July, 1
A new blog format and a new phase of the boat construction. Yesterday, I created the first 16 ft strips for the hull laminations. I used a machine that I made to scarf join 8 ft strips together. With a little adjustment it worked very well.
A close up of the blade (turned off). See the nice even pattern in the layers of the plywood. This means that I have achieved a nice even scarf joint. |
1/4" X 12" X 16' strips of planking. The scarf joints are held tight with bar clamps while the epoxy cures. |
I've ripped a total of 6 sheets of plywood and cut a scarf on all but the last piece. This is enough plywood to make 12 16 ft pieces (~200 sqr ft). On the last piece, a bolt holding the blade guard came out. While clearing the waste piece, the waste piece jammed the guard into the blade. This would have been prevented by the bolt which was no longer there. The guard jammed the blade to a halt slamming the grinder and guard back into my finger. The finger survived but is cut and bruised. The cut isn't that deep but the bruising makes it pretty sore. Ironically, the guard caused the problem and protected me at the same time. I will have to rebuild the guard. I'll make the new guard out to 16 gauge steel to avoid the blade from grabbing it in the even of a blade strike. I also plan to use Loctite threadlocker on the bolts so that they do not vibrate free. Lesson learned and no loss of fingers. I'll get some pictures of the old and new guard soon.
Jan 12, 2014 update - actually that finger injury took almost 4 months to heal and I still have residual stiffness in the first joint. The cut was deep and blunt so I think a lot of damage was done. I was both lucky and unlucky at the same time. Be careful out there.
Nothing says independence to me like working on the boat. I've fully repaired and tested the scarf cutting machine.
A side view. |
I've also worked on the bonding strips for the boat. I'll add so considerable text about bonding soon. For now, the bonding strips are 1" X 1/8" copper strips that run almost the length of the boat on either side of the keel. Purchasing bar stock would have been very expensive. I have a friend in the sheet metal business that had some 1/8" sheets and he cut some strip from them at a very nice price (actually less than the per pound price at this time since he'd had the copper laying around for some time). The only issue is that shearing the copper caused the strips to twist so I had to take the twist out.
So what is bonding anyway? From Miller/Maloney's book Your Boat's Electrical System, they say there are four reasons to bond your boat:
- Bonding provides a low resistance electrical path between otherwise isolated metallic objects, reducing the possibility of electrolytic corrosion due to stray currents between objects.
- Bonding prevents the possibility of above-ground electrical potential on exposed metallic cases and parts of electrical equipment should fail should a fault develop in such a device.
- Bonding provides a low-resistance path to ground for voltages higher than system potential, as, for example, during a lightning strike.
- Bonding minimizes radio interference.
July, 7
I've glued some more of the plywood together and cut some more scarf joints. The new and improved machine actually works better than the last incarnation. The guard is much more stable and hopefully safer. I also put in a few more hours of sanding the keel so there is a smooth transition to the hull.
July, sometime
I've managed to straightened these copper strips out and I'll tell you it was not easy. I'm not sure it was worth the effort but I did save quite a bit of money.
Bonding strips straightened out with flanges bent on the ends. These are ready to install. |
The first three strips installed and sanded. I've decided to sand as I go. Once all the plywood is on, access will be more difficult. |
Two more strips installed. |