For now this is just curiosity; I haven't got a specific project in mind.
If you build a table top from solid wood boards and you want to cover
the end grain with other (narrower) boards running perpendicular to the
"field" boards, how do you fasten the ends?
I think I get that you can't attach them rigidly, but how do you allow
for some play without there being obvious play? Tenons on the ends of
the main slats with extra length in the mortise on the ends? Then just
screwed in on the bottom in oversized holes?
On Jun 5, 5:30=A0pm, -MIKE- <[email protected]> wrote:
> On 6/5/13 10:10 AM, Greg Guarino wrote:
>
> > Does the amount of movement depend at all on the type and thickness of
> > finish? To take an extreme example, what about those thick resin
> > finishes you sometimes see on bar and restaurant tables?
>
> Look underneath those tables. =A0 :-)
>
Fair enough. But I think there must be more to it than that. If
sufficient sealing eliminated the problem, people would do it,
wouldn't they?
On Jun 4, 1:58=A0pm, Greg Guarino <[email protected]> wrote:
> For now this is just curiosity; I haven't got a specific project in mind.
>
> If you build a table top from solid wood boards and you want to cover
> the end grain with other (narrower) boards running perpendicular to the
> "field" boards, how do you fasten the ends?
Try this for a starter:
http://www.finewoodworking.com/how-to/article/all-about-breadboard-ends.asp=
x
Breadboarding is no deep, arcane method ....
Greg Guarino <[email protected]> wrote:
> On Jun 5, 11:08 pm, Leon <lcb11211@swbelldotnet> wrote:
>> On 6/5/2013 8:30 PM, Greg Guarino wrote:
>>
>>> On Jun 5, 5:30 pm, -MIKE- <[email protected]> wrote:
>>>> On 6/5/13 10:10 AM, Greg Guarino wrote:
>>
>>>>> Does the amount of movement depend at all on the type and thickness of
>>>>> finish? To take an extreme example, what about those thick resin
>>>>> finishes you sometimes see on bar and restaurant tables?
>>
>>>> Look underneath those tables. :-)
>>
>>> Fair enough. But I think there must be more to it than that. If
>>> sufficient sealing eliminated the problem, people would do it,
>>> wouldn't they?
>>
>> You are not going to stop movement, a good finish will simply reduce the
>> amount if you spill a glass of water in the joint.
>
> Again, I would be the last to argue that I know something the rest of
> you don't. I'm just curious about the *why* of it. The answer, as best
> I can tell, is that wood finishes simply do not actually seal the wood
> against moisture entering or escaping.
That and as I stated earlier, everything chances shape with temperature
changes. Most wood has a moisture content in the 6~12% range. Finishing the
wood does not remove that moisture.
"Mike Marlow" <[email protected]> writes:
>Larry W wrote:
>
>>>
>> Easy enough to test if you want to.
>>
>> Take a scrap board of the same type of wood you're going to use,
>> finish it the way you're planning, and measure it when dry (maybe
>> heat it at 100 d Far. in an oven or something) then again when it's
>> good and humid. (Maybe keep put it in the bathroom for a few days
>> when you family is taking hot showers) Measure it and scale up for
>> the width of your table.
>
>I worded my comment/question rather poorly. Quite poorly in fact. I was
>doing more of what I would call mental wandering than anything else, in my
>comment.
>
>I'm very aware of wood movement, as I get to watch it every change in
>seasons. We have wood floors in our house that are on average, around 15"
>wide. The gaps between the boards shrink and grow in a very visible way
>every year as we move from rather humid spring/fall/summer to very dry
>(woodstove) winter weather. So - even if I was inclined to argue "in
>theory", I couldn't, based on observation. These boards though are only
>sealed on the top. My doors on the other hand, are sealed on all surfaces,
>and exposed to the same conditions, only absorb or lose moisture at a
>fraction of the rate the floors do, and move very little. Again - easy to
>verify by viewing the margins, etc. Admitedly, the amount of movement that
>you might consider negligible in a door - or even not enough to see, might
>well be very noticible in another application like a table top.
