A New Phase - July 2013

The posts from now on will be monthly.  I've pretty much filled in all the back work till the present.  I realize that some of you who read this blog might not realize content was added even though no new page was generated.  I did this because I wanted a comprehensive story of the work done to date.  For  now on, the monthly blog page will be filled out as the month progresses until the end of the month in which time I'll start a new page.

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.

Here is an overview of the machine.  The wooden bar across the table holds down the plywood while the blade is pushed into the wood.  The rails hold the motor and blade true.  I recently added the switch so I would not have to reach under the blade to turn the motor off.  I felt this was a good safety measure.  The motor is a DeWalt electric 5" angle grinder bolted onto a steel frame.  Don't try this at home.

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 temporarily placed this first strip on the hull this morning to see how it would go.  The process is going to take a bit of a learning curve not to mention quite a few clamps.  When I was done, I was very pleased with how it laid on the hull.  

July 2,

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.

This was the old guard.  It was made our of 16 ga galvanized and spot welded.  It had supports on either side and at the top.  One of the supports vibrated loose and a waste piece pushed the guard into the blade.  You can see on the right where the blade cut through the guard and then at the top where it snagged in the guard kicking it back.

July 4, 2013

Nothing says independence to me like working on the boat.  I've fully repaired and tested the scarf cutting machine.

The new guard made from 20 ga steel continuously welded.   I'm going to add Loctite to the bolts so that they will not vibrate loose.  This guard should take a blade strike without instantly cutting through.  Also, since it is continuously welded it should no snag.

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.

a few of the copper bonding strips.  Notice the twist in them.  This occurs during the shearing process.  The shear is like a guillotine and cuts the copper sheet from one side to the other and not all at once.  This tends to twist the metal.  The twist would be barely noticeable with steel but copper is relatively soft.  

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:

1. Bonding provides a low resistance electrical path between otherwise isolated metallic objects, reducing the possibility of electrolytic corrosion due to stray currents between objects.
2. 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.
3. Bonding provides a low-resistance path to ground for voltages higher than system potential, as, for example, during a lightning strike.
4. Bonding minimizes radio interference.

All powered items should have their cases connected to the bonding system including the engine, auxiliary power plant, electrical cabinets, etc.  Zinc blocks and all through hull fittings will also be connected to the bonding system.

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.

I've installed three of the strips at this point.  Notice the short horizontal boards attached along the seams.  These are temporary blocks attached between the longitudinal battens to hold the plywood strips flush with the hull.  Oh, and that is my wife off to the right encouraging me. 

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.