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Thread: Cupped/Warped timber- How to unwarp?

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    Default Cupped/Warped timber- How to unwarp?

    An outline of the problem. I put aside a piece of timber from the same boards used for my transom to make a dashboard when the time came.
    Then unknown to me someone placed another piece directly on top of it on the rack without any spacers. Consequently one side only has dried out in hot dry weather and caused it to warp and cup.
    Does anyone know of a way I can get this piece back to almost straight again?

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    Default Re: Cupped/Warped timber- How to unwarp?

    You could try laying it on the grass in the sun, but keep a close eye on it. That might help with a cupped board but not a twisted one.



    Steven

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    Default Re: Cupped/Warped timber- How to unwarp?

    Cut it into narrow strips, joint each strip square, and glue them back together.
    Never trust a man with a clean workshop.

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    Default Re: Cupped/Warped timber- How to unwarp?

    What size is the cupped board? Thickness X Width X Length?

    What size do you need the dashboard to finish out at? T X W X L?
    David G
    Harbor Woodworks
    http://www.harborwoodworking.com/boat.html

    "It was a Sunday morning and Goddard gave thanks that there were still places where one could worship in temples not made by human hands." -- L. F. Herreshoff (The Compleat Cruiser)

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    Default Re: Cupped/Warped timber- How to unwarp?

    Quote Originally Posted by Mrleft8 View Post
    Cut it into narrow strips, joint each strip square, and glue them back together.
    It has a beautiful grain pattern on it that and the fact it would match the transom is why I want to keep this piece, so this would defeat the purpose.
    I'll try some of the other suggestions. Size is approx. 3/8" x 8" x 5' would like to retain as much as possible, it is for runabout and will be finished clear.
    Thanks for the tips everyone.
    Last edited by Tumzara; 09-18-2011 at 08:30 PM.

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    Default Re: Cupped/Warped timber- How to unwarp?

    If the board was already in or close to equilibrium, the crowned face will be of a higher MC than the cupped face. With a good insulated-pin meter you could check that, but regardless, the cure is placing the board crown-up in the sun for a day or two or three.

    If that doesn't fix the problem and the board is in moisture equilibrium, the next step is the jointer followed by the planer. Just keep in mind if you don't have access to a good meter that flatsawn boards cup naturally in drying, and someone stacking another board atop it may have nothing to do with why it cupped.

    Last edited by Bob Smalser; 09-18-2011 at 08:40 PM.

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    Default Re: Cupped/Warped timber- How to unwarp?

    What Mr. Bauer & Mr. Smalser said. I'd emphasize the notion that a board will continue to move - even if stacked & stickered - until it reaches equilibrium with the ambient conditions. You may be able to salvage your piece, but at only 3/8" thick by 5" wide, it's not highly likely.
    David G
    Harbor Woodworks
    http://www.harborwoodworking.com/boat.html

    "It was a Sunday morning and Goddard gave thanks that there were still places where one could worship in temples not made by human hands." -- L. F. Herreshoff (The Compleat Cruiser)

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    Default Re: Cupped/Warped timber- How to unwarp?

    Saturate it well then wrap it in black plastic and lay it out under the sun. After about 4 hours, unwrap it and lay it flat with weights to keep it flat while it dries. I've used this method with treated pine decking. Rick

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    Default Re: Cupped/Warped timber- How to unwarp?

    Thanks Bob, it is flat sawn. It is one of 3, I cut from a slightly thicker board and had no problem with the others although they were used pretty much straight away.
    I will have a go at the black plastic method first to see if I can get some of it out.
    I have been thinking that a slightly moulded shape on the instrument panel may not look that bad but having outed myself here it is public knowledge it's a stuff up.
    I'm keen to use this board as it will match the transom (the other 2 boards) which I think would look pretty smart.
    Thanks to all for your contributions.

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    Default Re: Cupped/Warped timber- How to unwarp?

    You've never said what species the wood is.
    For a dashboard that has gauges, switches, etc mounted in it, I wonder if you might not be better off with plywood, because any piece of solid wood that's thin enough to not be a pain in the neck for mounting gauges and switches will be probably prone to cracking.
    This suggests jointing the board (is it warped or cupped?) flat, then planing it down to 1/8" thickness, and gluing it to a backing of high quality plywood. That may be more stable, and easier to work with.

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    Default Re: Cupped/Warped timber- How to unwarp?