Comparing movement in a floor, where all the boards are parallel and
growth and shrinkage is all in the same direction (across the grain),
to a door, where the boards are arranged in a fashion designed to
reduce or eliminate movement across with width of the door (the panels
may expand/contract within the frame bounded by the rails and the stiles
but neither the rails nor the stiles will change in length, thus you
won't see any changes at the margins. Apples != Oranges.
scott
On Jun 6, 8:42=A0am, Leon <[email protected]> wrote:
> Greg Guarino <[email protected]> wrote:
> > On Jun 5, 11:08 pm, Leon <lcb11211@swbelldotnet> wrote:
> >> On 6/5/2013 8:30 PM, Greg Guarino wrote:
>
> >>> On Jun 5, 5:30 pm, -MIKE- <[email protected]> wrote:
> >>>> On 6/5/13 10:10 AM, Greg Guarino wrote:
>
> >>>>> Does the amount of movement depend at all on the type and thickness=
of
> >>>>> finish? To take an extreme example, what about those thick resin
> >>>>> finishes you sometimes see on bar and restaurant tables?
>
> >>>> Look underneath those tables. =A0 :-)
>
> >>> Fair enough. But I think there must be more to it than that. If
> >>> sufficient sealing eliminated the problem, people would do it,
> >>> wouldn't they?
>
> >> You are not going to stop movement, a good finish will simply reduce t=
he
> >> amount if you spill a glass of water in the joint.
>
> > Again, I would be the last to argue that I know something the rest of
> > you don't. I'm just curious about the *why* of it. The answer, as best
> > I can tell, is that wood finishes simply do not actually seal the wood
> > against moisture entering or escaping.
>
> That and as I stated earlier, everything chances shape with temperature
> changes. Most wood has a moisture content in the 6~12% range. Finishing t=
he
> wood does not remove that moisture.
I was under the impression that the most important factor is the
change in moisture content rather than the absolute amount. That's why
I wondered why "sealing" the wood doesn't work. Apparently the answer
is that "sealing" does not in fact prevent all moisture migration in
and out.
On 6/6/2013 1:58 PM, Greg Guarino wrote:
> I was under the impression that the most important factor is the
> change in moisture content rather than the absolute amount. That's why
> I wondered why "sealing" the wood doesn't work. Apparently the answer
> is that "sealing" does not in fact prevent all moisture migration in
> and out.
Correct .. a finish will only slow down the process, but will NOT
prevent the process.
The key factor in a wood reaching and EMC (equilibrium moisture content)
is RH (relative humidity) of its environment.
Some things to note:
1. Wood does not shrink or swell in use unless its MC changes. Read this
again, as it is so important. Wood's MC changes when the RH around the
wood changes. Of course, if the wood is at the wrong MC when first put
into use, it will adjust to achieve equilibrium with its environment and
therefore may shrink or swell initially quite a bit.
2. Another key point is that the MC of lumber, as well as shop
conditions, should be such that the wood, from lumber to finished goods,
will change less than 2 percent MC after drying, in storage, in
manufacturing and when put into service.
Here's a handy download:
http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr190/chapter_13.pdf
And another treatise on moisture content of wood in use:
http://www.fpl.fs.fed.us/documnts/fplrn/fplrn226.pdf
That entire Forest Products Laboratory is a gold mine of wood related
information for both construction and furniture uses.
--
eWoodShop: www.eWoodShop.com
Wood Shop: www.e-WoodShop.net
https://plus.google.com/114902129577517371552/posts
http://www.custommade.com/by/ewoodshop/
KarlCaillouet@ (the obvious)
> ... The problem is, with a solid wood table top of any significant
> width, the change in width with humidity & the seasons means that for
> much of the time the breadboard ends will be either longer or shorter
> than the width of the table. ....
You can avoid this by making the ends a bit longer than the table's
width and rounding over the ends. I've seen this particularly in some
Arts and Crafts furniture.
On 6/6/2013 5:36 PM, Larry W wrote:
> In article <[email protected]>,
> Mike Marlow <[email protected]> wrote:
>> Edward A. Falk wrote:
>>> In article <[email protected]>,
>>> Greg Guarino <[email protected]> wrote:
>>>> On 6/4/2013 6:03 PM, Larry W wrote:
>>>>
>>>>
>>>> I've been wondering about this. How does the moisture get in and out
>>>> of the (finished) wood? Is the finish more permeable that I think it
>>>> is?
