I decided to attempt a 10" platter yesterday, starting with 3/4" kiln
dryed hard maple. Straight grained. Flatsawn. Been lying around my shop
for about 6 months aclimating. Turned the bottom about 1/4" thick and
the rim about 1/8" thick, with a curved transition between them. Used
an expansion chuck for holding both sides (drilled a 2-1/2" groove for
the first chucking on the drill press). By the time I had the inside
turned, the thing had begun to warp. By the time I sanded it, put a
sealer coat (wipe on Poly) on it and took it off the lathe, it had
warped over 1/16" "out of flat"! What happened? I have had the
experience of releasing tension in wood while ripping, but there is
usually some kind of wild grain involved. I've read here about what to
expect with wet wood, but I would have thought very dry wood wouldn't
do this. Any tips on how to avoid this in the future, or should I
expect a few disasters, chalk this up to experience and move on?

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.

--
God bless and safe turning
Darrell Feltmate
Truro, NS Canada
www.aroundthewoods.com

"Darrell Feltmate" wrote in message
news:uEXBd.29978$nN6.23963@edtnps84...
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


wrote in message
oups.com...
I decided to attempt a 10" platter yesterday, starting with 3/4" kiln
dryed hard maple. Straight grained. Flatsawn. Been lying around my shop
for about 6 months aclimating. Turned the bottom about 1/4" thick and
the rim about 1/8" thick, with a curved transition between them. Used
an expansion chuck for holding both sides (drilled a 2-1/2" groove for
the first chucking on the drill press). By the time I had the inside
turned, the thing had begun to warp. By the time I sanded it, put a
sealer coat (wipe on Poly) on it and took it off the lathe, it had
warped over 1/16" "out of flat"! What happened? I have had the
experience of releasing tension in wood while ripping, but there is
usually some kind of wild grain involved. I've read here about what to
expect with wet wood, but I would have thought very dry wood wouldn't
do this. Any tips on how to avoid this in the future, or should I
expect a few disasters, chalk this up to experience and move on?

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?

Leif
wrote in message
oups.com...
I decided to attempt a 10" platter yesterday, starting with 3/4" kiln
dryed hard maple. Straight grained. Flatsawn. Been lying around my shop
for about 6 months aclimating. Turned the bottom about 1/4" thick and
the rim about 1/8" thick, with a curved transition between them. Used
an expansion chuck for holding both sides (drilled a 2-1/2" groove for
the first chucking on the drill press). By the time I had the inside
turned, the thing had begun to warp. By the time I sanded it, put a
sealer coat (wipe on Poly) on it and took it off the lathe, it had
warped over 1/16" "out of flat"! What happened? I have had the
experience of releasing tension in wood while ripping, but there is
usually some kind of wild grain involved. I've read here about what to
expect with wet wood, but I would have thought very dry wood wouldn't
do this. Any tips on how to avoid this in the future, or should I
expect a few disasters, chalk this up to experience and move on?

"Barry N. Turner" wrote in message
...
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.

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.

http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr118.pdf For some good
information on why.

Leif Thorvaldson wrote:
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.

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.

--
Derek Andrews, woodturner

http://www.seafoamwoodturning.com
Wedding Favors ~ Artisan Crafted Gifts ~ One-of-a-Kind Woodturning

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

Bruce
"WaltC" wrote in message
oups.com...
Help for a newbie!

What's LDD?

Walt C

You could be right; however, I go with what Barry said about varying rates
of gaining/losing ambient moisture in thick or thinner parts of such a
turning, i.e., the plate. If you have time, you should do a review on all
the benefits of LDD, truly a panacea for a wood turner's woes. Good for
woodturning, too! *G*

Leif
"Derek Andrews" wrote in message
...
Leif Thorvaldson wrote:
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.

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.

--
Derek Andrews, woodturner

http://www.seafoamwoodturning.com
Wedding Favors ~ Artisan Crafted Gifts ~ One-of-a-Kind Woodturning

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

Leif
wrote in message
oups.com...
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.

wrote in message
oups.com...
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.

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.

"WaltC" wrote in message
oups.com...
Help for a newbie!

What's LDD?

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
http://www.fpl.fs.fed.us/documnts/fp.../fplgtr113.htm 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 :-)


"George" george@least wrote in message
...

wrote in message
oups.com...
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.

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.