    Timber is cedar. And yes I was planning on laminating it to a plywood substrate to stabilise it.
    I had figured on gluing it to 1/4" (6mm in the modern world) and planing it down to about 12mm overall.
    I can always cut and oversize hole in the backing ply for the switches to fit if they will not go through or even look at a rebate to set the instruments and switches into.
    I haven't got that far yet as I am still working out whether I can save the board.

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    Default Re: Cupped/Warped timber- How to unwarp?

    I have read that if a veneer glued to a plywood substrate is too thick that it can come and go, and rend the veneer along the grain. The theory was that if the veneer was thinner, more like 3/32" than 1/4", then the veneer would essentially stretch, and not rend. It's a plausible theory, but I don't know if that's real.
    By the way, fractions of an inch are strictly modern, very high tech. I know this because earlier in my life we were still laying out things in spans and cubits, rods, chains and perches. And when it got down to the close work, there was always the FRCH.

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    Default Re: Cupped/Warped timber- How to unwarp?

    If you decide to laminate it to a ply substrate (especially at that thickness) you should probably laminate a similar thickness, similar species on the reverse side.
    Never trust a man with a clean workshop.

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    Default Re: Cupped/Warped timber- How to unwarp?

    Quote Originally Posted by Mrleft8 View Post
    If you decide to laminate it to a ply substrate (especially at that thickness) you should probably laminate a similar thickness, similar species on the reverse side.
    And cross all of your fingers.

    And epoxy coat the holy bejeebers out of it quickly.

    And varnish it to the nth degree.

    And be thinking about what you'll use to replace it when it splits or warps on you.

    Seriously... it might work, but you're skating right on the thinnest ice with your present scheme.
    David G
    Harbor Woodworks
    http://www.harborwoodworking.com/boat.html

    "It was a Sunday morning and Goddard gave thanks that there were still places where one could worship in temples not made by human hands." -- L. F. Herreshoff (The Compleat Cruiser)

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    Default Re: Cupped/Warped timber- How to unwarp?

    When I started to build the boat I thought it would be a bit of a novelty to use feet an inches as per drawings.
    The novelty wore off when, having decided to stretch the boat 10%, I was trying to work out the new station positions for the frames.
    Out came the calculator for a few quick conversions and forward to the 20th century I went.
    Thanks for all the input here, I will let everyone know how I go in a week or so.

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    Default Re: Cupped/Warped timber- How to unwarp?

    PS. WTF is FRCH?

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    Default Re: Cupped/Warped timber- How to unwarp?

    Quote Originally Posted by Tumzara View Post

    Out came the calculator for a few quick conversions and forward to the 20th century I went.
    Depends on what you're trying to do. In the building trades, a helluva lot more numbers divide evenly into twelve than they do ten.

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    Default Re: Cupped/Warped timber- How to unwarp?

    Quote Originally Posted by Tumzara View Post
    PS. WTF is FRCH?
    Fuzzy Red errrrrrrrrrrrrrrrrrrrrrrrrrr uuuuuummmmmmmmmmmmmm Crotch Hair
    (A very small amount. as in "It's just a little too long. Take a {FRCH} off of it...")
    Never trust a man with a clean workshop.

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    Default Re: Cupped/Warped timber- How to unwarp?

    Quote Originally Posted by Bob Smalser View Post
    Depends on what you're trying to do. In the building trades, a helluva lot more numbers divide evenly into twelve than they do ten.
    . In the USA. Everywhere else we're dividing into 1000, not 12 or 10. Rick

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    Default Re: Cupped/Warped timber- How to unwarp?

    110% of 730mm is a lot easier for me to work out than 110% of 28 & 3/4".
    Hell, it's even difficult to work out how to type it....!

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    Default Re: Cupped/Warped timber- How to unwarp?

    Quote Originally Posted by Mrleft8 View Post
    Fuzzy Red errrrrrrrrrrrrrrrrrrrrrrrrrr uuuuuummmmmmmmmmmmmm Crotch Hair
    (A very small amount. as in "It's just a little too long. Take a {FRCH} off of it...")
    Aaahh, I see. We use the metric "Bee's dick"

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    Default Re: Cupped/Warped timber- How to unwarp?

    Quote Originally Posted by RFNK View Post
    Everywhere else we're dividing into 1000, not 12 or 10.
    Fine.

    I'll build my hull to 32 feet and lay out the frames every 16 inches at 16, 32, 48, 64...etc.

    You can build the same hull to 10 meters and lay out the frames every 416.66mm. Or be even more precise and build to 9.7536 meters with frame spacings of 406.4mm. Or round it all off and build the boat to 9.744m with 406mm frame spacings. All easy to remember numbers, and easy to figure out in your head while balanced on a scaffold.

