Blackrock 24 (Build)

Discussion in 'Wooden Boat Building and Restoration' started by LP, Mar 12, 2013.

  1. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Using the dregs.

    I'm getting to the bottom of my first six gallons of epoxy. I've been pouring the dregs of mostly empty bottles of resin and hardener into my active bottles to keep the pumps primed. The last few batches were poured from the bottles straight into the mixing pot. I had opted to hold off on glassing some areas as my epoxy quantity was critically low and decided to stick with some initial wet out of plywood panels so I could stop at any point if the well ran dry, so to speak. Six more gallons is enroute, due to arrive in a day or two.

    My transom is finished and ready for installation when that time comes. I decided to use a 45 deg chamfer on the edged of the ply transom frame as it would be subject to getting wet in areas and I felt a chamfer would drain better than a radiused edge. By the time all was said and done, it would likely have not mattered. I left a square edge on the ply as the pilot bearing needs a place to ride or nasty things start to happen. This square edge needs a fillet to get my layer of glass to lay properly and chamfer or radius, there was going to be a fillet for the cloth to lay into (and shed water).

    Below is a little tool that I have found useful for making small fillets. It's sold for use with kitchen and bath sealants to make neat fillets with those sealants. It also does a great job for making nice neat fillets with epoxy. The rubber edges work like squeegees and clean up excess epoxy with no need for masking off areas. The second picture below is the thickened epoxy in place for filleting and the third photo is the fillet and surrounding area after a couple of passes with the filleting tool. Nice, clean and neat! :cool:

    IMG_2673.JPG IMG_2667.JPG IMG_2669.JPG

    The finished transom. The only thing I would do differently would be to use a radius (maybe) or break the upper edge of the chamfer so that the glass cloth would lay a little easier. As it was, it's trying to lift a little, but a touch extra epoxy at the chamfer kept any voids from forming. Time to put this puppy away for a while and stretch out both longitudinals. Oh, and the dark lines are where I couldn't quite get the rabbets/dados out of the stereo cabinet. A groove of less than 1/16" deep was left and filled.

    IMG_2677.JPG

    The board doubler. Weave filled and epoxy coated. Seems just a little scrape of thickened epoxy along the rouge glass edge is all that is needed to clean up that little tidbit. My concerns were unwarranted.

    IMG_2678.JPG

    Both longitudinals stretched out and being worked. Today is just some sanding and wet out of play panels. A cleat was added at the central cabin frame location. A simple piece of SPF 2x2 that will get a corner planed off when the epoxy sets. I find it easier to clamp a squared piece of wood and trim later than to try to glue a triangular piece of wood. In my efforts to not leave any screws buried in the build, I'm finding I am reluctant to even leave any screw holes from using temporary screws to attach components. Clamp it and trim it seems to be working well in most locations.

    IMG_2679.jpg

    Lastly, I've gone in and tapered my splice plates to remove some of their excesses. Most will be hidden, but a couple will have some visibility and the tapers will refine their looks a little.

    IMG_2680.JPG
     
  2. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Waiting for epoxy.

    Just a few shots. The longitudinals are completed so I took the opportunity to do a pre-assembly fit check while waiting for the epoxy shipment to arrive. Most interference problems were anticipated and local to spliced areas. The added thickness was not accounted for in my drawings and for various reasons, it was necessary to place two of the three splices in each unit at frame locations. These areas were trimmed and everything seems to be fitting together well. The rigidity of the longitudinal pieces, in the vertical plane, is incouraging. They are intended to play a big role in being part of the strongback during assembly. I was running short on time this day and was unable to properly fit the transom.

    Two views of the roughly assembled components. in these views, there are only six screws holding everything together. They are all in the central split frame. Four in the cross-pawl and one each side at the cleat on the longitudinal. All of the other frames interlock with the longitudinals. The transom is only sitting on the ground in the photos and will be raised 6-8 inches and raked aft.

    IMG_2684.JPG IMG_2687.JPG

    A view looking down the starboard side longitudinal. Aft of the V-berth bulkhead, the longitudinal forms one half of the CB box. It currently displays more curvature than it will have once assembled. This curvature will be shifted forward to the area where the hammer is hanging from the longitudinal. Curvature in way of the centerboard box was kept to a minimum so curvature was push for-n-aft to the ends of the boat.

