Sunday, May 29, 2011

The skim coat process

After the contouring, there will be millions, ok hundreds, of pinholes in the surface.  I have used a method very similar to the method described in Wayne Hick's chapter 25 to fill these and large scratches. I use a fast epoxy with about 5% by weight microballoons added, apply with a squeegee, wait for a while and then remove as much as possible.  This fills quite well and also hardens the micro substantially, as well as it serves as a water barrier.  I sand with 120 grit, which is quite easy as the layer is very thin and only the small bumps from the ends of the squeegee has to be removed.  This has proven to be a much better way, although quite labour intensive, than the roll and tip epoxy coat I applied to the floats.  Several skim coats are recommended, but I have decided rather to sail this summer than to achieve a piano finish.

 Skim coat on aft cabin area

Making pad for the starboard cabin top winch

 For the mast foot

I used Jotun's high build primer for the floats.  This was filled with aluminum and also impossible to sand.  So I was recommended the Hempel stuff, but this proved impossible to source.  So I use a regular epoxy primer (made primarily for use as a water barrier on polyester hulls) and add approximately 20% by volume/2% by weight of microballoons.

Cockpit still with the skim coat only. 

I'm sanding the high build down with 180 grit and finally see how well I succeeded in contouring the patchwork.  At least I found some irregularities on the port bow...

I'm getting closer anyway.  And a wise guy stated somewhere, probably on the f-boat forum, that you never finish fairing a boat, you just decide to stop at some point.  I'm not far from that point now.

Sunday, May 22, 2011

Preparations to the top side

I was done with the contouring above gunwhale.  However, someone has been using a random orbital sander and some areas are not longer the correct contour, although with a very fine finish.  Arrrgh! I don't know yet how much attention I will pay to this. Also, the beam recesses was finished, and I also told so to my workers that no more work was needed there, but they still managed to put a lot of filler into the upper folding strut recesses, which was a pain to get out.  Silas did a great job helping me with that.

A few small projects was not finished, like the engine control.  I had to put the engine back on, rebuild it to accommodate remote control, and decide on the placement of the tube for control wires and gas.

In the cockpit, I had to glue back in a piece of a cut out to accommodate the Teleflex mechanism with the flush Spinlock front plate for winch handle. (I was hoping to fit this in the extended part of the coaming but this turned out to be too tight)

Some more work on the front deck was needed after building back up the flat panels under the bow nets each side (second time I do this).  Then I marked the position of HD and drilled for pulpit and fairleads.  I will have to build up a pad for the aft pulpit support.

And I have to make pads for winches and mastfoot.

I have faired the modified part of the cockpit

And I made a 2" tube for the control wires, fuel hose and electrical wires from the engine.  Still to be glued,  laminated and trimmed to fit. This tube runs from the aft cabin transom

Trough the aft cabin, where it serves as a perfect hand rail (and possibly a shelf front)

And enters the under settee compartment

Thursday, May 19, 2011

Some thoughts on using hired help for an F-boat

Sorry all, long time no updates. I've been too upset and busy to sit down and write. I had originally dismissed the thought of using help for the fairing, mainly because I did not expect to find anyone able to do the work to my standards within a tolerable cost. Then I got these two guys recommended by the painter and I could see the boat finished maybe two months earlier. The problems rose before work started, as they did not show up. Then one showed up for two days instead of two until finished, and so on. It did look, however, as he was doing a good job. I was not able to be there and help and guide, mostly during Easter, but I had given instructions, or so I thought. By the end of Easter my costs had reached $5.000, the boat was more bumpy than ever and worst: It was covered in patches of fairing compound of different mix ratios. And on top of that, fine fairing using electrical tools had started. Even those areas already finished by me before this week had been ruined. That is when I ended their engagement.

Since then I have spent every available minute sweating over the longboard, trying to save the boat. It looked like I had to do another big fill, but it seems now I will be able to get an acceptable finish, although not as I hoped, by thorough work with the longboard and a few extra highbuild fills. No need to say, the boat was not ready for painting early April as planned, as it is still not so. I'm getting closer, though.

This is after about one and a half week of sanding with 40 grit.  Most of the big bumps are removed.

Couple of days later.  A test run of modified highbuild is applied.  Never succeeded in sourcing the Hempel High Protect that was supposed to be good.  The Jotun HB I used for the floats are banned; contains aluminium and is almost impossible to sand. I make my own now from Biltema Epoxy Primer added a modest amount of Microballoons.

Around 90% of the filler is now see trough to the laminate, which means the hull itself was very fair.  The last unevenness are extremely hard to remove as the differences in hardness of the various batches of fairing compound come into play.

The scimming coat done to the lower half of the hull.This is a mix of about 5% microballoons in epoxy, and it fills the pinholes well as well as it fills up the surface of the micro and harden it. I have tried different methods of applying, using roller and squeegee.  Then I remove all I can with a steel squeegee.  I think the best is to apply with a plastic squeegee, and be cautious to remove the epoxy when it starts getting dry. This happens quite fast depending on the state of the micro, as epoxy is "sucked" into the surface of the filler.

 The waterline was established using a laser leveller and then taped

Jotun Antipest sealing eposy applied to the underwater area.