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Thread: Vertical grain fir is cupping after re-sawing

  1. #16
    Join Date
    Sep 2009
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    Three Rivers, Central Oregon
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    Quote Originally Posted by Joe Calhoon View Post
    Scott, did you check the MC? All the VG I buy is KD but moisture can be anywhere from 10 to 12% and higher. And if the boards have pitch it’s hard to get a accurate reading depending on what kind of meter you use. Typically resawed 8/4 will cup. It probably will not flatten out on its own but I would definitely wait a few days and dry stack before facing and planing. If it resaws to 15/16 you can probably get 3/4 out of it. 7/8” or less 3/4 will be difficult.

    ok just re read your first post. You checked with a meter. For 6’ doors that will be difficult. Fir usually stays pretty flat after machining if the MC is balanced. 5/4 would be a better choice if available

    Joe, I was hoping to get 13/16 out of the true 1" lumber. I'm wondering if I shouldn't just upsize to 5/4 and make the doors 7/8.

    For typical kitchen cab doors, I mill rails and stiles to 3/4 x 2-3/8. For these 6' doors I'm planning 2-3/4 stiles and 3" rails including a middle rail. I've done some research but haven't found much info on rail/stile dimensioning for oversized doors. Do you have any thoughts on this? I'm planning on 3 hinges per door, Blum clip top with the adjustable cam plates. I figure I can adjust out most minor flatness issues.
    Scott Vroom

    I started with absolutely nothing. Now, thanks to years of hard work, careful planning, and perseverance, I find I still have most of it left.

  2. #17
    Join Date
    Feb 2011
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    Central WI
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    I prefer thicker frames on fir. It is lighter anyway and to me the extra heft seems to fit the wood. My experience is that reclaimed old growth is much more stable but also slivers more. New growth needs extra time in the kiln, especially for 8/4. If I have lead time I ask when the next kiln charge is part way through so the fir can be put in to finish the drying. Fir seems to hold moisture inside longer than other species but I'm no scientist so I either buy fir that doesn't need resawing or put it in the kiln. Dave

  3. #18
    Join Date
    Mar 2003
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    SE PA - Central Bucks County
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    Quote Originally Posted by scott vroom View Post
    Talked to my supplier this morning, he'll replace all the cupped lumber with KD 4/4 (or 5/4 for no up charge if he can't get 4/4)...none of it re-sawn.
    Good supplier!
    --

    The most expensive tool is the one you buy "cheaply" and often...

  4. #19
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    Dec 2008
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    Ouray Colorado
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    Scott, 5/4 is the best way to do this. You will be much happier.

  5. #20
    Join Date
    Apr 2006
    Location
    Phoenix AZ Area
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    2,505
    Until the moisture stabilizes it will move.

  6. #21
    Don't plane it!! The moisture differential needs to equilibrate or they will continue cupping.

    I have pretty decent luck putting them in stickers with the insides facing up & clamp them in battens or parallel clamps & leave them alone for a week.

    Your supplier is amazing they had no obligation to replace it.

  7. #22
    Join Date
    Sep 2009
    Location
    Three Rivers, Central Oregon
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    The boards were flat when I bought them. They cupped when I stickered them, unclamped, in my shop for a month. Next time I'll try clamping, but I'm surprised that works...I would think the the stress built up from the wet side drying would remain in the wood and after unclamping that cupping would still occur.

    Yes, my supplier is doing me a big favor. I've been a regular customer for years, but don't do anywhere near commercial volume He knows my projects are paying jobs and probably feels sorry for me . Not only did he agree to take the cupped wood back, he's brought in a unit of KD 5/4 (not re-sawn) and giving it to me at the 4/4 price.
    Scott Vroom

    I started with absolutely nothing. Now, thanks to years of hard work, careful planning, and perseverance, I find I still have most of it left.

  8. #23
    Join Date
    Sep 2009
    Location
    Three Rivers, Central Oregon
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    Here's a photo of the 2 cabinets with VGF doors/drawer fronts. Installers had just finished setting themt, GC will add the trim pieces, knobs & pulls in a few days. The 7/8" thick doors turned out near perfect flat which was a relief. Finished with 4 coats Arm-R-Seal, the first 2 coats were sponged up by the fir. Personally I would have preferred a 5th coat but the customer wanted minimal film buildup.

    The VGF was soft and easy to mill, the only issue I had was with edge splintering...it drove me nuts.

    Thanks again for the helpful advice.
    Attached Images Attached Images
    Scott Vroom

    I started with absolutely nothing. Now, thanks to years of hard work, careful planning, and perseverance, I find I still have most of it left.

  9. #24
    Join Date
    Mar 2003
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    SE PA - Central Bucks County
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    Those look REALLY good, Scott!
    --

    The most expensive tool is the one you buy "cheaply" and often...

  10. #25
    Join Date
    Mar 2014
    Location
    Los Angeles
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    Very nice work, and I have great affection for doug fir. But yes it is splintery. The edge is so fragile.

  11. #26
    Join Date
    Oct 2007
    Location
    New Hill, NC
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    2,568
    Scott, very nice work - I'm glad that things worked out in the long run.

    Your problem was almost certainly related to the wood MC%

    99% of 8/4 fir is dried for structural purposes, so it is only dried to 18%, give or take. Frequently the shell of the lumber is dried below the targeted MC% in order to help wick moisture from the core, and then the shell is rehydrated during the conditioning process. If the lumber is not conditioned then it is not uncommon for the shell to be 10% while the core is 19% (structural lumber)

    What probably happened is that the surface of the lumber was a much lower MC% than the core, and when it was resawn the newly exposed face from the core started losing moisture and shrinking.

    This is not as much of problem with properly dried hardwood lumber, because it is dried below 10%MC. It is not uncommon with structural lumber.

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