Warped Table Leaf

[Dale Stillman]

Just completing a large dinning room table for a cust. The leaf size is 24" x 36". I have completed the finish on this w/the exception of the 2 final coats of 'table top' & the finish buffing. Now I find that the leaf has warped. It is approx. 1/2" higher in the center. When glueing this up I did alternate the grain pattern. What to do? Can I spring it back into shape by weighting the center? The outside edges are 1-1/2" thick by 5" wide x 24". The inside board is panel 3/4" thick x 26" wide x 24". Panel made up of 6 boards glude together. TIA for the help. Can always make a new leaf but feel that is the last choice.

[Bob Boake]

Other than surface planing or some other mechanical means, I have never had any luck with what you are wanting to do. Sometimes wood can move because it was dried improperly. Sometimes it seems to move for no good reason whatsoever. Even if you could flatten the board in a press I would be afraid that the crown would return.

[Jim Becker]

Did you apply your finish to BOTH sides of those leaves? What you describe is sometimes a symptom of only finishing one side of such an object. Unlike the rest of the table top, the leaves really don't have anything binding them into place, although finish should be on the bottom of them, too. The warping from this issue is a combination of unequal moisture containment and tension from the finish drying.

[David Rose]

finishing the other side will likely *very* slowly allow it to stabilize. If you can use some retension method on the table, I would likely try to flatten it by moisture application and weighting. If you don't have a way to retain it on the table, it will likely warp back.

David

[Gene Hatcher]

I refinished a maple table for my oldest son when he married and bought a house a year ago. The table was over 50 years old and the top was gull-winged when viewed from either end. I applied six coats of varnish to both sides and rubbed it out after a month long cure. Three months later the top was flat. The underside of the top had never been finished. So, sometimes that works. Put the same number of coats of finish on both sides.

[Carl Eyman]

My understanding of steam bending is that it is the temperature not the moisture that makes wood bend more easily. I've never tried this, but what about building a steam box that will hold the leaf, steam it 3 hours, and hold it in a frame with a slight reverse bend to it. Let it cool sown and see what "God Hath Wrot". If it works, please let me know. I built my granddaughter an armoire and one of the doors has this problem. I would have tried the solution many years ago, but she never closes the doors anyway.

[Jerry Solomon]

A method that is shown in a book I have calls for placing the concave side downward in your yard (on damp grass) and then placing one or more heavy objects on the top. They say to let it sit in the sun for anywhere from a few hours to several days. The idea is to introduce water into the concave side. I have straightened a couple of leaves this way.

[Tom Gattiker]

I have put water on boards for days to eliminate cup. Amazing how it flattens out BUT the cup comes back when the water evaporates. Just my experience.

[David Rose]

moisture uptake, this might work. If the board was laid flat on the bench right after milling and then cupped or whatever, added moisture and weight might even things out.

If the iregularity comes from case hardening or other internal stresses, the treatment shouldn't last. Then again, possibly the stresses could be effected by doing this.

I had some figured maple panels that were cut from years old air dried wood. You could watch the stuff change as it was resawed then again as it was planed. I added moisture to some and clamped them flat with space to allow for evaporation. After leaving them for a few weeks then unclamping some returned to their original shape, some warped in another direction and a couple stayed fairly flat.

Moisture does seem to change some internal structure in wood. I just don't think it is predictable enough to count on. Being a hobbiest with more time than money, I usually give it a try before giving up.

David

[Tom Gattiker]

thanks for sharing it.