Replies

1. 
   BruceS | Jan 29, 2011 07:54pm | #1

   What kind of glue ?  And what kind of gluing process ?  I'm thinking a moisture problem from the glue and uneven drying.

2. 
   SteveSchoene | Jan 29, 2011 08:56pm | #2

   You have two problems with the construction.  First, the 1/4" thickness of the squares is too much for it to act as a veneer. Try 1/8" thickness, it would have worked much better.  Consequently, when the squares changes moisture content they will  have enough shrink/swell to cause the plywood to curl.  Secondly, the squares aren't  balanced on each side of the plywood.  Veneer applied on one side often results in a potato chip shape.  Hopefully, the base you plane to attach this too will be beefy enough to resist the twist. 

1. 
   musashi | Jan 29, 2011 09:28pm | #3

   The base, unfortunately, has openings for drawers for the chess pieces, and for shelves for the captured pieces while playing.  It is not beefy enough to pull things back. 

   I will put it all together, with plans for someday making another top. 

   So if I made the squares 1/8" thick, and covered the bottom of the substrate with 1/8"  thick veneer, that would do the trick.  Right?

   Thanks for the input.

   Alex

   
3. 
   roc | Jan 29, 2011 09:44pm | #4

   I have learned to allow time for these little learning detours

   Fun huh ?

   I wonder what would happen if you kerfed the underside?  One direction or both.  The Festool hand held plunge circular saw would be ideal.  Then, if that works, add a thin board to the back of that with minimal glue.  Epoxy, maybe, so no moisture.

   If no room for the thin board perhaps fill in the kerfs with epoxy and filler/fiber stuff they make just for that.

   At lest it's an excuse to buy the Festool if you don't already have one.

   PS:  I enjoy looking at the combination of the wood you chose.

1. 
   musashi | Jan 30, 2011 08:31am | #5

   I have thought about kerfing the back.  Since the top has a very small overhang over the apron, hiding the kerfs would not be much of an an issue - they would go to within 3/4" of the edge of the tabletop. 

   I couldn't really add a thin board, since my edging is already on... unless I routed for it, but that starts to get to be a bit much. 

   Thanks for the comment on the wood.  Many years ago I made a maple and mahogany china hutch.  When my 9-year-old son and I sat down to design the chess table, he told me that we had to use the same woods. 

   Alex

4. 
   RalphBarker | Jan 31, 2011 11:30am | #6

   material selection

   Yep, most of the HD ply comes pre-warped. ;-)

1. 
   musashi | Feb 01, 2011 06:14am | #7

   Yeah, I guess we all sell our soul, little by little, for the sake of convenience.

5. 
   JerryW | Feb 06, 2011 08:34pm | #8

   While the previous poster's

   While the previous posters' comments are all sound, I believe that your fundamental construction problem was that you ran the grain direction in all of the squares the same.  Hence, you have a glued up , 1/4"piece of wood with only one grain direction.  Had you alternated the grain direction of each square, t(vertical/horizontal/...) the top would act essentlially like a non-directional plywood sheet.  Now the solid wood top is expanding/contracting on top of an immovable plywood sheet - hence the bowing.

   Jerry

6. 
   musashi | Feb 23, 2011 09:15pm | #9

   Hello everybody:

   On the tablesaw, I just kerfed the underside of the table top.  There are about 40 kerfs under there, with about a 1/4" space between them. 

   With a block down the middle and some clamps on the ends, I can pull out the warp, but it will return when I release the pressure.  I am thinking of either filling the kerfs with epoxy (kind of expensive by the time I buy enough tubes), or polyurethane construction adhesive.  (The kind in a caulking gun tube - it dries hard as a rock and does not let go.) 

   Are there any compelling reasons why the polyurethane construction glue would not be good?  For example, moisture issues, stains bleeding through, etc.

   Plan B is to cut a piece of 1/4" ply, and epoxy it over the kerfs, all, within the area that is inside the apron, so it won't be seen. 

   Comments?

   Thanks.

   Alex

1. 
   Westchester | Feb 24, 2011 07:29am | #10

   Next Step

   Musashi,

   Don't know the glue you're thinking of using ( polyurethane construction adhesive) but does it expand as it cures ?

   SA

2. 
   acornw | Feb 25, 2011 10:04am | #11

   Simple Solution

   The solution is to make the top with balanced construction: equal thickness and species of veneer on both sides, running the same direction, as previously stated.  Glue it up flat, with all components acclimatized together.

   If you don't, there will be problems.  This is a very old situation, with a very simple, equally old solution, and a history almost as long of people trying to fix it other than doing it correctly.  None of the fixes work well.  You will not be able to overcome this basic force of Nature.

1. 
   AutumnWoods | Feb 25, 2011 10:22am | #12

   Try this...

   Since you have the maple border on already why not relieve a 1/4" rabbet around the base, add a 1/4" piece of veneer to the bottom, and use epoxy in the glue up so you can spread it on thick and fill the saw kerfs.  Run the grain across the direction of the warp to help lend it strength.  I don't know if this will work with your base design but at least it would keep you from having to redo the edging.  Best of luck!

1. 
   musashi | Feb 26, 2011 09:36pm | #13

   This afternoon I used lots of epoxy and glued on a piece of 1/4" ply, grain running across the direction of the warp. 

   Fingers crossed.  Will take it out of clamps tomorrow night.

   Alex