warped platter-dry wood!

All that is happening is that the wood is moving due to a gradient in relative dryness from one area to the next. That is, you are exposing wood that has been at varying distances from the previous outer edge or end of the board, thus they are at, probably very minor, differences in moisture content with the most moisture likely at the center of the board. Various areas dry at various speeds and warping results. There are also different stresses in even the cleanest og grained boards. Cutting the board alters the stresses and warping results. Rough turn the platter and let it acclimate. While I would leave a wet bowl for at least three months, a piece such as this I would leave for 48 to 72 hours. Hope it helps.

Good point as the heating season is upon us northerners. Wood's probably several points higher inside than out. He might also have shot himself in the foot if he left it "laying around" near the floor, or with one side flat on something and the other in the open air. I even stack my bowls-in-waiting on edge to make sure both sides get equal shot at the same air, even though it means much less with a bowl than a platter, where the orientation of the annual rings can exacerbate a modest moisture differential.

Normally, however, you get a warning once you get some wood removed. Things just aren't right. Time to stop and reacclimate when that happens.

You're concerned because your 10" platter warped a sixteenth of an inch ??? Doesn't seem like an awful lot of warp to me. Wood is a "living" material, in that it's moisture content continually changes. As it does, the wood continues to move. We can do what we can to minimize this movement, but we will never stop it. Platters and bowls should be uniform in thickness throughout. Whether or not that would have prevented the warp, who knows? Why don't you just enjoy your platter? No one but you will notice the 1/16" warp.

Barry

Ho-Hum! Reckon I haven't made any noises about the efficacy of the LDD treatment which stops such wood shenanigans in their/its tracks. Although, I must admit that Barry says it right in saying that 1/16 of an inch is not much movement. Has it continued to warp?

Uniform thickness is another one of those "turning" things that seems to have a life of its own. It's the species, and orientation of the annual rings which determines both direction and magnitude of distortion. Go to the Home Depot and take a look at those uniform thickness boards with their wonderful cups, bows and warps for a visual on what happens as wood adjusts.

For some good information on why.

Would LDD make any difference to kiln dried lumber? I'm sure that most of this movement is coming just from relieving stresses in the wood.

A quarter sawn board may have been a better choice. But I guess my approach, if I cared about warping, would have been to rough it out, leave it a few days, then finish turn. I might leave it a few more days before reverse turning the foot to make sure that ended up flat, being the only area that would matter to me.

I'm finding that no matter what, faceplate wood won't stay perfectly round. Whether it's green wood, kiln dried, or in between.

The explanation that makes most sense to me is that as you cut away wood, you change the distribution of internal stresses, and the wood moves to accomodate the chaange.

So, I do a rough shape turn, inside and outside of a bowl/plate. Then I go back and finish turn the outside, complete with sanding. Once I start finish cuts, I don't stop until all the sanding is completed. (No coffee break). Then I move to the inside and do the same. At this point, the outside is out of round, but it doesn't hurt the finishing process.

It's not a disaster, it's just one more thing I have to keep in mind when I do a project.

Walt C

Help for a newbie!

What's LDD?

Walt C

Thanks for all the replys. My main concern over 1/16" was that the platter now rocks. If it was just out of round, I wouldn't worry about it. It's for holding perfume bottles on a counter top, so what I'll probably do is turn and add 3 small feet in ebony or some such. I'll try quartersawn next time, or rough turn green wood and finish later.

liquid dishwashing detergent

Tsk, tsk! Buy 'em books, buy 'em books and all they do is eat the pictures!

*G*

Do what the rest of us do, even if they won't admit it. Put some sandpaper on a piece of MDO or other flat sheet goods and either drag it over the bottom where you undercut, or drag the piece over the paper.

That said, it's dollar to donuts that after doing so, it will rock on at least one of the next three places you set it.

Liquid Dish Detergent - anionic surfactants.

Action unknown, results questionable, it's supposed to keep your work from cracking up - some even say warping - if you dry it carelessly. Sort of like the current cult of ethanol users where proponents dismiss failure as due to carelessness, and attribute successful drying not to humidity control, but the soak.

Study some wood technology with R. Bruce Hoadley's _Understanding Wood_ , or download some of the excellent material at

where he worked. It will help inoculate you against anecdote and testimonial with good, scientific material. That way you can believe and support whatever you want, while hedging your bets with proven methods.

Or, he could always use a lace doily between the platter and the dresser it sits on...................Barry :-)