>>>
>>> Yep. All finishes are permeable; even the thickest layer of
>>> polyurethane will let moisture in and out.
>>
>> Yeahbut - how much? Enough to cause movement? How much movement? This is
>> more than just a rhetorical question - I'm really questioning that thought.
>> Not because I necessarily disagree, but because it does not seem to me that
>> if the wood is fully sealed, it will absorb enough moisture to amount to a
>> hill of beans.
>>
>> --
>>
> Easy enough to test if you want to.
>
> Take a scrap board of the same type of wood you're going to use, finish
> it the way you're planning, and measure it when dry (maybe heat it at
> 100 d Far. in an oven or something) then again when it's good and humid.
> (Maybe keep put it in the bathroom for a few days when you family is
> taking hot showers) Measure it and scale up for the width of your table.
>
And take into consideration that the scrap of wood is not going to
move enough to cause a problem. A wide table top however could move in
excess of 1/8". So multiply the movement measurement accordingly.
On 6/7/2013 4:24 PM, Larry W wrote:
> In article <[email protected]>,
> Leon <lcb11211@swbelldotnet> wrote:
>> On 6/6/2013 5:36 PM, Larry W wrote:
>>> In article <[email protected]>,
>>> Mike Marlow <[email protected]> wrote:
>>>> Edward A. Falk wrote:
>>>>> In article <[email protected]>,
>>>>> Greg Guarino <[email protected]> wrote:
>>>>>> On 6/4/2013 6:03 PM, Larry W wrote:
>>>>>>
>>>>>>
>>>>>> I've been wondering about this. How does the moisture get in and out
>>>>>> of the (finished) wood? Is the finish more permeable that I think it
>>>>>> is?
>>>>>
>>>>> Yep. All finishes are permeable; even the thickest layer of
>>>>> polyurethane will let moisture in and out.
>>>>
>>>> Yeahbut - how much? Enough to cause movement? How much movement? This is
>>>> more than just a rhetorical question - I'm really questioning that thought.
>>>> Not because I necessarily disagree, but because it does not seem to me that
>>>> if the wood is fully sealed, it will absorb enough moisture to amount to a
>>>> hill of beans.
>>>>
>>>> --
>>>>
>>> Easy enough to test if you want to.
>>>
>>> Take a scrap board of the same type of wood you're going to use, finish
>>> it the way you're planning, and measure it when dry (maybe heat it at
>>> 100 d Far. in an oven or something) then again when it's good and humid.
>>> (Maybe keep put it in the bathroom for a few days when you family is
>>> taking hot showers) Measure it and scale up for the width of your table.
>>>
>> And take into consideration that the scrap of wood is not going to
>> move enough to cause a problem. A wide table top however could move in
>> excess of 1/8". So multiply the movement measurement accordingly.
>
> Uh, that's what "scale up" means.
>
Oh yeah, Doh!
On 6/5/2013 8:30 PM, Greg Guarino wrote:
> On Jun 5, 5:30 pm, -MIKE- <[email protected]> wrote:
>> On 6/5/13 10:10 AM, Greg Guarino wrote:
>>
>>> Does the amount of movement depend at all on the type and thickness of
>>> finish? To take an extreme example, what about those thick resin
>>> finishes you sometimes see on bar and restaurant tables?
>>
>> Look underneath those tables. :-)
>>
>
> Fair enough. But I think there must be more to it than that. If
> sufficient sealing eliminated the problem, people would do it,
> wouldn't they?
>
You are not going to stop movement, a good finish will simply reduce the
amount if you spill a glass of water in the joint.
On 6/12/2013 9:08 AM, Leon wrote:
> On 6/12/2013 5:56 AM, Swingman wrote:
>
>
> Where are you at now?
Still in AR, Hot Springs now ... up to my alligator in another bath
remodel ... this one is sweat equity for Blondie.
No rest for the elderly.
--
eWoodShop: www.eWoodShop.com
Wood Shop: www.e-WoodShop.net
https://plus.google.com/114902129577517371552/posts
http://www.custommade.com/by/ewoodshop/
KarlCaillouet@ (the obvious)
On 6/4/2013 12:58 PM, Greg Guarino wrote:
> For now this is just curiosity; I haven't got a specific project in mind.
