Replies

1. 
   oldusty | Dec 16, 2007 06:27pm | #1

    Hi Kingsun ,

                  How was this wood dried ?

                   What is the moisture content out side and inside % ?

                      Did you surface the panel stock prior to glue up ?

         I really think the RH factor is changing and the wood is not stable so fast .

                 dusty

                    

2. 
   HowardAcheson | Dec 16, 2007 07:20pm | #2

   >> Two 6 inch wide boards that were left on the table developed cupping, bowing, and warping overnight

   One thing you should never do is leave boards flat on something else. This prevents air from freely getting to both sides. If the boards are not fully acclimated to the shop, the exposed side with absorb or emit moisture causing an imbalance in moisture content which causes warping.

   The same thing with panels you have glued up. Never store them flat on a table or other solid surface. The panels will warp. Either sticker them or store them standed straight up and down with air space between them. Don't store them against the interior of an outside cement or brick wall. Moisture comes right through cement and brick and will again cause uneven moisture on each side of the panel.

   The good news is that, if caught quickly, boards or panels that have warped from improper storage can generally be salvaged by stickering them and weighting them so air can get to both sides.

   Howie.........
1. 
   kingsun | Dec 17, 2007 02:07am | #3

   Both of you make good points. The history of this birch lumber is as follows. I bought about 200 bf at a surplus auction 4 years ago. The lumber was from a large local wholesale/commercial specialty yard here in the Kansas City area, so I assume it had been kiln dried. When I bought it (for an admittedly low price of less than 50 cents per bf) I noticed a lot of the boards were bowed and warped. It was all S2S and ran about 0.8 to 0.9 inches. In the ensuing years, the lumber was first stored in my unheated garage and then in an unheated but weather-tight wood storage shed. I plead guilty to probably rushing the time between bringing pieces into my shop and then planing and cutting to rough dimensions. But the question still haunting me is whether birch that has been appropriately dried and acclimated is a stable material for panel glue-ups. The lumber I have was being turned into flat doors for a "Euro"-style set of cabinets. Should I shun birch for future similar projects? It is relatively cheap around here, but it ain't really so cheap when I have to start all over again. Thanks for your input

1. 
   ted | Dec 17, 2007 02:13am | #4

   My guess ids that it hasn't had long enough to acclimate to the indoors. I've used a lot of flame Birch over the years and while I may get a board here and there that does that won't behave most of it has been fairly stable and I haven't had problems such as you describe when I've handled the material properly.

1. 
   kingsun | Dec 17, 2007 02:56am | #5

   I'm happy to hear that. I have another 100 bf of flame birch bought a couple of years ago from a one-man sawmill in Minnesota (for a lot more than 50 cents per bf). I will move it into the shop for a month or so before milling. Thanks

1. 
   ted | Dec 17, 2007 05:40pm | #6

   Just read your other post about using the Birch for flat panel doors. That is one use I'd reconsider. My experience with flat slab type doors hasn'r been exactly successful. The interior of the cabinet doen's get the same air movement as the exterior and you end up with doors tweaked in all directions. You'd be better off veneering panels for the doors.

2. 
   HowardAcheson | Dec 17, 2007 06:47pm | #7

   >> But the question still haunting me is whether birch that has been appropriately dried and acclimated is a stable material for panel glue-ups.Wood is only stable when the relative humidity in which it finds inself is un-changing. Whether kiln dried or air dried, wood will absorb or emit moisture to come to the equilibrium moisture content consistant with the relative humidity.That said, birch is a frequently used furniture wood and is certainly suitable for that use. I have built a number of items where I used birch panels.Howie.........

3. 
   joinerswork | Dec 19, 2007 06:45pm | #16

   king,

   I wonder if your major problem is that you bought a bunch of stock that had already been "culled" by the previous owner as sub-par.  Maybe the wood came from a tree that was all reaction wood, growing out of a riverbank, was poorly treated in the kiln, whatever.  The fact that much of it was badly warped from the get-go is a clue. If I  end up with stuff like that, it's a good idea to use it for as small projects as possible.  Rough sizing and leaving it lay for a while never hurts either.

   Ray

3. 
   frenchy | Dec 17, 2007 09:07pm | #8

   kingsun

     Sorry to come late to the dance, but the troubles you indicate of cupping and such isn't typical of birch which seems pretty well behaved..

     My experience with hardwoods warns me that hickory will split if you look at it mean Elm will twist, bow, dance the hootchie cootchie, and in general behaves like a juvenile delinquent.  Maple will rot if, well maple will rot if you don't handle it perfectly and flash dry it. That produces it's own problems such as case hardening.  But Birch in general if it's really dry is stable and well behaved. 

     Yours sounds like it's not dry yet.. what does your moisture meter say? surface and interior.   Did you sticker the wood and strap it or weight it?   What sort of air movement did you have?  was it exposed to UV light during the drying process? 

1. 
   JohnWW | Dec 17, 2007 10:53pm | #9

   Frenchy,

   The question about UV light threw me, I've never heard of light exposure affecting wood stability, does it? 

   Your basic analysis is probably correct, the wood wasn't acclimated to the shop when he started working on it.

   John W.

1. 
   frenchy | Dec 17, 2007 11:00pm | #10

   John.

    That's my short cut way of asking about it's exposure to weather.. I have lost boards when I don't cover them and rain and rapid heating from sunlite caused them to warp even when properly strapped in place..

1. 
   JohnWW | Dec 17, 2007 11:14pm | #11

   That makes sense now.

   John W.

1. 
   frenchy | Dec 18, 2007 12:20am | #13

   john,

    I sometimes get myself in trouble because of typing..

    (I'm lousy at it because I'm dyslexic and have to hunt every time for where my brain moved that letter too)   so I take shortcuts and frequently get called on them which causes me to type longer posts to not have to re-explain things. which then makes me take more short cuts which calls me back etc..

4. 
   Glaucon | Dec 17, 2007 11:39pm | #12

   I agree with the previous comments that acclimation is important. I would also add that milling and stickering is likely key for success with your remaining birch. I would acclimate for ~6 weeks. I would then rough mill (joint and first pass thicknessing) and sticker the wood for 7-10 days before doing a final milling to size. When you do the second milling, consider chalking one surface before re-jointing to make certain that you are evenly remilling, then do your final thicknessing passes through the planer. Resticker for 2-3 days.

   This seems like a lot of trouble, but it will give you your best shot at good results. If this solves your problem, you might be able to abridge the process going forward. If you notice very little wood movement after the first milling, you could contract the time of the final milling. Good luck.

   Glaucon

   If you don't think too good, then don't think too much...

1. 
   kingsun | Dec 19, 2007 03:19am | #14

   Thanks to all for your comments. It certainly sounds like I need to use more care in getting birch (and other) lumber to be happy in its new shop home. This helps me rethink my approach to what I hope someday can be a business. Longterm storage of lumber in the shop environment needs to be factored in. I knew this, but it's sooooo easy to get in a rush. This has been a very painful and costly reminder that planning ahead is a smart thing to do.

1. 
   KiddervilleAcres | Dec 19, 2007 04:47pm | #15

   I want to thank you for posting this discussion.  I learned a great deal from it.  Cherry and birch are my favorite woods to work with.  I would guess that just about everything discussed would apply for any wood.

   My take is let it acclimate to the woodshop environment for milling to final dimensions.  Apply the finish to protect it from its eventual home environment.

   Regards,Bob @ Kidderville Acres

    

   A Woodworkers mind should be the sharpest tool in the shop!