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The radio tray is installed. The large taper on the tray both accomodates the widening of the hull and puts the tray at a bit of an angle so that the line enters the winch in a straight line. Pictures of the installation coming tomorrow. The entire tray weighs slightly more than 0.5oz!!!
Today we finish the radio tray installation…here’s the plan…I left some extra room for the battery because until I get a special LiPo charger, I’m going to use the 600mA Nicad that came with the radio. I know that’s not much capacity for a day of sailing, but I do have three or four of these packs lying around.
I made my first, and last, rudder out of the new rudder mold. The result was pretty good. Although I brushed in an early thin layer of epoxy in the mold with the intent of holding a nice outside finish, I didn’t let it cure enough before vacuum bagging the carbon and the vacuum sucked the still-to-soft resin out leaving some pinholes between the carbon weave. After trimming away the rest of the pieces, I put in some filler but will probably have to make another pass to get it right. I filled the core with a thick epoxy / microballoons (tinted dark gray) before sandwiching the two cured skins back together in the mold. The rudder looks good and while it is probably about average in weight, I think I can cut a little more weight out of it. The brass rod itself weighs as much as the rudder so first step would be to find a lighter alternative.
Oh, the reason for the “last rudder out of this mold”? The newest mold-half warped badly while cooling after I left it in the sun curing the rudder. I’m getting tired of looking at this rudder mold and don’t think I’ll remake this half again until I need another rudder. I think maybe I laminated the mold too thickly in one step…or something. Might have to talk to some folks to figure out how to keep this from happening again.
I also worked out the bulkhead and radio tray material. I took some light weight PVC foam and ripped out a .25″ thick sheet from a large block. I then planned the position of the main servo winch and using a razor blade, cut out the foam to receive two balsa blocks to provide something to screw into for the winch servo mounting. I then vacuum bagged one layer of 5.7oz carbon cloth using epoxy resin to each side of the foam. It’s amazing stuff. The whole sheet ways a touch over 2oz and is enough to make the main bulkhead and the radio tray. I admit to being a little stumped for a while trying to figure out how to template the bulkhead without a ton of trail and error fitting. I finally decided to utilize the hull molds to make a template so I marked the position on the molds with electrical tape and laid up two layers of 1″ fiberglass tape in the same area where the bulkhead will be inserted into the hull and used those to trace a template on the foam core carbon material. After trimming the carbon, I fitted the bulkhead and with only some minor cleanup of the resin where I had placed fixtures inside the hull it fit perfectly. The bulkhead is flat on the bottom leaving an opening for water to drain out of the front of the boat should there ever be a reason to do so. It will be much easier to perform the assembly of the shroud connection points and mast compression post in one step next time.
Aaaaaa…more on that later….I’m not sure which needs a rest more – the washing machine, or my favorite t-shirt…
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.
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.
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 did manage to squeeze out another mold last night. This time it was a mold of the finished rear deck so I can more easily reproduce them in the future. I tried, for the first time, brushing on the gelcoat instead of going through the process of spraying it. It was certainly faster, but it was very difficult to get a smooth thick coat. If I brush it on again in the future, I will probably plan for two small batches and at least two coats in between opportunity for the gel coat to tack up. I also tried, for the second time, to apply PVA over a primered surface. Because this mold was mostly going to be an “outy”, I figured I wouldn’t spend too much time trying to get the finish right on the “inny” surface of the rear deck and figured that with the wax and PVA, release should be relatively easy. It will be easier to wetsand the mold surface and polish it to a really smooth sheen since it is more male shaped. This worked well except that I still had a little difficulty separating the mold in the areas that were difficult to buff the wax. I think if I had applied a smoother finish coat of paint instead of the primer, the PVA would have worked a little better. You don’t see primer in that photo because I wiped it away with acetone because it was mottled from sticking to the PVA in places. Anyway, there it is, the mold ready for the next iteration.
What’s next? Well, I’m going to probably work on the radio tray and laying out some of the radio gear and some of the control lines. I’ll also finish up the mast rigging by creating the jib boom and working out the geometry of the jib connection points on the hull. I haven’t figure out exactly how I’m going to reproduce the NACA foil shape for the rudder…perhaps I’ll get thinking on that soon. However, judging from the puddle of water in our laundry room at the moment, it looks like I’m going to be installing a water heater tomorrow evening.
I’m still a bit delayed with the lead mold as my friend who does the CNC programming is on vacation at the moment. Just before he left, he was trying to get the mill run time down from the 32 hours per mold half predicted on the first programming pass! (I think the resolution was a bit high)
PS…by the way, that double fan in the window ($9.99 at Big Lots) shown behind the orange mold is absolutely terrific for evacuating the obnoxious vapors and dust from all this composite work.
I’ve made several key parts this weekend for the one meter and plan to start making a mold for the rear deck this evening (maybe). As I was uploading pictures, I was sitting here wondering why I’ve been having so much trouble getting the molds to release for some of these recent parts…wax….geeesh….I forgot the wax.
I’ve been putting in a lot of thought about how the controls for the rudder and sails might work. I like the looks of a big sugar scoop cockpit but it has some disadvantages;
It also has some advantages:
The solid flat top deck, while potentially drier, has a few disadvantages as well:
So I recalled an idea that Neville had a while back and decided to create a short sugar scoop at the transom that should provide a simple and robust method for accessing most of the controls. It will also firm up the structure in the transom for the backstay loads.
As I was making a trip across our plant yesterday, I saw them making several cuts of a solid round 3.5″ PVC so I snagged drop piece from the trash and proceeded to use it as a plug. I first attached a block of a 2×4 to the rear using screws – this would allow me to run the round stock squarely through my table saw by giving me two square sides. I setup the table saw to lop off a flat section and ran that through. Then I put about a 10 degree tilt to the bandsaw blade and made a cut on the end of the pvc. Then I sanded and rounded the edges, primered, wet sanded smooth, (forgot the wax), applied the PVA release agent, and vacuumed a fiberglass and epoxy layup around it. This morning, after it soaked in water all night, I finally was able to separate the two – but the plug would need to be completely refinished if I planned to use it again (no wax…so it pulled the primer off with the part). However, I’m not planning on using that plug again anyway.
After marking it level and trimming up the part, I fitted a cut-out in the hull to the new scoop and tacked the scoop in place with some CA glue. I then mixed up a thick slurry of microballoons and epoxy, and carefully filleted in the inside of the hull to scoop joint. It’s curing out in the sun now, but I should be able to come back and sand everything nice and pretty-like this afternoon. I will then finish the rear of the hull here with primer and make a mold of the rear scoop and part of the stern of the boat. I will use this mold to make the future scoops so they will simply have a lip that fits right down over the transom making installation on future boats a snap.
So what does this do for me? Well, I’ve got some ideas about how the sail control lines will come out of this – but I’ll cover that in detail when I get to it soon. The biggest thing this does for me is keeps me from having to build another hatch to access the rudder hardware. Since the floor of the scoop will function as the upper deck for the rudder post, I no longer need to install a rear subdeck to support the rudder post. I also don’t have to create a second water-tight hatch and the rudder post will be sealed on the top and bottom so the chances of it leaking inside the hull are very small. It also makes the rudder easily removable for transportation and storage without the need to open and reseal anything. I believe the rigging is going to be pretty neat too…stay tuned.