>
> If you build a table top from solid wood boards and you want to cover
> the end grain with other (narrower) boards running perpendicular to the
> "field" boards, how do you fasten the ends?
>
> I think I get that you can't attach them rigidly, but how do you allow
> for some play without there being obvious play? Tenons on the ends of
> the main slats with extra length in the mortise on the ends? Then just
> screwed in on the bottom in oversized holes?
Bread board ends.
Cut a tenon on the ends of the table, The solid bread board end piece
has a mortise to fit the tenon on the end of the table top. Typically
the end is placed on the table end and 3~5 holes are drilled through the
bread board end and through the tenon. Remove the bread board end and
elongate all but the center hole on the tenons to allow for table top
expansion and contraction. Replace the bread board end and glue dowels
in the holes. The center dowel with the tight fit will keep the end
centered. The other dowels will keep the end from coming off the table
top but will allow expansion and contraction movement.
I can provide a sletchup drawing if that will be helpful.
Seriously though properly sanded the plain end grain does not look bad
and is a lot less trouble. With the other you are always going to get
movement and at any given time the bread board end is not going to be
flush with the side of the table.
On Jun 5, 11:08=A0pm, Leon <lcb11211@swbelldotnet> wrote:
> On 6/5/2013 8:30 PM, Greg Guarino wrote:
>
> > On Jun 5, 5:30 pm, -MIKE- <[email protected]> wrote:
> >> On 6/5/13 10:10 AM, Greg Guarino wrote:
>
> >>> Does the amount of movement depend at all on the type and thickness o=
f
> >>> finish? To take an extreme example, what about those thick resin
> >>> finishes you sometimes see on bar and restaurant tables?
>
> >> Look underneath those tables. =A0 :-)
>
> > Fair enough. But I think there must be more to it than that. If
> > sufficient sealing eliminated the problem, people would do it,
> > wouldn't they?
>
> You are not going to stop movement, a good finish will simply reduce the
> amount if you spill a glass of water in the joint.
Again, I would be the last to argue that I know something the rest of
you don't. I'm just curious about the *why* of it. The answer, as best
I can tell, is that wood finishes simply do not actually seal the wood
against moisture entering or escaping.
On 6/6/2013 1:58 PM, Greg Guarino wrote:
> On Jun 6, 8:42 am, Leon <[email protected]> wrote:
>> Greg Guarino <[email protected]> wrote:
>>> On Jun 5, 11:08 pm, Leon <lcb11211@swbelldotnet> wrote:
>>>> On 6/5/2013 8:30 PM, Greg Guarino wrote:
>>
>>>>> On Jun 5, 5:30 pm, -MIKE- <[email protected]> wrote:
>>>>>> On 6/5/13 10:10 AM, Greg Guarino wrote:
>>
>>>>>>> Does the amount of movement depend at all on the type and thickness of
>>>>>>> finish? To take an extreme example, what about those thick resin
>>>>>>> finishes you sometimes see on bar and restaurant tables?
>>
>>>>>> Look underneath those tables. :-)
>>
>>>>> Fair enough. But I think there must be more to it than that. If
>>>>> sufficient sealing eliminated the problem, people would do it,
>>>>> wouldn't they?
>>
>>>> You are not going to stop movement, a good finish will simply reduce the
>>>> amount if you spill a glass of water in the joint.
>>
>>> Again, I would be the last to argue that I know something the rest of
>>> you don't. I'm just curious about the *why* of it. The answer, as best
>>> I can tell, is that wood finishes simply do not actually seal the wood
>>> against moisture entering or escaping.
>>
>> That and as I stated earlier, everything chances shape with temperature
>> changes. Most wood has a moisture content in the 6~12% range. Finishing the
>> wood does not remove that moisture.
>
> I was under the impression that the most important factor is the
> change in moisture content rather than the absolute amount. That's why
> I wondered why "sealing" the wood doesn't work. Apparently the answer
> is that "sealing" does not in fact prevent all moisture migration in
> and out.
>
Sealing helps to reduce the amount of absorption and drying out but
there is still moisture in the wood that will react to temperature
change. Not nearly as much but there will always be change and the
reason that you must always allow for wood movement.
On 6/4/13 1:35 PM, Leon wrote:
> Seriously though properly sanded the plain end grain does not look bad
> and is a lot less trouble.