    IMG_2685.JPG

    The epoxy has arrived and I am putting the finishing touches on the longitidinals. Mostly in the form of glass cloth in areas that will be subject to abrasion and also building epoxy coats. Ditto for glassing areas on a couple of the frames

    .
     
  3. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Critical Mass

    Well the shop has reached critical mass and something had to be done. All of the cut-off pieces of wood had to be sorted and tossed or saved. There was a massive pile under my make-shift work bench. I think this is one of the hardest tasks to do. It's hard for me to throw out any wood, but the smallest pieces. Excesses were thrown out and materials reorganized. Existing boats were rearranged and room was found to assemble components for the newest build. Ultimately, one of the boats will go outside. The powerboat will be the unfortunate candidate for banishment from the garage only because it is the most likely boat to find a standard sized boat tarp to fit it. Poor thing. :(

    To digress though, progress has been a little slow due to honey do's and holidays.

    These first four photos are a pictorial of scarfing my sheer clamps from 14' lengths of douglas fir. Six degrees gave me the scarf ratio I wanted. Yes the C-clamp crosses the blade path and I was vewy, vewy careful when I cut the scarfs. If I was doing a lot of cuts I might have opted for a less risky setup.

    IMG_2697.JPG IMG_2698.JPG IMG_2699.JPG IMG_2700.jpg

    The following pics are the final pre-assembly check of all of the major components before the actual epoxy starts to flow. Most items have seen a quick fit check, but the is the "it's for keeps" fit check. Also the broadstrake and sole panels have never been fitted so this is a check for them also. The sole panels fit between the longitudinals and fit flush across the bottom. They also define the contour of the logintudinals. The broadstrake (?) then lays on top (bottom) of the sole and gives a total thickness of 1 1/2" in the central portion of the hull.

    IMG_2748.JPG IMG_2746.JPG IMG_2740.jpg IMG_2741.JPG

    These lower panels were cut from the plywood stock in such a way that the butt ends were always the raw plywood end and the panels were made square to the plywood panel. The plan here was to have the panels self align when butted and become the guide for the longitudinals and all that attach then. The plan seems to be working as longitudinally, the boat is aligned to less than 1/16" error. That floats in my book.

    In these photos, the central box section, frames and stem are fitted and screwed into place. Today, the transom was fitted and the sheer clamps were rough fitted. The next work session will see the clamps notched into the frames and some knees and a breasthook fitted to complete the pre-fit stage. It's hard to believe, but the whole thing will come back apart to prep for glue and permanent assembly.
     
  4. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    I should never say that I'm going to do something because, then it doesn't get done. No breast plates and no transom knees got done. Instead, I had some alignment problems that I had to get sorted out. Strategic trimming to put pieces in their proper places took care of matters, but it took some time to figure out the offending elements. I also took some time to start cutting out furniture elements that will offer additional alignment help as they tend to "key" things in.

    One of my goals in this design is to attempt to reduce the materials required for the strongback and fixturing. The central portion of the hull(sole, broadstrake and longitudinals) form an integral strongback that keys and indexes the frames vertically, laterally and longitudinally. The primary weakness I'm seeing is the narrow footprint of what I've deemed the boxbeam. I plan to add "legs" to each frame out of 2x material that will index to a predetermined waterline and buttline, as much as possible, to provide the torsional stability is that lacking in my setup right now.

    Here are a few premadona photos with the interior pieces tacked. The photos have been flipped to appear right side up.

    IMG_2758.JPG IMG_2757.JPG IMG_2756.JPG

    I'm comfortable with the way things are lining up now so I have deconstructed a majority of the components and am preparing them for epoxy. All joint interfaces are getting a good 80 grit sanding and they will soon go back together with epoxy. You may have noticed some larger gaps between the frames and the vertical members they mate to. I originally scanted the longitudinals out of 3/4" plywood and cut the frames for the same, but after working all of the frames in 3/4", I realized the heft of the material and brought it down 1/2" ply. I also had concerns regarding it's ability to flex around the lower panels.

    This leaves me with a 1/4" gap that I think I can use to my advantage. I should be able to wedge the material in one direction, fill the joint with thickened epoxy in place, pull the wedge and have the epoxy squeeze out for the fillet. The opposite side can then be filled entirely with thickened epoxy or a shim can be inserted, wet with epoxy and filleted over.
     
