Robert Bonomi wrote:
In article 2005051513181916807%ericblair@pillarboxcom,
Eric wrote:

I have to make an interior window ledge that is 13.5 feet long. I am
using Peruvian Walnut, and the longest boards I can find are 9ft. So..
I need to glue the pieces together. I intend to do this by adding two
pieces to either end of the main piece. I have never glued end grain to
end grain before and wondered if there is anything I should be wary of.
I could use Titebond or Gorilla glue, is there any advantage to one
over the other?

Other than my biggest issue might be finding bar clamp long enough. I
have the Rockler clamps and I am not sure they can be extended or used
with longer bars.

Thanks in advance for any comments/advice.


(A) simply butting end-grain to end-grain is *not* a good idea. at a
minimum, consider using a lap joint, like this:

---------------------+-----------
|
+---------+
|
-----------+---------------------


(B) Any good wood glue will be fine. I don't see any 'need' for the
price premium for Gorilla Glue.

There _might_ be a need for a "stretchy" glue -- say the type you use
for lamination if there is a lot of expansion and contraction cycles in
that window. (Hot sunny days, cool nights etc.) And Gorilla Glue is that
stretchy type for laminations. Other than that... And of course some
glues are more heat resistant than others.

I know Lee Valley has some good explanations of glues on their sites.

Also See Fine Woodworking April,2005 #176 page 42.

A minor issue in an otherwise great explanation. IMO


(C) there are lots of ways to clamp up things like this that do _not_
require ridiculously long bar clamps. However, if you do insist
on applying end-to-end pressure, the solution is 'pipe clamps',
e.g. "Pony". use a long enough piece of pipe, and they will
clamp "anything". Recommended is multiple lengths of 4' pipe,
threaded on _both_ ends. Then you simply use inside-threaded
'sleeves' to join multiple sections to the length required.
(the advantage to this is you can disassemble it after use,
eliminating the need to store that say, 14' piece of pipe.

To clamp such a glue-up without requiring long clamps, first clamp
a couple of pieces of scrap stock (one on each side of the piece)
a moderate distance back from the joint edge. thusly:

__ __
/ | | \
+-+ | | +-+
+-+ | | +-+
---------------------+-----------
| | |
| +---------+ |
| | |
-----------+---------------------
+-+ | | +-+
+-+ | | +-+
\_| |_/
| |
| |
| |

then, put clamps across those 'scrap' blocks, thusly:


+-------------------------------+-------
\+-+ +-+/
+-+ +-+
---------------------+-----------
|
+---------+
|
-----------+---------------------
+-+ +-+
/+-+ +-+\
+-------------------------------+-------

It is important to get equal tensioning on both sides of the board.
otherwise you will introduce warping.

Note: you can cross-clamp _on_ the joint as well, to help hold it flat,
or by using a reverse taper on the edges, you can make the joint
'self locking', as follows:

+-------------------------------+-------
\+-+ +-+/
+-+ +-+
-------------------+-------------
\
+---------+
\
-------------+-------------------
+-+ +-+
/+-+ +-+\
+-------------------------------+-------



--
Will
Occasional Techno-geek