    Enjoy.
    Last edited by Bob Smalser; 09-20-2011 at 10:17 PM.

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    Default Re: Cupped/Warped timber- How to unwarp?

    Bob, I doubt that you'd be too surprised to hear that outside the USA, frame spacings etc. are arranged in line with the metric system. As far as I'm aware, even though God is clearly a US citizen, He did not ordain that boats or buildings should have dimensions dictated by the imperial measuring system. Of course I agree entirely with what I think is your point - that if you're working with a plan that's drawn in feet and inches, it's wise to use imperial measurements for the lofting and build. You might know though that, outside the US, it's also becoming very difficult to purchase materials and tools to suit the imperial system and younger people in places like Australia have no knowledge these days of the imperial system. I had a student some years ago who announced the birth of a friend's baby during a lecture by writing the Australian symbol for pound (currency, not weight) (don't have it on this computer) 8/6 Quite cheap I said - no one understood the joke at all.
    Rick

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    Default Re: Cupped/Warped timber- How to unwarp?

    In my experience, the C word in RCH is different....

    I'd try to stabilize the board to see if it is not in equilibrium, and then, when it is, plane it down to about 1/8 inch, then laminate it to the ply...
    Now is a good time!


    Steward of MAKOTO [WB Magazine #232], and Honored Member of the LPBC

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    Default Re: Cupped/Warped timber- How to unwarp?

    On the subject of the Imperial measurement system how easy is it to work out the area of a circle with a radius of 23&7/16"?
    For me I enter into a calculator 595 x 595 x 3.14 (or press the pi button).
    I know you guys are deeply attached to the system you have, (and we were too) but it seriously makes many little tasks so much more difficult with no conceivable advantage.
    But I don't want to get into an argument about measuring systems that will likely end up being "Bilge-like" in it's lack of reasonable comment.
    If you tell people what they don't wanna hear, they ain't gonna listen.

    On the subject of spacing out of frames, on the particular boat building project I am undertaking there were 2 factors involved that made the situation difficult (for me anyway) to continue to use the imperial system of measurement.
    Firstly nothing was set out in 1ft modules or even regular modules and secondly as stated I wanted to increase overall length by 10%.
    Last edited by Tumzara; 09-20-2011 at 11:25 PM.

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    Default Re: Cupped/Warped timber- How to unwarp?

    It is very easy to increase by 10% in imperial measure if you call it 120.00 inches instead of 10 feet. 10% bigger is 132 inches. inches with decimals instead of feet inches and fractions. I also find leaving it in inches instead of feet and inches causes less confusion when yelling a number to the guy cutting for me..
    would love to see how your dashboard turns out and I hope you take lots of pics of the process you end up using.
    Freudian slips : when you say one thing but mean your mother.

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    Default Re: Cupped/Warped timber- How to unwarp?

    A friend who was an engineer major at a Major Military Academy, aka "The Boat School," told me that at one point a cadre of earnest seekers after truth deployed themselves, micrometers in pocket, to the low dives and foul haunts where exotic dancers and general-purpose women of Easy Virtue were likely to be encountered, and discovered that, yes indeed, the order of fineness went: red, blonde, brown, black.
    Science marches onward.

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    Default Re: Cupped/Warped timber- How to unwarp?

    Right in the next room there's a chest of drawers which, according a friend who does furniture restoration, is almost certainly french (or done by a frenchman in the New World), probably 200-225 years old. The finish surface is tiger maple, french polish finish, hammer-veneered with hide glue onto the carcase, which is various white woods. Drawer sides pine, frame basswood. No balancing veneer on the back. The face veneer is less than 1/16" thick. Maybe it started out in 1799, or therabouts, at 1/16, and has been refinished every seventy five years or so ever since.
    In other words, veneering is an ancient art, found in Egyptian tombs, used ever since, and doesn't rely on miracle catalyzed snot to last a couple hundred years.

  29. #29
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    Default Re: Cupped/Warped timber- How to unwarp?

    Quote Originally Posted by seo View Post
    A friend who was an engineer major at a Major Military Academy, aka "The Boat School," told me that at one point a cadre of earnest seekers after truth deployed themselves, micrometers in pocket, to the low dives and foul haunts where exotic dancers and general-purpose women of Easy Virtue were likely to be encountered, and discovered that, yes indeed, the order of fineness went: red, blonde, brown, black.
    Science marches onward.
    And one would have to presume that Mr. Revlon had nothing to do with the color of the hairs in question....
    Never trust a man with a clean workshop.

  30. #30
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    Default Re: Cupped/Warped timber- How to unwarp?

