: So far i have'nt been able to match with a hand block 80 grit what i can do
: with a DA sander 80 grit...i am sure it is simply more effort needed but
: it's not worth it.

: I'm still trying to determine if i should really use a different grit when
: using a DA sander...220 sure feels like 400 by fingertip.

Hi Patrick,
There is no actual difference between hand sanding and ROS sanding using the same grit. The difference is that a ROS does it faster. If you could hand sand at the same speed and motion as a ROS, you would get the same surface feel.
The 'scratch' depth is the same for hand or ROS, the ROS just has more scratches at different directions. That gives a satin type finish which will feel smoother but it will take more filling afterwards.
To get a good finish, you do have to go through the various grades. To get a really good finish, you start with a slightly finer grit than usual and use a lighter touch.
For kayaks, 600 is a reasonable final grade. If you want a Rolls Royce finish, go up to 2000 grit, then buff. By hand. A lot of work, but, oh, the finish.

Mike Savage
South West Cork