bilge and possibly some reverse curves at the bow and stern. For this you'll want as green of stock as you can get, which will steam the best and air dry very quickly as thin milled stock.
     
  3. Bergalia
    Joined: Aug 2005
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    Bergalia Senior Member

    laminating oak frames

    You can't improve on Par's advice. It's spot on.
     
  4. lazeyjack

    lazeyjack Guest

    My Grandad used to say, oak never ever stops moving But we used American White, for the interior finish of that yacht you see in my gallery, all the joinerwork has stayed tight, but we machined some stair stringers from into 12 inch x 1 inch and boy did they ever cup, Not that you will be worried abt this, , white oak is immensely strong though, if you have a wine glass shape section you will have to do as the guys said, BUT if you have not or that part is taken up by the cut of the floors, then you could laminate dry quite easily, after they are glued up they won't shift at all can you post a sectional? would tell you for sure
    you can cut a pattern from rubbish sheet material like cheap 3/4 ply, then you can chock your laminations to that! Ok now start workin while we watch
    oh dont ferget your bevels:))
     
  5. sawdusty
    Joined: Apr 2007
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    sawdusty New Member

    Thanks

    Thank you all for your great advice. Probably a dumb question, but.. should I steam and shape in a jig, then laminate and install as one piece?

    Would it be better to forgo the lamination idea and replace with solid frames?

    Does anyone have any great designs for a temporary shelter to construct over this project?

    Thanks
     
  6. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    I find it easier to make solid frames, but laminated is just as good.

    You can laminate them in place, using planking, bands, stringers, etc. as the form or make bending molds so you can do them on a table then install them after dry.

    Installing them in the boat requires a few people, quick moves and sure hands, with all the tools you'll need to manhandle the beasts into place in just a couple of minutes. I don't recommend it for the first time builder, replacing some frames. It just requires too much coordination and timing to get them in, squared to their location, firm against the planking, clamped and fastened, with the very short working window you typically have on steamed stock, which is literally just a couple of minutes.

    Bending them over a mold requires a template be made of each frame. Some times you can employ one mold, with slight modification, across a few frames, but this also requires some experience.

    In most cases, when a boat needs new frames, it also needs new stem and stern post, deadwood repairs, floor repair/replacement, stringer, etc. As a result of this, the boat has lost it's shape and installing new frames to the old boat means you'll provide a nice firm structure to a distorted hull.

    When I replace frames, I'll have jacked, twisted, cursed and generally moved the old hull back into proper position, eliminating any hog, bilge sag, deck spread, etc. This way you will be repairing a boat that is correctly shaped. That last boat I did this on was a 25' lapstrake power cruiser. It was pretty badly distorted, partly from damage and some from age and trailer life. It took the better part of 10 months to slowly jack, pull twist and talk her back into the shape she used to have. If I hadn't done this, the boat would have performed very poorly, as she developed a bad "hook" from her butt hanging on a poorly fitted trailer. This hook would have likely prevented this boat getting up on plane.

    The stern was jacked back up, over a course of 4 months an eighth of an inch at a time, then secured with temporary bracing, inside and out to hold her there. The stem had sagged, developing a hog (drooping ends) which was also jacked back up at the same time, using the boat weight as leverage against the ends. The bilges had relaxed and the deck spread, but not real bad, though a bit lopsided, so she had to be twisted and pulled together along the sheer and jacked along the turn of the bilge. In the end I had to repair the keel on this boat to fully restore the run aft, which is it's planning surface to get it right again.

    I've done both, laminate on a mold and also in place, both have advantages and disadvantages. Each boat is different, access and disassembly usually dictate what you'll be able to do. Finding the room to manipulate steamed frame slices into the boat can be a challenge to say the least. The template/mold approach is a more sure method for the amateur. Yep, it's more work, making templates, building a mold for each frame, but it's also more accurate and easier to work in a down hand position rather then contorting to the confines found in the belly of the beast.

    A simple tent is about the easiest method to cover a project, but it's just a cover. Hoops of wood, PVC tubing, steel or aluminum pipe can be formed to go completely over the boat. I work in Florida so I'll just place two poles, one at each end of the boat, both much taller then the height of the boat. I'll string a fairly heavy line taunt from each pole, down the centerline of the boat, then toss a tarp over the whole mess (I used a 40' x 20' tarp on the 25' cruiser). I prop up the tarp when working on it and let it cover it completely when not. Weights on the tarps edges will keep it in place (water filled milk jugs work good).
     
  7. lazeyjack

    lazeyjack Guest

    as I said.first make an accurate pattern Then draw the shape on something you can clamp or screw to . Screw wooden blocks to the that and cut little wooden wedges so you can wedge the lamintions in There is no need to steam, I have made wide oak curved steps from 10inch wide stuff, Experiment with quarter inch thick, you may even get to 5/16 use water mixed glue I will try find the name, they build moulded wood hulls with this glue cos it sets very quickly is super strong and of coarse waterproof, In half an hr you can lift the frame!!
     
  8. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    Epoxy does not work with oak. The acids in it will break the glue. You need resorcinol.
     
  9. lazeyjack

    lazeyjack Guest

    Do you know this?? for sure? becuae I take great care to ONLY write stuff I have years of experience with At 60 years old I dont write stuff to be noticed, but to be of help
    look here, 6 years on all holding up , much glued in Epoxy, joinerwork in that yellow one pack stuff,
    But the stuff I was impressed with you mix with water, , one pack powder
     

    Attached Files:

  10. lazeyjack

    lazeyjack Guest

    and those laminated steps there take 100kg men running up and down them 24x7
     
  11. gonzo
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    gonzo Senior Member

    Those are not structural members. The epoxy manufacturers agree that it shouldn't be used with oak unless it is cabinetry or just cosmetic parts.
     

  12. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    I've had some successes using epoxy on white oak, but only in thin laminations, where the tannins have been removed just prior to applying the epoxy. I don't recommend laminates more then 3/8" thick, with 1/4" being my personal limit. Resorcinol and Plastic Resin adhesives do work well, but also require perfect joints and lots of clamping pressure. Because these glues don't have gap filling properties, the joints have to mate dead on, which isn't a problem for most craftsman. Finding sufficient clamping pressure (or locations to put a clamp) while performing repairs onboard can be challenging.

    For the most part, Gonzo is correct about white oak and epoxy, in structural applications.
     
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