Twisted Table Slide  

Probably best and easiest would be to replace it with a new piece. That's pretty severe twist or "wind" (rhymes with "find" and is considered a defect) in the board and it would take a lot of steam and force to torture it back into plane with no guarantee of permanence. Any local cabinet shop or handyman could make a new one easily enough.

If you weren't all the way out in Chi-Town, I'd tell you to send it over and I'll turn it around in a day.

@tktoo2  Thanks again for the reply - helpful as always.  With nothing to lose, I went ahead and tried to straighten it by wrapping in a wet towel and placing 20lb dumbbells on it.  After a couple of days it was pretty straight, so I applied a couple coats of shellac in hopes of sealing it in place.  Well, as you predicted, it is slowly reverting to it's former twisted state, though after a week it's still straighter than it was before, as this current picture shows.  I don't know if it will keep twisting but it's straight enough to do its job for now.  I've been planning to take a woodworking class so hopefully I can make a replacement slide if needed.      

@mark737, Good for you for trying! And good for you for considering taking a woodworking course, but I must warn you. There's more to learn than possible in one lifetime. My only advice is to learn how to use and maintain hand tools. You can make almost anything out of wood without using any electricity, making loud noise, or throwing toxic dust everywhere.

Edit: Oh, if you buy only one book on the subject, I highly recommend "The Encyclopedia of Furniture Making" by Ernest Joyce, Patrick Spielman, and edited by Alan Peters. Out of the hundred or so books and manuals on shelves in my workshop, it's the only one not covered in a layer of sawdust. Buy a newer used edition online for short money. Invaluable, IMO.

The warping is caused by internal stress in the grain structure of the piece and typically gets worse as it dries out over time. Often, this condition is predictable and better furniture makers reject these pieces as defective. Some species can be permanently bent to varying degrees by heating with steam and forcing and clamping into shape until cool, but even those will "spring back" somewhat over time if unrestrained. Though sealing the piece might help in the short term, there's no coating that will effectively prevent wood from eventually achieving equilibrium.

@tktoo2  Thanks for the book recommendation, I will pick up a copy.  I'd been thinking about picking up a table saw since so many estate sales in my area have them - seems like everyone with a garage back in the 50's-70's owned one.  But I like the idea of doing as much as possible with hand tools.  Oh, and by the way, I'm only in the Chicago time zone, I'm actually down in Texas.   

@mark737, Don't get me wrong, I love my power tools, too, and using them is the only way I can make any money in my workshop. A table saw is a common, and good, first major power tool purchase for those starting out(mine, too). Definitely restrict your search to good-quality, belt-driven saws that take 10-inch blades with a 5/8"diameter arbor and at least 1 1/2HP- 120V motors. Older Delta "Contractor's" saws that haven't been worn out and/or abused pop up for $300 and under frequently enough around here.  Hobbyist-owned saws are what I'd watch for on craigslist and such. The small portable saws just aren't up to precision work and aren't designed to be adjustable or repaired.

I think your DA profile says Chicago, FYI. I've only ever been to Texas once, down Corpus way. What I remember most, besides armadillo road-kill, were the occasional gas stations with big signs advertising ICE ...BEER ...AMMO.

@tktoo2  DA profile options are country and time zone.  I'm in Central Texas but plenty of armadillos, beer and ammo here too.