Whilst waiting for the shoulder injury to subside, I had a chance to work on my tools and organise everything.. I mean everything.. I had my pencils lined up by length..

To help readers catch up, one hull was a real mess due to a bad batch of hardener after dealing with extreme outgassing of the composite After spending a month in the sun to cure the resin and in the moving process, the surface on the hull was as tough as it was rough and I wanted to remove as much of it as possible and re-coat the bogg. I was also very concerned with the fair. The kind of grinding I was doing was an invitation to a poor surface.
To attack the job I found a cheap and controllable sander/polisher. This, armed with a disc of #36 sandpaper would actually cut through the stuff but controlling the thing is shoulder work.... After that I used my modified inline air sander.. which did a fine job of taking off the high spots in preparation for a scrim coat of bogg that would seal the pits from outgassing and give a smooth and fair substrate for further work.
An important note about the outgassing.. if you are building a boat with ply, or particularly balsa core panels, and are having problems with pits in your bogg or high build surface that seem hard to fill, you better look at the TCP web site!! If you are applying bogg or any resin to the surfaces and you aren’t doing it at night or late in the day, you may be compromising the future of your boat.
But back to the sander, these cheap air tools have a massive potential but some limitations. Modified as described herein, it does the job of a torture board but with less side to side, arm and shoulder movement. To use this tool you need a powerful air compressor. Mine is 13.5 CFM which allows me to use the tool for a short period of time, say 5-10 minutes, before it runs a little low and then I swap to another type of tool, like my Rupes planetary orbital, to go over the area just worked by the inline air sander, with a finer grit, until the compressor builds more pressure. I have been using 60 grit on the air tool. Another problem it had was spitting oil all over the job which is bad news working with fibreglass. Any oil left on the surface will prevent adhesion of resin or paint. I got around that. The air sander has two pistons on either end of the body. They are covered with caps using allen head screws. I removed them and wiped out the oil that comes from the factory and swabbed on a light coat of grease. I also unscrewed that big brass plug on top and did the same. Regrease after about every 8-12 hours of use. I also provided extra hose between the air compressor tank and regulator to allow cooling and thus prevent some condensed moisture from reaching the tool.
Another shortcoming was the sanding pad. It was too small and with a rubber pad. I cut a piece of FLAT12mm ply, 600 X 100, drilled two holes for mounting the screws and stuck it on. I did have to supply two longer 1/4 inch screws. I staple the sandpaper on just like my torture board and without the rubber pad the board makes a very flat, true surface.
Since modification the sander works better, faster and I haven’t had a drop of oil on my work since I converted to grease. It really is a time and muscle saver.

I was shown a plastic sanding gadget at the local boat yard that seemed interesting but fragile. It had been repaired already. The idea is one I am familiar with as a jeweller. A “split lap” is used to polish jewellery where seeing what you are doing as you are doing it is important. So I fabricated one in more durable, high tensile aluminium, applied some 80 grit on velcro and gave it a try mounted on my new $99 sander/polisher. Works a treat!! It covers a large area fast, you can see every detail through it whilst working and the size of it helps keep a fair surface.
I think this tool will be most valuable when preparing bogg for paint and in finishing high build to prep for top coat.

  A mate tried out my first attempt and it seemed OK to him except he found it would dig in on a slight concave surface, leaving “smiley faces” on the high sides. I believe I have fixed that problem by installing a foam surface to the ‘wings’ that will ‘give’ just enough. I may even try a larger version, perhaps twice the diameter and powered by an air tool. For $40 in materials and an hour to build, I am very satisfied with it.
Sanding is the biggest, high labour part of the job and the easiest to screw up. Having equipment that will speed up the process and increase control is invaluable. I will mount more detail on the web site about the construction of Split Sander. It measures 300mm/1 foot diameter. The 1500 watt polisher is from Bunning’s and so far it has been excellent. It has an amazing speed control.

Here are instructions for making your own.

Fibre glass is notorious for dulling conventional teeth type cutters. This jig saw blade I found is loaded with carbide grit, no teeth. It cost $15 but I have been using it for months and it should last the project.

A tile cutter from the local hardware store works as good as anything. It is diamond scintered. They aren't all alike. Better quality uses more diamond grit. Careful not to overheat, let it set it's own pace. If they get red hot they may warp and forever after want to cut a curve instead of a straight line.

I had to do something or go crazy sitting around. I managed to make some progress with this board and once I got used to it I found it actually pretty good.