  5. PAR
    Joined: Nov 2003
    Posts: 19,126
    Likes: 498, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Teething problems are to be expected, especially with mid stream changes, as you've mentioned. Nothing to worry about, that can't be accommodated with thickened goo. Once you have this assembled, you'll have a few dozen different things you'll want to do differently, in regard to the setup, strongback, etc. to make things easier, use less materials, reinforce areas, etc. - all part of developing an assembly process. Now you know why all designers are bald or nearly so at an early age. Keep up the good work.
     
  6. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Taping test.

    I've gotten the aft three frames located to my liking now. They support the cockpit seating and the upper edges of the frames in way of the seating are all co-linear(?). They are all aligned with each other and so are easy to tell if improperly positioned. I added support leg to the outer ends of some frames to stabilize things torsionally and I've cut out a few more interior pieces that will further stabilize and position the various components before the goo comes out.

    This build is bigger than anything I've done to date and I wanted to utilize materials and techniques that will result in a stronger build. Key to this was the use of bi-axial tapes instead of the woven tapes that I've used on my other builds. My desire was to use a 1700 45/45 biax in a single layer in most places and apply additional layers where needed in more highly loaded areas. I had concerns about a single layer of heavy biax vs. multiple layers of a lighter bi-axial tape. It was my fortune to be in a location last week where I was able to go to a fiberglass supplier and pick up a couple of yards of 50" bi-axial cloth(?). My goal was two fold. One was to determine whether I could successfully lay a single layer of heavy cloth and the other was to determine an acceptable method for slicing cloth into tapes.

    Digressing a slight amount, my search for biax tape was not entirely successful. I found various sources for these tapes, but the cost factor was either high or exorbitant. The lighter tapes were only a few cents cheaper a yard than the heavy ones so a double layer of light tapes was going to essentially cost twice that of a single layer of heavy. There are advantages to using multiple layers of light tape such as weigh savings, stronger joints even still and better load transmission by tuning the lay-up by varying tape widths and overlaps. This said, the simplicity of a single layer is also very desirable. Todays post is the process I've devised to make custom tapes for bi-axial cloth.

    I started by carefully rolling the bi-axial cloth around a broom handle to get a fairly compact roll of glass cloth. In this picture I'm rolling the cloth in a piece of contractor paper. Once wrapped in the paper, I continued to roll the paper repeatedly as every time the tube of cloth and paper made a revolution, the cloth was wound tighter and tighter. I was trying to compact the cloth as much as possible with out doing it any damage.

    IMG_2780.JPG

    Once wrapped, I taped the "tube" to keep it wound and added marks on the paper at 6" intervals for cutting 6" tapes.

    IMG_2781.JPG

    I tried a couple of different knives before settling on this one. I had to modify the blade on this knife before it would really cut properly. The straight of this knife didn't really cut the glass very well. I was thinking it needed a bit of a serrated edge. My solution to this was to take the straight edge and run it across my rough grind wheel.

    IMG_2782.JPG

    This was the result after the grind wheel attack and it was just enough for the blade to want to bite into the glass cloth.

    IMG_2784.JPG

    This is the resulting cut glass. The rough paper cut on the right side is from trying to use a box knife initially. A longer blade would be much more beneficial as it would allow for longer and cleaner strokes. I've got my eye on one of our kitchen knives that never gets used until it's the only one left, but it will be perfect once I put my custom edge on it.

    IMG_2783.JPG

    Multiple tapes each in their little wrapper after cutting.

    IMG_2785.JPG

    An unrolled tape. The cuts were actually very clean. The tapes are about 7-8' long. I'll be curious to see how big of a roll I can slice with this method. Also of note is the direction of the binding threads. I like that the binding threads run the lengths of the tapes as I feel that they provide continuity and stability of the tape while it's being handled in preparation for application.

    IMG_2786.jpg

    Lastly, the test joint. I made two different sizes of fillets in the event that one was too small. Both worked great though it took a little more effort and glue that a 6 oz. woven tape. It might be different for an outside corner, but these inside corners worked well.

    IMG_2788.JPG
     
  7. Sietse
    Joined: Jan 2014
    Posts: 21
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: The Netherlands

    Sietse Junior Member

    awesome project you got there!
     
  8. PAR
    Joined: Nov 2003
    Posts: 19,126
    Likes: 498, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    After giving it more thought LP, I've tried a way to cut (slit) some 'glass and the best method I found was a diamond blade on a angle grinder. I wrapped about 3' of 12 ounce biax around a 1" dowel, as tight as I could, then hit it with the grinder. Cut right through, clean. Of course, you've already made some cuts, but if you need more tape . . .