I agree. I might add it is very difficult to get any table top with wide
boards to NOT split in one or more places. The big fad, now, in
restaurant decor is to have these glued up, fat panel tables with the
thickly poured epoxy top finish. I have yet to see one that didn't have
splits within a year.
There is probably a right way to do it without splits, but these mass
producers aren't doing it.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
In article <[email protected]>,
Greg Guarino <[email protected]> wrote:
>For now this is just curiosity; I haven't got a specific project in mind.
>
>If you build a table top from solid wood boards and you want to cover
>the end grain with other (narrower) boards running perpendicular to the
>"field" boards, how do you fasten the ends?
>
>I think I get that you can't attach them rigidly, but how do you allow
>for some play without there being obvious play? Tenons on the ends of
>the main slats with extra length in the mortise on the ends? Then just
>screwed in on the bottom in oversized holes?
Google "fastening breadboard ends" and you'll find a multitude of ways
to do this. The problem is, with a solid wood table top of any significant
width, the change in width with humidity & the seasons means that for
much of the time the breadboard ends will be either longer or shorter
than the width of the table. IMHO it is better to leave the exposed
end grain showing. (On a plywood top, this is not an issue, plywood does
not expand/contract the way solid wood does, and the breadboard ends or
edge banding can be rigidly fastened.)
--
There is always an easy solution to every human problem -- neat,
plausible, and wrong." (H L Mencken)
Larry W. - Baltimore Maryland - lwasserm(a)sdf. lonestar. org
On 6/4/2013 6:03 PM, Larry W wrote:
> The problem is, with a solid wood table top of any significant
> width, the change in width with humidity & the seasons means that for
> much of the time the breadboard ends will be either longer or shorter
> than the width of the table.
I've been wondering about this. How does the moisture get in and out of
the (finished) wood? Is the finish more permeable that I think it is?
Does the amount of movement depend at all on the type and thickness of
finish? To take an extreme example, what about those thick resin
finishes you sometimes see on bar and restaurant tables?
I'm not arguing here, I'm just curious about the process.
Swingman <[email protected]> wrote:
> On 6/12/2013 9:08 AM, Leon wrote:
>> On 6/12/2013 5:56 AM, Swingman wrote:
>>
>>
>> Where are you at now?
>
> Still in AR, Hot Springs now ... up to my alligator in another bath
> remodel ... this one is sweat equity for Blondie.
>
> No rest for the elderly.
The enlarged downstairs bath? That one is looking good as far as the
layout is concerned.
In article <[email protected]>,
Greg Guarino <[email protected]> wrote:
>On 6/4/2013 6:03 PM, Larry W wrote:
>
>
>I've been wondering about this. How does the moisture get in and out of
>the (finished) wood? Is the finish more permeable that I think it is?
Yep. All finishes are permeable; even the thickest layer of polyurethane
will let moisture in and out.
--
-Ed Falk, [email protected]
http://thespamdiaries.blogspot.com/
On 6/5/13 10:10 AM, Greg Guarino wrote:
> Does the amount of movement depend at all on the type and thickness of
> finish? To take an extreme example, what about those thick resin
> finishes you sometimes see on bar and restaurant tables?
>
Look underneath those tables. :-)
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
-MIKE- wrote:
> On 6/5/13 10:10 AM, Greg Guarino wrote:
>> Does the amount of movement depend at all on the type and thickness
>> of finish? To take an extreme example, what about those thick resin
>> finishes you sometimes see on bar and restaurant tables?
>>
>
> Look underneath those tables. :-)
Bingo!
--
-Mike-
[email protected]
Edward A. Falk wrote:
> In article <[email protected]>,
> Greg Guarino <[email protected]> wrote:
>> On 6/4/2013 6:03 PM, Larry W wrote:
>>
>>
>> I've been wondering about this. How does the moisture get in and out
>> of the (finished) wood? Is the finish more permeable that I think it
>> is?
>
> Yep. All finishes are permeable; even the thickest layer of
> polyurethane will let moisture in and out.
Yeahbut - how much? Enough to cause movement? How much movement? This is
more than just a rhetorical question - I'm really questioning that thought.
Not because I necessarily disagree, but because it does not seem to me that
if the wood is fully sealed, it will absorb enough moisture to amount to a
hill of beans.