    Quote Originally Posted by seo View Post
    Right in the next room there's a chest of drawers which, according a friend who does furniture restoration, is almost certainly french (or done by a frenchman in the New World), probably 200-225 years old. The finish surface is tiger maple, french polish finish, hammer-veneered with hide glue onto the carcase, which is various white woods. Drawer sides pine, frame basswood. No balancing veneer on the back. The face veneer is less than 1/16" thick. Maybe it started out in 1799, or therabouts, at 1/16, and has been refinished every seventy five years or so ever since.
    In other words, veneering is an ancient art, found in Egyptian tombs, used ever since, and doesn't rely on miracle catalyzed snot to last a couple hundred years.

    Yup... and it's a craft that requires some understanding of the proper techniques that have revealed themselves over the years. Nothing wrong with veneering at all. I've used it many times myself. If it's done incorrectly, however, it will fail. The project as initially described would fall into that category. The only way to possibly compensate for the approaches technical failings is to resort to modern day snot... and prayer.
    David G
    Harbor Woodworks
    http://www.harborwoodworking.com/boat.html

    "It was a Sunday morning and Goddard gave thanks that there were still places where one could worship in temples not made by human hands." -- L. F. Herreshoff (The Compleat Cruiser)

  31. #31
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    Default Re: Cupped/Warped timber- How to unwarp?

    Quote Originally Posted by David G View Post
    Yup... and it's a craft that requires some understanding of the proper techniques that have revealed themselves over the years. Nothing wrong with veneering at all. I've used it many times myself. If it's done incorrectly, however, it will fail. The project as initially described would fall into that category. The only way to possibly compensate for the approaches technical failings is to resort to modern day snot... and prayer.
    Not an advanced proponent of prayer so will probably give snot a try.
    A bit more background though, board was one of 3 cut from an old plank, 2 used within a month or 2 and the other left on a rack with plenty of air gap around. Seemed relatively stable until some one left another board ( which may have had moisture) lying on top of original piece. Warping was only noticed much later. Don't mind if thickness comes down until essentially a veneer but in current form curvature is greater than thickness so planing will result in missing board.
    I'll give it my best shot and may even say a prayer or 2 (nothing to lose). If it fails I'll just have to come up with plan B.

  32. #32
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    Default Re: Cupped/Warped timber- How to unwarp?

    You could also steam the thing into pliability, then let it dry while pressed/clamped flat. But, in reality, I think planing it down to a reasonable thickness veneer will serve you better. If you achieve that, it'll be pliable enough to lie flat on your substrate (plywood).
    David G
    Harbor Woodworks
    http://www.harborwoodworking.com/boat.html

    "It was a Sunday morning and Goddard gave thanks that there were still places where one could worship in temples not made by human hands." -- L. F. Herreshoff (The Compleat Cruiser)

  33. #33
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    Default Re: Cupped/Warped timber- How to unwarp?

    David G. has an interesting idea-steaming the piece to make it pliable, clamp it flat, and let it cool and set. I've never tried this, but it makes sense. I think he's also right that if you plane it down to the thickness of veneer stock that it will be pliable. My concern there would be that if the stock is severely cupped, it might crack when the feed rollers of the planer mash it flat.

  34. #34
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    Default Re: Cupped/Warped timber- How to unwarp?

    Do you really want to use cedar for a dashboard? Wouldn't the $%#^ thing just get dinged? Some kind of pseudo-mahogany would be almost as stable and gluable, and a lot more resistant to klutzy people with metal with metal objects in their hands on a boat. Get some kind person to resaw it to an eighth, plane it to a sixteenth, and use two thick, flat pieces of plywood with mylar and some weights to make an instant press. That would be my amateur solution.

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    Default Re: Cupped/Warped timber- How to unwarp?

    Why not glue the piece to plywood to stabilize it and then plane it to thickness. Especially if you are going to be planing it down really thin...
    Fish and ships or is that chips

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    Default Re: Cupped/Warped timber- How to unwarp?

    This project, and the various suggestions regarding the project, reminds me (In only the very best way, and with the fondest of memories) of a guy I had working for me back in the early '80's. David could spend hours... Entire days sometimes, trying to figure out how to make a 1/2 hour job easier. He's still a good friend, but he didn't last long on the job.
    Never trust a man with a clean workshop.

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    Default Re: Cupped/Warped timber- How to unwarp?

    Quote Originally Posted by StevenBauer View Post
    You could try laying it on the grass in the sun, but keep a close eye on it. That might help with a cupped board but not a twisted one.



    Steven
    ^ what he said

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