    On all cutouts and transition areas, I use a bullnose bit in a laminate trimmer. I just quickly knock off the edge or corner with this, before laying fabric. Your transom reinforcement looks like you got it stuck good, but this may not be the case always. I've also tried a cove bit to make smoothing fillets a really quick thing. That's hit or miss, depending on how steady you are, wielding an unguided laminate trimmer freehand, but I've found I can do 90% of the fillet length and finish up the corners by hand. I should add, it's helpful to be able to shape and weld cutting edges to your router bits, because these techniques will kill them pretty quickly. FWIW . . .

    Considering my intimacy with this design, it's darn nice to see her coming along. Most don't know how long you've been tinkering with this design, so the 3D views are rewarding. Keep up the good work.
     
  9. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Thanks for the words of encouragement, Paul. Thanks for the comment Sietse

    Major milestone yesterday. I started taping my frames to the longitudinals. No more disassembling. There is a boat being built in my garage!

    I'm finding out that bi-axial tapes are a whole other beast when compared to light cloth tapes. Wetting the tapes solely with a brush is tedious and time consuming. I ended up using a foam roller to speed the process. The fillets were put in place and before applying the tape I took the roller and applied a generous coat of straight epoxy on either side of the fillet. The biax tape was applied, pressed into place and properly positioned. The roller was used again to apply another generous coat of epoxy on the top side of the tapes. The 1700 biax is such a thick tape that it requires a generous application of epoxy to wet it out. It's also a fickle tape in some ways. With lighter cloth tapes, I could brush on the epoxy and the tape laid there nicely and was wet out in a few brush strokes. The biax lays in nice, but the thickness of it requires three times (?) the epoxy to wet out so it tends to pull up during the wetting process. Once saturated, it's a well behaved tape. Rolling the epoxy on either side of the fillet and then the tape itself, starts the wet out as some as the tape is put in place and it has the advantage of wetting the tape out from both sides. Once wet out with the roller is done, final wetting is done with a brush to get those areas where the roller missed like the fillet area. Also of note is the tendency of the tapes to curl. I think you can see it in the photo of a rolled out tape in my previous post. I laid the tapes into the fillets convex in the fillet and convex out of the fillet and decided on the convex out method. The curve is counter to the fillet, but tends to push the tape edges down rather than curling up. I liked the way the tape laid with the convex out so I chose to lay them into the fillets this way.

    Here I am wedging the panel away from the frame so I can wet it out with straight epoxy and then thickened epoxy. I think I could use only thickened epoxy as all parts are pre-coated and won't be any epoxy taken up by the wood. Since accessibility is somewhat limited, I feel better with a wet out of straight epoxy before adding the thickened stuff. The straight also encourages a bit of slumping in the fillets. but once the tapes are in place, everything stays put so I'm good with it.

    IMG_2789.jpg

    Looking down the storage area that will be under the cockpit. The aft two frames are taped. I have wax paper in the areas at the bottom(top) of the frames where I don't want any premature attachments. I needed to screw the sole into place so the longitudinals were proper contoured while the frame fillets cure.

    IMG_2791.jpg
     
  10. PAR
    Joined: Nov 2003
    Posts: 19,126
    Likes: 498, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Careful with wax paper, I've had contamination issues with it previously and I've also had go stick to it, amazingly enough. The exotherm is sufficient to melt the wax enough to get a bond and/or contaminate the surface.

    Instead of a brush, try using a plastic Bondo applicator. Inside corners require a brush, but not much else does and I've found squeegees and applicators work much better, without the waste. My process is to pour a line of goo at the bottom of a fillet, then drag it up, wetting the fabric as I go, moving excess around as necessary. I also scoop (sort of) goo with the applicator, by bending it a little between my fingers. Lastly, if you let the fillet coat kick a bit, so it's not wet but tacky, it'll hold the biax much better, as you wet it out.
     
  11. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Hey, Paul.

    I was in a rush and the wax paper was the easiest thing to grab. I only needed to protect parts from inadvertent contact with the goo. I wouldn't want to use it as a parting agent. Ugh!

    I like your idea with the pool of epoxy and the scraper. Scraping epoxy is the easiest way to go. Right now, there is no place to pool it (except on the floor :eek:).