--
-Mike-
[email protected]
On 6/5/13 8:30 PM, Greg Guarino wrote:
> On Jun 5, 5:30 pm, -MIKE- <[email protected]> wrote:
>> On 6/5/13 10:10 AM, Greg Guarino wrote:
>>
>>> Does the amount of movement depend at all on the type and thickness of
>>> finish? To take an extreme example, what about those thick resin
>>> finishes you sometimes see on bar and restaurant tables?
>>
>> Look underneath those tables. :-)
>>
>
> Fair enough. But I think there must be more to it than that. If
> sufficient sealing eliminated the problem, people would do it,
> wouldn't they?
>
As other have said, perhaps there is no sealing sufficient enough to
stop movement.
If there was a top coat that stopped expansion and contraction of wood,
we'd surely see raised panel doors that were made without floating
panels. We don't.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
In article <[email protected]>,
Mike Marlow <[email protected]> wrote:
>Edward A. Falk wrote:
>> In article <[email protected]>,
>> Greg Guarino <[email protected]> wrote:
>>> On 6/4/2013 6:03 PM, Larry W wrote:
>>>
>>>
>>> I've been wondering about this. How does the moisture get in and out
>>> of the (finished) wood? Is the finish more permeable that I think it
>>> is?
>>
>> Yep. All finishes are permeable; even the thickest layer of
>> polyurethane will let moisture in and out.
>
>Yeahbut - how much? Enough to cause movement? How much movement? This is
>more than just a rhetorical question - I'm really questioning that thought.
>Not because I necessarily disagree, but because it does not seem to me that
>if the wood is fully sealed, it will absorb enough moisture to amount to a
>hill of beans.
>
>--
>
Easy enough to test if you want to.
Take a scrap board of the same type of wood you're going to use, finish
it the way you're planning, and measure it when dry (maybe heat it at
100 d Far. in an oven or something) then again when it's good and humid.
(Maybe keep put it in the bathroom for a few days when you family is
taking hot showers) Measure it and scale up for the width of your table.
--
The best argument against democracy is a five-minute conversation
with the average voter. (Winston Churchill)
Larry W. - Baltimore Maryland - lwasserm(a)sdf. lonestar. org
Larry W wrote:
>>
> Easy enough to test if you want to.
>
> Take a scrap board of the same type of wood you're going to use,
> finish it the way you're planning, and measure it when dry (maybe
> heat it at 100 d Far. in an oven or something) then again when it's
> good and humid. (Maybe keep put it in the bathroom for a few days
> when you family is taking hot showers) Measure it and scale up for
> the width of your table.
I worded my comment/question rather poorly. Quite poorly in fact. I was
doing more of what I would call mental wandering than anything else, in my
comment.
I'm very aware of wood movement, as I get to watch it every change in
seasons. We have wood floors in our house that are on average, around 15"
wide. The gaps between the boards shrink and grow in a very visible way
every year as we move from rather humid spring/fall/summer to very dry
(woodstove) winter weather. So - even if I was inclined to argue "in
theory", I couldn't, based on observation. These boards though are only
sealed on the top. My doors on the other hand, are sealed on all surfaces,
and exposed to the same conditions, only absorb or lose moisture at a
fraction of the rate the floors do, and move very little. Again - easy to
verify by viewing the margins, etc. Admitedly, the amount of movement that
you might consider negligible in a door - or even not enough to see, might
well be very noticible in another application like a table top.
--
-Mike-
[email protected]
Scott Lurndal wrote:
> "Mike Marlow" <[email protected]> writes:
>> Larry W wrote:
>>
>>>>
>>> Easy enough to test if you want to.
>>>
>>> Take a scrap board of the same type of wood you're going to use,
>>> finish it the way you're planning, and measure it when dry (maybe
>>> heat it at 100 d Far. in an oven or something) then again when it's
>>> good and humid. (Maybe keep put it in the bathroom for a few days
>>> when you family is taking hot showers) Measure it and scale up for
>>> the width of your table.
>>
>> I worded my comment/question rather poorly. Quite poorly in fact.
>> I was doing more of what I would call mental wandering than anything
>> else, in my comment.
