I would like to use the forum to share practical building experience.
We (my wife and I) built 13 boats so far. Lets talk about sanding.
One of the works which have to be repeated often when working in the
wood/glass Epoxy system and even more so when working with foam
sandwich system.
The most important tool is a very good sander. Epoxy gets thermoplast
again above about 75 degree Celsius. Which means, when you use an
ordinary oscillating sander which vibrates 20000 times or more a
minute and the wrong sanding paper, the only effect you get is clocked
sand paper.
So which sander is the best for this ?
We use a linear sander which has a 5mm rotating movement and a
rotation speed between 2000 to 6000 revolution. As sanding paper we
use Aluminum oxide paper (grain 85 and to finish 120).
This sanding paper will not clock as easily as normal sanding paper.
It last about 8 times as long also. By the slow rotation of the sander
the Epoxy will not get thermoplast . This machines work whit almost no
manual pressure. The are not cheap but worth every penny.
The relative new orbital sanders are not bad also. But you have to
hold them absolute parallel to the working surface. Otherwise you get
immediately marks which have to be filled again.
Preparing a perfect putty will help also to easy the work. This will
be a story for an other time.
Cheers
Bernd
Bernd Kohler