Sanding Question

Arctic · Post by **Arctic** » Tue Nov 15, 2005 10:59 am

A question about sanding the Hull.
I am into the fairing process and began by using my spokeshave to begin fairing the hull. I finished that part last night and began sanding this morning. I am using a medium grit (100) sandpaper with a Random Orbital Sander. I was surprised at how fast I got the first half of the hull done- about 1/2 hour going section by section. The hull is relatively smooth to the touch- and there is a very noticible difference between the sanded and unsanded parts.
My question:
Is this enough? I was surprised at how fast I got done- I expected a least a few hours work here- Now I do not want to risk going over it some more and un-neccasarily take of more wood. The curves of the hull all seem visually smooth and I don't see or feel any noticible bumps or uneven areas. How do I know when I am done with the orbital sander??

Mark
Cantley, Quebec.

Rod Tait · Post by **Rod Tait** » Tue Nov 15, 2005 11:39 am

I would not take the chance and assume just because it looks good dry that it will look good when wetted out with epoxy. To find out if the hull is smooth, run your hands all over the hull, especially from keel to sheer and feel for uneven areas. Any uneven areas may be needed to be sanded with a fairing board. Once you are satisfied with the shape of the boat, wet it down with water and look for scratches from sanding. These will only show up when the hull is wet. Let it dry and then sand again to smooth out raised grain. You may wish to wet down again. Once you are confident that the hull has no marks, it is time to apply your glass/epoxy.

Glen Smith · Post by **Glen Smith** » Tue Nov 15, 2005 12:02 pm

If there are scratches showing during the grain raising phase, I would use 120 grit paper for the final sanding.

Arctic · Post by **Arctic** » Thu Nov 17, 2005 10:09 am

OK, I have finished going over the Hull with the 100 grit paper. I am planning on raising the grain and going over it again with the 150 grit for a final sanding. But I have a few gaps to fill and clean up first.
As far as I can tell (from feel and sight) the hull is smooth and shaped nicely. I guess raising the grain will show me the rest, and I will take care if it with the fine paper.

Thanks to Rod and Glen for the advice.

Mark
Cantley, Quebec

Juneaudave · Post by **Juneaudave** » Fri Nov 18, 2005 9:55 pm

Sounds like you did a good job!!! Couple of thoughts...I'm a big fan of the fairing board because it takes out stuff I can't really see or feel. Maybe it's the light (I now use halogen work lights) or maybe can't feel the bumps and dips because my sense of touch is lousy. I've watched auto body guys work on panels, tell me to feel the dip and I just don't get it!!!....Anyway, 1/2 hour for side of the hull seems pretty quick to me. If there is any doubt, try this...after you wet down and let it dry, take a pencle (not a pen) and put some light random marks on the hull. Then finish with the ROS with 120 (150 is not necessary) and make sure the marks are sanded out as you finish the hull. If you have to work an area excessively, it might be that you need to spend some extra time wth a fairing board to get that elusive finish we all strive for....Best Wishes...Juneaudave

Ed Houston · Post by **Ed Houston** » Mon Nov 21, 2005 10:10 am

Another trick is to use a very bright light at one end of the hull at a low angle and look for shadows.

Ed