Team Seacats

Last night I ended up helping a friend in desperation who’s air conditioner compressor quit working that afternoon.  We put a new one in and got his a/c up and running for the hot day we had today!  David brought beer so I didn’t get much else done.

Tonight, however, I started by cleaning up the one face of the rudder mold, brushing away the clay in the seams and washing away the PVA.  I hot-glued my plastic fence at the trailing edge of the rudder (more on that once I separate the mold).  Pictures are still from the camera phone – so the quality leaves a little to be desired.  The replacement charger should be here next week for our camera.

Once that was done, I waxed the new face three times with the mold release wax (designed to be used with the same brand of PVA) and shot three or four coats of PVA on the plug.  Once the last coat of PVA dried (30 minutes or so), I mixed up some gelocat and brushed it on using a disposable chip brush this time instead of one of the foamies…it worked a little better.  Again, still not as nice as spraying it, but there’s MUCH less cleanup.

Once the gelcoat was given about 30 to 45 minutes to firm up and be tacky, next came the thickened resin with milled fiberglass and some microballoons for good consistency.  The milled glass fibers make a very dense (and heavy) filler but they can make it too dry by the time you get the thickness right.  Getting it about halfway there with the glass fibers and finish with microballoons makes a very workable mixture.  Colloidal Silica would be the preferable filler but I don’t have any at the moment.  I put the filler in the alignment holes and on the sharp edge of the fence so the fiberglass won’t have to make any sharp bends and not bond well.

After that, I put two layers of 3.5oz satin weave cloth on (to reduce print-through into the mold surface) followed by about 7 or 8 layers of 5 oz cloth – some layers at 45 degrees to the next.  It’s curing now and should be ready to perhaps attempt a separation in the morning (if I get up early enough before work). If everything went well, I should be able to mold up a real rudder over the next couple of evenings.

Our buddy building the SR-71 Blackbird has another brief update. He’s laid out a fuselage half with two layers of glass and some carbon in areas….and I thought my project was cumbersome!

OK, weekend wrap-up; First, sorry again for the photo quality…we still haven’t found the camera charger and I’m using Bonnie’s phone.  I’ve given up on finding it and ordered a new charger. 

I accomplished quite a bit this weekend with the one meter.  I really wanted to get the rudder knocked out so I drew up a tapered NACA 63-010 foil shape rudder and designed it and the pivot to fit the rear of the computer model of the boat.  I printed out several drawings of the foil with several key dimensions and got started shaping a piece of solid mahogany (that I salvaged from the trash at a gas station in Hilton Head nearly 6 years ago).  I intentionally made the rudder a little longer than I really thought necessary since I can make it shorter much easier than I can make one longer.

After cutting a profile shape and cutting it to the maximum width in the table saw and making the taper, I marked several center lines and measurements on the stock.  I then flipped and mounted a hand held belt sander upside down on my work bench and worked the rudder plug carefully by shaping and taking measurements as I went.  Once shaped, I needed to drill the hole for the post so I carefully mounted the rudder stock, using tape, to a square and adjusted the mounting with wedges to get it plumb and square.  This would have been much easier if I had done this before I started shaping the rudder!  I had less than 1/16″ of material to spare on each side of the post, but somehow the post hole drilled centered, straight, and true.

For some reason, I had a very difficult time getting paint to cure properly on the plug and only after stripping the plug twice and going out to purchase new paint did I begin to have some (limited) success…never did figure out what was going on there (I even had the A/C on in the shop to keep the humidity below 60% – it was raining at the time).  Once I finally got a good coat of primer on and sanded smooth, I started with the black paint, some sanding, and a clear coat.  After more wetsanding from 400 to 1500 grit paper, I polished the plug with a polishing compound and my mushroom buffing pad in my die grinder.  I then mounted the rudder pivot tube into the rear of the boat and I must say everything fits and lines up nicely.

How’s thats for a shiny finish on the rudder? (it’s sitting in the fence just before molding)

I then jigged up a parting fence to make two half-molds of this rudder and the post using some scrap lexan and the clay again for the joint.  After waxing everything (yeah! I remembered!) three times, I shot the PVA on the plug and fence, let that dry between coats, and brushed on two coats of orange tooling gel coat.  Slurry on the sharp corners…yada yada….first half of the mold is laminated and curing tonight.

shown here before filler and glass.  I’m still not tickled with how gelcoat brushes on.

In between waiting for paint to dry, I worked on the backstay plate.  This is a bit unusal because of a rigging idea I intend to carry out on this boat.  I’m going to run a drum winch inside the hull and have to sheet and return line running into the vertical rear wall of the boat in two very small brass grommets.  The lines will turn around two sheaves mounted on the rear backstay plate so they can run horizontally on top of the deck where the jib sheet and mainsheet will attach to them.  I’ve never seen one done this way…but you can’t come up with good ideas without pushing the limits sometimes ….anyway, I used yet another piece of that carbon fiber plate that I made several months ago after carefully proving out the geometry with the mast and backstay attached.  I dremeled out the slot in the rear deck for the upright and slid the plate in place and glued it with thickened epoxy (reaching inside the hull and coating it thickly).  If I do this again, the plate will be mounted before the rear deck goes in so I will have an opportunity to glass this plate in…I don’t have the highest of confidence that this piece won’t break loose…I think it will be OK but I would feel better if it had some glass on it.  However, with the deck already in place, there was just no way to get enough access without a major operation.

 

We still haven’t found that darn camera charger.  Anyone got an old one laying around for a Sony DSC-S50?  Fortunately, Bonnie’s phone has a camera although it seems to struggle a little with close focus shots.  Here’s something anyway.

I managed to shape out a rudder to a Naca 63-010 foil shape and it looks incredible!  Unfortunately, the batteries for our camera are dead and neither Bonnie or I can find the stinking charger.  I’m sure I left it somewhere strange.

I started with a nice dry piece of dimensionally stable mahogany and cut out the profile with my band saw.  I then sanded all the edges nice and flat and ran the pieces through the table saw to end up with a thickness just over 3/16″.  After firmly marking the deepest width of the foil (based on the computer model) and marking the center of the leading and trailing edges, I then mounted a hand-held belt sander (with a nice long flat bed) upside-down to my workbench and started gently working the piece to shape.  I must say, the result was exceptional and very very close to the design model.  I’ve put some primer on it and will sort out a way to insert the rudder shaft straight and square as per the design parameters over the weekend.  Once that’s done, I’ll paint, sand, clearcoat, and build a mold from this plug.  It’s a very high aspect ratio rudder that should easily be able to dig in at the most extreme angles of heal that is very straight, true, and fair….damn, I wish that camera were operational!