[ATM] RE: Berry's 10-inch telescope plans

["lou krajci" <loukrajci@comcast.net>]

>From: Thomas Rutherford <rutherfordt@earthlink.net>

>Originally, I had also planned to build everything from construction
>grade plywood because that is what I already had on hand, but I have now
>decided not to do so.  Instead, I have located and purchased some
>plywood at Home Depot called "Sandply."  I don't know what type of wood
>it is, but it is smoothly finished on both sides and has more plies than
>construction grade material does....

For those that are building larger, or going lighter...stiffness to weight
ratio is an important consideration.  If you're gonna use plywood, are there
any easy ways to compare different brands of plywood in this regard?

One idea I've tried is to walk through a big place like Home Depot...pick up
pieces of various grade of 3/4 plywood that are the same size (such as 4ft x
4ft)...hold them in the air by one corner and give them a rap with my fist.
The piece of plywood will 'ring' at its resonant frequency...at least for a
short time.  The brand of plywood with the best stiffness to weight ratio
will have the highest oscillation frequency...or will it?  Am I making
errors in thinking here?

Feedback is appreciated.

Tom Krajci
Albuquerque
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.752 / Virus Database: 503 - Release Date: 9/3/2004

_______________________________________________
ATM mailing list http://www.atmlist.net/