>>
>> I'm very aware of wood movement, as I get to watch it every change in
>> seasons. We have wood floors in our house that are on average,
>> around 15" wide. The gaps between the boards shrink and grow in a
>> very visible way every year as we move from rather humid
>> spring/fall/summer to very dry (woodstove) winter weather. So -
>> even if I was inclined to argue "in theory", I couldn't, based on
>> observation. These boards though are only sealed on the top. My
>> doors on the other hand, are sealed on all surfaces, and exposed to
>> the same conditions, only absorb or lose moisture at a fraction of
>> the rate the floors do, and move very little. Again - easy to
>> verify by viewing the margins, etc. Admitedly, the amount of
>> movement that you might consider negligible in a door - or even not
>> enough to see, might well be very noticible in another application
>> like a table top.
>
> Comparing movement in a floor, where all the boards are parallel and
> growth and shrinkage is all in the same direction (across the grain),
> to a door, where the boards are arranged in a fashion designed to
> reduce or eliminate movement across with width of the door (the panels
> may expand/contract within the frame bounded by the rails and the
> stiles but neither the rails nor the stiles will change in length,
> thus you won't see any changes at the margins. Apples != Oranges.
>
> scott
Point well taken. That's why I included the escape clause in my previous
post (last sentence).
--
-Mike-
[email protected]
In article <[email protected]>,
Leon <lcb11211@swbelldotnet> wrote:
>On 6/6/2013 5:36 PM, Larry W wrote:
>> In article <[email protected]>,
>> Mike Marlow <[email protected]> wrote:
>>> Edward A. Falk wrote:
>>>> In article <[email protected]>,
>>>> Greg Guarino <[email protected]> wrote:
>>>>> On 6/4/2013 6:03 PM, Larry W wrote:
>>>>>
>>>>>
>>>>> I've been wondering about this. How does the moisture get in and out
>>>>> of the (finished) wood? Is the finish more permeable that I think it
>>>>> is?
>>>>
>>>> Yep. All finishes are permeable; even the thickest layer of
>>>> polyurethane will let moisture in and out.
>>>
>>> Yeahbut - how much? Enough to cause movement? How much movement? This is
>>> more than just a rhetorical question - I'm really questioning that thought.
>>> Not because I necessarily disagree, but because it does not seem to me that
>>> if the wood is fully sealed, it will absorb enough moisture to amount to a
>>> hill of beans.
>>>
>>> --
>>>
>> Easy enough to test if you want to.
>>
>> Take a scrap board of the same type of wood you're going to use, finish
>> it the way you're planning, and measure it when dry (maybe heat it at
>> 100 d Far. in an oven or something) then again when it's good and humid.
>> (Maybe keep put it in the bathroom for a few days when you family is
>> taking hot showers) Measure it and scale up for the width of your table.
>>
> And take into consideration that the scrap of wood is not going to
>move enough to cause a problem. A wide table top however could move in
>excess of 1/8". So multiply the movement measurement accordingly.
Uh, that's what "scale up" means.
--
Make it as simple as possible, but not simpler. (Albert Einstein)
Larry W. - Baltimore Maryland - lwasserm(a)sdf. lonestar. org
On 6/6/2013 8:09 AM, Greg Guarino wrote:
> Again, I would be the last to argue that I know something the rest of
> you don't. I'm just curious about the *why* of it. The answer, as best
> I can tell, is that wood finishes simply do not actually seal the wood
> against moisture entering or escaping.
Even if they did, there is still temperature.
dadiOH
On 6/5/2013 10:10 AM, Greg Guarino wrote:
> On 6/4/2013 6:03 PM, Larry W wrote:
>
>> The problem is, with a solid wood table top of any significant
>> width, the change in width with humidity & the seasons means that for
>> much of the time the breadboard ends will be either longer or shorter
>> than the width of the table.
>
> I've been wondering about this. How does the moisture get in and out of
> the (finished) wood? Is the finish more permeable that I think it is?
> Does the amount of movement depend at all on the type and thickness of
> finish? To take an extreme example, what about those thick resin
> finishes you sometimes see on bar and restaurant tables?
>
> I'm not arguing here, I'm just curious about the process.
>
You never get all the moisture out. Atmospheric conditions such a
pressure and temperature can cause the wood to move.
Many of the thick resin finishes have some give, they are pliable.