I second that - I use a foam sanding block but ONLY for the last phases of wetsanding.
For shaping, fairing, and filling, I use a home-made long board that has served me very well.
![[Linked Image]](http://static.flickr.com/30/100256101_bf93a363e1.jpg)
The hull on the right had not yet been polished.
![[Linked Image]](http://static.flickr.com/45/130500406_cb8e23017b.jpg)
I made a smaller version of the long board for this project: