Replies

1. 
   ErnieConover | May 27, 2006 03:48pm | #1

   The first matter of business is to figure out why the top cracked? Generally cracked tops are because the top was not attached to the underlying frame so as to allow for wood movement. In a book I once did on tables, I photographed a friend's table which was doweled to a trestle frame. A myriad of cracks and checks which fluctuated with the season was the result. If wood movement is the problem you have to deal with this first. There are many good schemes for attaching table tops to allow for wood movement.

   If it is a delaminating of the glue line the edges were not jointed well enough in the first place. A glue joint loses strength by a power of three as the gap increases. (Doubling a glue gap reduces the strength by a factor of 8.) This is why a good fit is necessary and waney glue joints are always problematic.

   Some of the repairs I have seen over the years:

   1. Remove the top saw through the check / glue separation, joint the resulting edges(this time straight and true) and re-glue. You are virtually making the top over.

   2. If the check or glue separation is at the end you can sometimes carefully backsaw out a thing wedge and put a matching wedge of the same wood in and plane/sand everything out level.

   2. In the middle of a table you can use various fillers ranging from shellac (melted in) to epoxy mixed with wood dust. For small checks this fix can be pretty good.

   3. If the check is only in the top side you can chisel a patch out of the bottom side of the table, under the problem. Chisel a like depression over the check and glue the patch in place. This is very skilled work but not that hard to do once you have done it a time or two. The advantage is that you replace the damaged area with wood of much the same grain and color. It is good for large damage such as hot irons left on table tops, etc.

   4. Fill the check and veneer the whole surface obeying all of the veneer rules. (Both sides have to be veneered.)

   All of these repairs are labor intensive and require a good deal of finishing and touch up skill. It is often as easy to make an entirely new top. It happens to most workers once or twice and usually gives the extra incentive to make sure the wood is properly dry, that you cut back far enough from checked ends in boards and that you joint all edges properly.

   With best regards,
   Ernie Conover