    I really like the way a wet coat of epoxy on the substrate starts wetting the tape before any additional epoxy is applied. I've also started brush coating the fillet ahead of time. I can see where letting the epoxy go tacky would help, especially on overhead work.
     
  12. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    A couple of busy days in the shop. I've glued the sole panel to the longitudinals to make the central box beam of the structure. I did it in a two step process to make sure that nothing shifted on me. The sole is the soul of the boat in that everything builds out from it. It provides primary alignment of the hull and if it's out of wack, so it the whole boat. I chose to glue up the aft end first as it was the more complex problem. This picture shows the sole peeled up to provide access to internal structure and to trim a slight angle on its edges to give the epoxy more of a place to live. I angled the lower(top) edge in slightly so that when the panel was reinserted, not all of the epoxy would be scraped off as it would if the edges were square.

    IMG_2809.JPG

    Once the aft end was glued and screwed back together, the forward end was splayed open so epoxy could be applied there. The edges were left square here since the pieces would pull back together rather than sliding across each other. Sorry for the bad photo. No filleting was done as the goal was simply to get these major pieces glued to each other,

    IMG_2810.JPG

    Today's business was to fillet and tape everything that I glued yesterday. From the motor well to the v-berth, fillets and tape were applied. Only one side was taped in way of the cabin. The port side was taped while the starboard side was left alone. The starboard side is part of the centerboard box and as so, any filleting and taping would be undone when the centerboard slot is cut.

    IMG_2813.JPG IMG_2812.jpg IMG_2811.JPG
     
  13. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    I was looking at the overhead work with a little trepidation and debated putting it off until after roll over. The over riding factor in going ahead with the taping process was concern over the strength of the glue joints with out the fillets or tape to back them up. Fixing a broken joint down the road would be a real PITA. I chose a small seam to start with to see how things would go. Pre-wetting the surfaces to be taped was the trick. When pressed into place, the tapes stayed nicely in place for the rest of the wetting out process.

    I dropped out the aft cabin frame to give me free access to the under the foot well areas and this was a major boon to ingress and egress. Previously, I was getting into those areas with a creeper or through the storage access hole in the frame. A major obstacle to free access.

    I think that I have gotten over my price point issue with using a foam roller to apply epoxy. Maybe it's the size of the build or the use of materials that I have not used before, but they have been indispensable in applying the quantity of epoxy required for this thickness of tape. A note on economy though. I sourced a supplier of foam rollers that charges about a buck for a 9" roller. I cut them into thirds on my band saw for my 3" roller. Yesterdays roller lasted about 6 hours before it started getting hard and by that time I was putting the finishing touches on the last piece of tape for the day. These rollers do have a seam in them so they are not the best for finish work as the seam imprints the epoxy where it lands, but for these tapes, it's perfectly acceptable.

    One more thought on the overhead work. Once wetted out, excess epoxy would run down the vertical surface where it could be rolled out or scraped off rather than pooling in the tape had the joint been rotated 180 degrees.
     
  14. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    The transom is now a permanent part of the boat. Note the calibrated shim under the right hand support. :D

    IMG_2816.JPG

    The rudder port.

    IMG_2824.jpg

    The motor well to be.

    IMG_2821.jpg

    Fillet and taped at the end of the box beam.

    IMG_2817.JPG IMG_2819.jpg

    Next on the agenda is to attach the stem, to be followed by the second bottom layer.
     

  15. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Room finally.

    I had a weather window and I took advantage of it. The single digit temps broke and the snow stopped falling. The power boat went outside, the sailboat moved over and the lumber was restacked. It was time to stop trying to work around the obstacles in the shop and make the room that is needed to build. I stripped all of the forward frames off to allow the sailboat to be pushed away from the powerboat so the power boat could leave the garage. Then the sailboat was pushed over to the power boat spot and lumber was organized in a manner that the first wood to be used should be the most readily available.

    The current state of the build.

    IMG_2829.JPG

    After the reorganization, I spent some time prepping the remaining frames for installation. Mostly this meant sanding, sanding and more sanding. The new plan is to start with the aft most frame and install each frame working forward. Each frame will get referenced to those already in place. I nixed the plan to install stem next when I cleared out the shop. This plan is a little more straight forward with less repetitive steps.

    You gotta keep an eye out for munchkins in the shop. You never know where they'll pop in. :)

    IMG_2828sml.jpg
     
    1 person likes this.
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.