Remember that when Al recommends placing the boards the way that he
did, all it does is eliminate the tendency of the wood to cup in that
direction. It may still cup the other way.

If it was me, I'd use or 3/4" or 1" plywood. That will be more than
strong enough for your application.

Plywood will be dimensionally stable as well. With the planks, you
will eventually end up with gaps between each board pretty much no
matter what you do to try to eliminate them.

On Sat, 30 Aug 2003 00:05:10 GMT, "Al"
wrote:

Bill,

As you mention below, when the center/core of tree lies ABOVE the plank as
it rests flat on the ground, the cupping should be such that the edges curl
up. If you want to minimize cupping with time, using smaller width planks
(4" instead of 8") would be very useful or just rip the planks to smaller
widths. Using an exterior grade of plywood instead of planks would
eliminate the problem completely.

Al

"BllFs6" wrote in message
...
Hi all....

this is off topic but I figure there are enough telescope makers/
woodworkers
here ...

.so I ask
....

I am rebuilding a trailer in which the only part left is the metal
frame....

I am planning on redoing the bottom of the trailer with wood
planks....pressure
treated 1 by 8's....

So, lets say Iam looking at the end of a plank where I can see the tree
rings...and say on this particular slice I can tell that where the
center/core
of the tree was lies ABOVE the plank as it rest flat on the ground...


In that position....as the wood ages and dries out over the years....are
the
sides going to curl UP or DOWN?

Iam asking because I want the edges to curl down over time...ie I
definitely
prefer the plank to become convex rather than concave...

Or do I need to flip all the planks over so that where the center of the
tree
was lies BELOW the planks rather than above?

Thanks for any input!

Bll