Here are my conclusions regarding that long thread I started about using
Ping Pong Balls for floatation..

Ping Pong balls are not cost effective. $20/144
PPB burn real nice.
PPB are relatively fragile.

2 Liter Soda Bottles are cost effective.
2 LSB can withstand the temp changes here in New England.
2 LSB looses volume quickly under external pressure. Designed mainly for
internal pressure.

Both will degrade in direct sunlight.

What will I do? More than likely I will fall in with everybody else and
use 2 part. I'll just have to make allowances for moisture to be able to
flow from bow to stern. With either of the other methods I would not
have to do this.

Thanks to all that posted.

--
Tailgunner
http://boat.nbrigham.com