I am making a cover from teak to cover the mantle on my fireplace. The
current mantle is really ugly piece of blue stone. The teak will match a
teak entertainment center I built a year ago. The mantle will be covered on
all sides. The mantle is 74 1/2". This is in a vacation home in New
Hampshire. It will be down to about 55 degrees in the winter and maybe 80
degrees and humid in the summer.

OK, that was the long slow windup. Here comes the pitch. How much room would
you leave for expansion? The side pieces will match up to some trim where
the chimney and the wall meet so I can't just make it as wide as I want.

Your advice would be greatly appreciated.

Dick Snyder

"Dick Snyder" wrote:

I am making a cover from teak to cover the mantle on my fireplace. The
current mantle is really ugly piece of blue stone. The teak will match a
teak entertainment center I built a year ago. The mantle will be covered on
all sides. The mantle is 74 1/2". This is in a vacation home in New
Hampshire. It will be down to about 55 degrees in the winter and maybe 80
degrees and humid in the summer.

OK, that was the long slow windup. Here comes the pitch. How much room would
you leave for expansion? The side pieces will match up to some trim where
the chimney and the wall meet so I can't just make it as wide as I want.

Your advice would be greatly appreciated.

Dick Snyder


Not enough information. Look at
http://www.woodworkerssource.com/movement.php

For how to estimate
--
Alex -- Replace "nospam" with "mail" to reply by email. Checked infrequently.

On 10/25/2012 3:10 PM, Dick Snyder wrote:
I am making a cover from teak to cover the mantle on my fireplace. The
current mantle is really ugly piece of blue stone. The teak will match a
teak entertainment center I built a year ago. The mantle will be covered on
all sides. The mantle is 74 1/2". This is in a vacation home in New
Hampshire. It will be down to about 55 degrees in the winter and maybe 80
degrees and humid in the summer.

OK, that was the long slow windup. Here comes the pitch. How much room would
you leave for expansion? The side pieces will match up to some trim where
the chimney and the wall meet so I can't just make it as wide as I want.

Your advice would be greatly appreciated.

Dick Snyder




Relative no length expansion and or thickness expansion. The only
expansion that you will notice will be in solid board widths. Leave
yourself a bit of wiggle for the boards to expand and contract in width.
On a 12" wide board I would suggest as much as 1/4" wiggle room. This
may not be an issue if the width/edges of the board are not between two
fixes surfaces. If one edge is not confined there should be no issue.

"Leon" lcb11211@swbelldotnet wrote in message
...
On 10/25/2012 3:10 PM, Dick Snyder wrote:
I am making a cover from teak to cover the mantle on my fireplace. The
current mantle is really ugly piece of blue stone. The teak will match a
teak entertainment center I built a year ago. The mantle will be covered
on
all sides. The mantle is 74 1/2". This is in a vacation home in New
Hampshire. It will be down to about 55 degrees in the winter and maybe 80
degrees and humid in the summer.

OK, that was the long slow windup. Here comes the pitch. How much room
would
you leave for expansion? The side pieces will match up to some trim where
the chimney and the wall meet so I can't just make it as wide as I want.

Your advice would be greatly appreciated.

Dick Snyder




Relative no length expansion and or thickness expansion. The only
expansion that you will notice will be in solid board widths. Leave
yourself a bit of wiggle for the boards to expand and contract in width.
On a 12" wide board I would suggest as much as 1/4" wiggle room. This may
not be an issue if the width/edges of the board are not between two fixes
surfaces. If one edge is not confined there should be no issue.

Thanks. The widest board will be 7" x 74 1/2". I was most worred about
length but I do have room on width as long at I place the two end pieces,
which will be at a 90 degree angle to the long boards, with screws in
oversized holes so the long pieces can move.

On Thu, 25 Oct 2012 18:30:48 -0400, Dick Snyder wrote:

Thanks. The widest board will be 7" x 74 1/2". I was most worred about
length but I do have room on width as long at I place the two end
pieces, which will be at a 90 degree angle to the long boards, with
screws in oversized holes so the long pieces can move.

Movement along the length is almost non-existent. Your end pieces are
"breadboard ends", lots of info out there on those. Depending on the
finish, 1/4" per 12" may or may not be enough.

Dewaxed shellac or oil based polyurethane do the best job at slowing
water vapor from moving in or out of the wood, but nothing will stop it.

--
When fascism comes to America, it will be wrapped in the flag and
carrying a cross.

"Dick Snyder" wrote in
:


"Leon" lcb11211@swbelldotnet wrote in message
...
On 10/25/2012 3:10 PM, Dick Snyder wrote:
I am making a cover from teak to cover the mantle on my fireplace. The
current mantle is really ugly piece of blue stone. The teak will match a
teak entertainment center I built a year ago. The mantle will be covered
on
all sides. The mantle is 74 1/2". This is in a vacation home in New
Hampshire. It will be down to about 55 degrees in the winter and maybe 80
degrees and humid in the summer.

OK, that was the long slow windup. Here comes the pitch. How much room
would
you leave for expansion? The side pieces will match up to some trim where
the chimney and the wall meet so I can't just make it as wide as I want.

Your advice would be greatly appreciated.

