Saturday, April 23, 2011

Here's a bit on fairing

I faired the floats using the "candy bag method" ie put strips of fairing compound every 10cm or so, fair down to get the level, and then fill between the ridges.  I had to fill three times because the compound shrinks as it cures.  I used SP system S-Fair 600 which is a smooth, quite heavy and very expensive compound.  It's not very easily sanded and takes forever to cure.  Theory is that you'd rather spend time applying fairing compound than removing it.  In retrospect, this does not seem like the best way.  It might have been something about my fairing skills at the time, but the fact is I probably had to re apply fairing compound at low spots 20+ times before I got the desired surface finish.

From a link on Andrew's blog, I got acquainted with the air plane home builders' method of choice, and this is more or less what I have been doing now, also supported by the preferences of the pro that I had a few days, and who is back now to finish the hull.  Some problems though, as when I ask my worker (the not so pro one) to fill the low spots before he goes home, I return the next morning to find he has applied an insufficient layer of fairing compound to 3/4 of one hull side instead of filling the low spots (that I already pointed out to him) on both sides.  So had to fair almost all of it back instead of the patches before the big fill.  That's life when time has to be divided to several tasks and obligations.
I also changed to mixing up my own compound.  This seemed to me as an unpleasant task at first, but it's not that bad actually.  I use Svapox epoxy with GL hardener, an inexpensive laminating system with a medium working time, and add 27% weight (about 300% volume I'd guess) of micro glass balloons to get a non sagging, quite dry (have to use force and slow speed for it to attach properly) and light, easily sanded compound.  The point is to fill ENOUGH to fill all low spots, then sand back to the correct contouring in one go.  Preferably, the low spots should be pre filled and sanded when not fully cured (cheese grating) in order to avoid any low spots to occur due to crimp during cure.  I use my favourite grit 40 on the rigid board until I have the perfect shape and see the high spots of the laminate shining trough the filler.  This saves huge on time spent, and it is much easier to get an even surface compared to the patchwork on the floats.  Then it's time top fill pin holes, and change to finer grit to prepare for the water penetration barrier.
I guess all this is subjective, but this is my experience.

A few shots of the situation after removing 90% of yesterday's compound today:

These kind of disrupted surfaces takes a lot of time:

And I finally made the hole in the bobstay anchor, had been postponing it for a few years:

Friday, April 22, 2011

Turned around, I'm constantly covered in dust

Couldn't resist taking a photo of myself in front of the wing.

The heater have burned increasingly erratic lately, so it was time to check what was going on.  I took out the burner head, and that was not pretty:

After cleaning, and it burns better but not perfect.  I should have controlled the integrated pump filter and checked that it delivers 11 bar, but I didn't figure out how to get the pump out.  It works for now.

Yesterday, the top side finally started to look quite good, and the hibuild primer and engine control that I ordered mid march had not yet arrived, so further progress required a flipped hull.  I have had occasional help, but not by a craftsman, so I have to redo most of the finishing work.  It still helps speeding up this work, that I must admit, is not the part I enjoy the most in boat building.

The main hull now entirely covered in fairing compound.  I hope I won't see the boat in this position too often....

The faired tiller and mast raising pole still in progress

I will have a Teleflex engine control (still on backorder) under the cockpit seat, and a Spinlock ATCU unit for engine control with winch handle on the seat front.  I need the Teleflex unit before the exact position can be determined, and then I have to insert a tube trough the aft cabin for the control cables and the fuel line. Hopefully, this will be done by next week.

Then pads for mast foot, winches and pulpit attachment points will be made before the Hempel high build (still on backorder) can be sprayed.  Then, off to the paint shop.

Temperatures are more and more often in excess of 10ºC so just ten more to go and I can finish the mast.

That's it for now, going back to the dust

Tuesday, April 05, 2011

Mast raising pole. Tiller. Fairing.

This might seem crazy, but in fact it is much easier for me to mock up a piece of carbon tube from cut-offs I have in the workshop than to source a piece of aluminium tube.  So I'll have a carbon mast raising pole.  The socket is in the barn, divided from the mast by a sheet of plastic, where it will hopefully cure enough to bring back to the workshop for final curing and attachment to the pole. A propose weather, someone might recall me whining about wind blowing out my heater, it was actually recorded 68 knots of wind on the farm that day.  That's pretty windy.

Mast raising pole made up over a 2" PVC tube sprayed with silicon grease, wrapped with a piece of plastic and packaging tape used over the peel ply to compact the lay up.  Worked great, this pole is probably better than my bow pole.  Tiller seen behind.  Very light and stiff.

After adding a 1/2" ID G10 tube to the bow web, I cut off the excess on each side and glued them in the "ears" of the bow pole to act as bushings protecting the carbon.  Kept in line with the SS pin while curing.

The mast raising pole and the bow pole curing in front of the heater.

The tiller dry fitted to the daggerboard rudder case.  I also made a pedestalish extension on the tiller to accept the pin for the tiller pilot.

And further fairing.  Unfortunately, I hired two professionals to fair the boat, but one of them didn't show up, and the other one is too busy to work much on the boat.  He does a good job when he is there though. That's the end of the June 6th plan I guess....

Monday, April 04, 2011

Slightly off topic

As my hired help did a good job with the fairing last week, this is what was my struggle.

Provisions for tillerpilot. Windows. Tiller. More fairing.

I updated my last post with a couple of pictures.  My camera has been on unknown location for about a month now, I start to suspect it will not show up.  Pictures from my phone.

I ended with the Raymarine ST 2000+  autopilot.  It will be connected by NMEA 0183 to my Nexus NX2 system.  I finally found someone who could give me answers to my enquiries regarding wireless and carbon, and he had rebuilt several TackTick systems to the wired Nexus after adding a carbon square head main sail to glass boats, and he was quite certain that wireless would not work in my boat.

I added a pedestal for the tillerpilot.

I have also added HD inserts for clutches on deck.  And the mast raising wire brackets were finally finished so the position for the attachment plate could be established.  Drilled and backfilled for those in the cabin side. Made the cut outs for the windows.

Also, I finally got the 1/2" rudder pivot pin and was able to start making the tiller.  I made it up from two 4cm wide strips of 15mm Divinycell H100 with a layer of UD carbon in between, to make it stiff enough for further handling.  When heat shaping the strips one by one it is easy to get any shape.  Then glueing them together and keep them in the right shape while curing.

It seems it will even clear the engine, at least almost!  PS fairing the cockpit, swim step, beam recesses etc is a lot of work!