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  • #4188

    I have recently just fabricated a bunch of 1 1/4″ thick solid walnut table tops.  The planks I used were 5″ to 6″ wide and were glued together (using Titebond 2).  We cut the blanks to size and then ran them through the surface sander.  We took them to the finish shop and put a coat of stain on them.  After we let the stain dry over the weekend, we came in today and noticed that many of them have separated at the joints.  The separation travels in about 2 to 3 inches and is as wide as an 1/8″ in some spots.  Any thoughts as to what would cause this?  Is my finish shop to dry?  Why did it only travel in a a couple inches?  What can I do in the future to prevent this?  What can be done with to save the tables that were close to done?

    #57815
    KCWOOD
    Member

    jjdjr1    First of all, the 5-6″ wide is a little wide for walnut, to be gluing up.  My first question is, is it kiln dried lumber and if so, was it taken down to 6-1/2% moisture content? But if it was moisture.. you would be asking about warpage.

    If is was KD, you should be fine with that. 
    Next… when you dry fitted the wood before glue up, were the joints so good, it looked like a solid board. If you had to tighten clamps, even just a little, to pull the joint together, this is your problem.  Walnut is actually a pretty stable wood.

    My guess is this based on my 30+ years of woodworking. You did not have straight tight joints from the start. Glueup was made with the comment.. “yeah that will pull up”. 

    Did you run each edge through the jointer before glue-up? Did you alternate the grain, up/down?

    Let me know about the dry fit…and the size of your panels,  and I can get you to the next easy step…

    KC

    #57839
    Wags
    Member

    I agree with Kelsey, the width was my first red flag. As he said alternating the grain (up and down) is critical. We handle Craft Art Wood tops, theirs are almost always in the range of 3″ wide. When you ran then through the sander, did you make sure to remove all sanding dust, to allow the adhesive to grab?

    #57841
    Tom M
    Member

    KC, isn’t walnut a particularly oily wood? Would that make a difference?

    #57850
    David Gerard
    Member

    water borne stain?

    #57852
    KCWOOD
    Member

    David, yep…  and Tom no… walnut works great.

    Reading what wags wrote, I noticed I mis-read the post. Blanks were run through the sander.  I have never been able to run anyhting through my wide-belt to where I would get a glue-edge flatness.

    Pictures would be great. I have glued up 10’s of thousands of panels, and I never had a joint fail that I was aware of. It should be the strongest point after glue-up.

    #57868
    Andy Graves
    Keymaster

    I do not work with wood much, but would biscuits help ?

    #57873
    Steve Mehan
    Member

    jjdrj, Is your finish shop & your shop in the same building or different location?
    What part of the country are you in?
    How was the stain applied and what type of stain was used?
    Stain Walnut????
    To much clamp pressure?
    We have fabricated many BB tops and are working on both a Walnut &  Cherry tops currently. What I have found is in my part of the country the Northeast during the winter months the humidity is very low and people are also heating there homes, this has a tendancy to dry the wood more and can cause the joints to split if the wood has not been finished and is unstable. We dont let any unfinished layup sit for more then a day in these very dry conditions.
    Titebond II is a very strong glue and I have also used it for the same applications you have and what I have found is that sometimes the boards may split before the joints do. Has this happened to every table or just to one? Also is the spliting occuring on every joint?

    #58091
    Steve Mehan
    Member

    Here are a few pic’s of the walnut and cherry jobs we were working on both tops are glued up with titebond III, the board width’s are typically 1.5″ – 2″.
    The cherry top is used a a penninsula with a small section against a wall with a cove splash and the walnut is an island top.

    #58097
    Dani Homrich
    Member

    Made the same mistake some 33 years ago on a 8′ top. 5″ wide Walnut is OK if it is fabricated correctly. My first flag was doing the edges on a surface sander and not a Jointer. Second The boards MUST fit perfect with out any clamp presser, if you have to clamp the strips to pull them together they will separate. The mistake I made years ago was thinking that an 1/8″ space in some of the joints that could be pulled together with clamps would be ok not the case. The fix was to cut the tops apart at the joints run them through a Jointer and redo. With light clamping presser you should not be able to slip a sheet of paper in any of the joints.

    #58098
    Andy Graves
    Keymaster

    Nice looking tops Steve. Is the cove wood countertops taking off for you?

    #58113
    Steve Mehan
    Member

    Andy,
    Most of the wood BB tops we do people like the idea of the cove for all the same reasons that SS customers do.I like doing them and the cove is a nice upsell. It,s strange they kinda go in spurts. We’ve had a few jobs recently for butcher block but also alot of interest in laminates.

    #58259
    Eli Polite
    Member

    i agree with all the only thing i would add is sometimes letting the wood acclimate to the environment it is going to be in helps as well

    #59686
    Paul Bingham
    Member

    We have glued up thousands of panels for dining room tables, buffet/hutches and doors for many years in walnut, oak, birch, maple, ash, cherry, etc.. Jointing on a good jointer is essential to good joints.

    The most important thing to achieving long term success with solid wood glueups is finishing both sides equally with the same finish material.  Without the same finish on both sides (usually the bottom gets none or little) the wood will warp across the panel as one side or other is always taking on or releasing moisture at a different rate than the other. Drying wood to a particular moisture content is the correct way to start, but the wood will always be changing moisture content from winter to summer in most climate areas. In the winter most houses are bone dry and in the summer get very humid in the summer.

    We used to make dining tables of solid wood up to 108″ long with two large end panels and three removable leaves. We had to be very carefull how we constructed them as the wood grain was across the table. We started with wood kilned to 6%, but by the time the wood travels thru several wharehouses and several months or more of sitting stacked in lifts and our shop the moisture usually was at around 8%. After a year or three in clients homes we measured the tables for total length on several occassions and found the tables would shrink up to 1″ in the middle of winter and expand by the same amount in late summer. Of course we had to make table supports and skirts that could accomodate this movement or we would have had to spend a lot of time repairing tables. This is a movement of about 1% overall. This is typical for most woods.

    It is possible to calculate wood movement by wood type, grain orientation and moisture content.

    A kitchen top will be even more affected because of the environment. Proper sealing on both sides will be essential to the long term success of the tops.

    Paul

    #59693

    Posted By Paul Bingham on 11 May 2010 06:21 AM
    The most important thing to achieving long term success with solid wood glueups is finishing both sides equally with the same finish material.  Without the same finish on both sides (usually the bottom gets none or little) the wood will warp across the panel as one side or other is always taking on or releasing moisture at a different rate than the other.
    Paul

    Paul:

    Bob Flexner, a wood finish writer and teacher for eighteen years, disagrees in “Finish Both Sides? Not Necessary”.

    I’m not paying the $1.99 to make his point, but I got this much for free:

    “Finishing both sides isn’t necessary. Leaving the underside of your tabletop bare doesn’t cause warping.”

    Joe

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