Dick Snyder




Relative no length expansion and or thickness expansion. The only
expansion that you will notice will be in solid board widths. Leave
yourself a bit of wiggle for the boards to expand and contract in width.
On a 12" wide board I would suggest as much as 1/4" wiggle room. This may
not be an issue if the width/edges of the board are not between two fixes
surfaces. If one edge is not confined there should be no issue.

Thanks. The widest board will be 7" x 74 1/2". I was most worred about
length but I do have room on width as long at I place the two end pieces,
which will be at a 90 degree angle to the long boards, with screws in
oversized holes so the long pieces can move.

On a 7-inch-wide board, you might see as much as 1/8" difference in width; thickness
changes at about half the rate that width changes, so if the board is 3/4" thick, you'll need
precision tools to measure the change in thickness. And the change in length is effectively
zero.

On 10/25/2012 5:30 PM, Dick Snyder wrote:
Thanks. The widest board will be 7" x 74 1/2". I was most worred about
length but I do have room on width as long at I place the two end pieces,
which will be at a 90 degree angle to the long boards, with screws in
oversized holes so the long pieces can move.

Every woodworker needs to keep a copy of the following in the shop:

http://www.fs.fed.us/ccrc/topics/urb...0of%20wood.pdf

As you will read, not only is the species of importance when selecting
woods based on their reaction to moisture/seasonal changes, but also the
cut off the log (quarter sawn, flat sawn, etc).

As a general rule, and for most species, if you want to reduce expansion
and contraction across your board's face, try to select quarter or rift
sawn stock for those areas/components which may be subject to
dimensional instability due to moisture/seasonal changes.

(NOTE: these tables come in extra handy when you are faced with
veneering/laminating different species of wood)

--
www.eWoodShop.com
Last update: 4/15/2010
KarlCaillouet@ (the obvious)
http://gplus.to/eWoodShop

"Larry Blanchard" wrote in message
...
On Thu, 25 Oct 2012 18:30:48 -0400, Dick Snyder wrote:

Thanks. The widest board will be 7" x 74 1/2". I was most worred about
length but I do have room on width as long at I place the two end
pieces, which will be at a 90 degree angle to the long boards, with
screws in oversized holes so the long pieces can move.

Movement along the length is almost non-existent. Your end pieces are
"breadboard ends", lots of info out there on those. Depending on the
finish, 1/4" per 12" may or may not be enough.

Dewaxed shellac or oil based polyurethane do the best job at slowing
water vapor from moving in or out of the wood, but nothing will stop it.

Thanks Larry. I will just be using teak oil on this project so it matches
the entertainment center I made.

I think the breadboard ends idea will work well. Of course this isn't
exactly a breadboard with an end piece attached to the main breadboard. My
breadboard will be two pieces of teak sandwiched over a piece of bluestone.
The breadboard end will be just over 3" high and will have to be attached to
the top and bottom boards of the sandwich with a tongue and groove. It will
will allow me to hide the mechanical fasteners on the top and bottom of the
boards that will hide the existing mantle. I can cut plugs so even the screw
heads won't be seen easily. I suppose I could even make teak dowels but I
think screw heads hidden by plugs should work well on this project.

On Thu, 25 Oct 2012 18:35:08 -0500, Swingman wrote:

Every woodworker needs to keep a copy of the following in the shop:

http://www.fs.fed.us/ccrc/topics/urb...docs/physical%
20properties%20and%20moisture%20relations%20of%20w ood.pdf

Thank you - excellent reference.

--
When fascism comes to America, it will be wrapped in the flag and
carrying a cross.

On Thu, 25 Oct 2012 18:35:08 -0500, Swingman wrote:

On 10/25/2012 5:30 PM, Dick Snyder wrote:
Thanks. The widest board will be 7" x 74 1/2". I was most worred about
length but I do have room on width as long at I place the two end pieces,
which will be at a 90 degree angle to the long boards, with screws in
oversized holes so the long pieces can move.

Every woodworker needs to keep a copy of the following in the shop:

http://www.fs.fed.us/ccrc/topics/urb...0of%20wood.pdf

As you will read, not only is the species of importance when selecting
woods based on their reaction to moisture/seasonal changes, but also the
cut off the log (quarter sawn, flat sawn, etc).

As a general rule, and for most species, if you want to reduce expansion
and contraction across your board's face, try to select quarter or rift
sawn stock for those areas/components which may be subject to
dimensional instability due to moisture/seasonal changes.

(NOTE: these tables come in extra handy when you are faced with
veneering/laminating different species of wood)

Woodworkers may find this tool handy as well:
http://woodshopwidget.com/

There are iOS and Android versions for $4 as well as a free web
version.

On Thursday, October 25, 2012 7:32:45 PM UTC-4, Doug Miller wrote:

On a 7-inch-wide board, you might see as much as 1/8" difference in width;
thickness changes at about half the rate that width changes...snip

Does that hold true for flat, quartered and rift sawn boards - or just flat/plainsawn? I haven't heard that before.

JP

JayPique wrote in
:

On Thursday, October 25, 2012 7:32:45 PM UTC-4, Doug Miller
wrote:

On a 7-inch-wide board, you might see as much as 1/8"
difference in width; thickness changes at about half the rate
that width changes...snip

Does that hold true for flat, quartered and rift sawn boards -
or just flat/plainsawn? I haven't heard that before.

It depends on the species, of course -- 1/8" over 7" is an average estimate for plainsawn
lumber. Quartersawn should be about half that much, and riftsawn in between.