PAR Posted July 29, 2015 Report Share Posted July 29, 2015 Feather the edges around the hole on the hull and apply a thin shim (thick paper, thin cardboard) on the mold, extending into the feathered areas a bit. This will make a dent, that will get filled with fairing compound without standing proud of the finished surface. I usually don't pother with mold release (PVA, etc.) on this type of mold, preferring to simply tape down the shim and mold surface with packaging tape. Quote Link to comment Share on other sites More sharing options...
Ken_Potts Posted July 29, 2015 Author Report Share Posted July 29, 2015 Hmm... I was planning to glass from the inside then pull off the mold and grind a channel into the joint on the outside for a final layer of biaxial but I like the idea of building a channel in beforehand with your shim. Thanks for the idea. Quote Link to comment Share on other sites More sharing options...
PAR Posted July 29, 2015 Report Share Posted July 29, 2015 Yeah, guess how I learned this . . . I use this stuff called "chip board" which is the cardboard you find on the back of a note pad. You can use it for lots of stuff, like planking templates for example. At the big box stores, they sell this stuff in a big roll, about 36" tall by a dozen or two yards. It's used to protect floors during remodeling and is often scored so it folds, cuts and tears easily. The brand I usually get is called "Ram Board". It's solid not corrugated, so it acts like sheet goods (plywood, sheet metal, etc.), making an ideal template material, before you commit to cutting up the good stuff. In your case, I'd cut the "shim" from this stuff. It's less than a 1/16" thick, so you don't need a gallon of fairing compound per square foot to fill it in. Quote Link to comment Share on other sites More sharing options...
Chick Ludwig Posted July 29, 2015 Report Share Posted July 29, 2015 Great tip. I'll remember it, too. Quote Link to comment Share on other sites More sharing options...
Action Tiger Posted July 29, 2015 Report Share Posted July 29, 2015 I sometimes use chip board when I need to glue two things together temporarily in models or miniatures. We build lots of fake stuff around here, see, sometimes small, and sometimes clamps are in the way. I'll have to go find a roll, as I've been using old wheaties boxes and the like, and all our notepads are floppy. 1 Quote Link to comment Share on other sites More sharing options...
PAR Posted July 30, 2015 Report Share Posted July 30, 2015 With some online searching, you can get unscored chipboard of various weights. It'll be on a roll if you're lucky and it's the stuff I use to make plank repair templates, when the old one didn't come off clean enough to to use as a template. It'll minic plywood or sheet metal in the way it bends and conforms to surfaces. I repaired a molded boat recently, needing to cut the outer veneers and chipboard worked great. Quote Link to comment Share on other sites More sharing options...
Action Tiger Posted July 30, 2015 Report Share Posted July 30, 2015 I use Bristol board sometimes for miniatures, and it sounds like this stuff on a roll could save me a fortune. I keep threatening to build another lapstrake canoe one day, too. Sounds like that stuff would be pretty neat to use to spile planks on for that, too. And stem and knee patterns. I do have a decent pile of crooks... Thanks for the tip. Quote Link to comment Share on other sites More sharing options...
PAR Posted July 30, 2015 Report Share Posted July 30, 2015 My last good use of this stuff was on a lapstrake. There's nothing better than being able to use a length of this stuff, to get out the plank template full length. No piecing or "tiling" stuff together just to hope things don't move. Place it on the building jig, lightly staple it if necessary, trace from below and you have a perfect template. You can also use a router from above, running a flush cutting bit against battens (the way I did it). No need to check it afterward, just trace onto planking stock and cut to the line. Quote Link to comment Share on other sites More sharing options...
Action Tiger Posted July 30, 2015 Report Share Posted July 30, 2015 Well, if I find some, I'll keep my compass, but I will kiss the luaun and carpet tacks goodbye! Quote Link to comment Share on other sites More sharing options...
Ken_Potts Posted August 2, 2015 Author Report Share Posted August 2, 2015 Earlier in this thread I posted a picture of my first successful eye splice in double braid rope (10mm polyester). I tested it last week by pulling it apart with a couple of trucks. The eye splice was placed over the trailer hitch of my truck and I tied a bowline on the other end and put the resulting loop over the trailer hitch of a co-worker's truck. First I eased my truck forward to tighten up the knot and the splice. Then I set the parking brake and my co-worker dragged my truck backwards a bit without hurting the rope. Next I stood on the brakes while my co-worker spun his wheels to no detriment of the rope. Finally he backed up a little bit and got a running start resulting in a satisfying SNAP! The rope broke (melted) in the tightest turn of the bowline. The test is not scientific (or even good enough for engineering in my opinion) but it gives me a warm fuzzy feeling that my splice was stronger than the bowline. The reason I went through all this rigmarole is that the genoa on my boat has been hanging up on the shrouds on almost every tack due mostly to the bowlines that secure the sheets to the sail. I have now spliced new sheets onto the clew of that sail and when we went out today we had not a single hangup. The pictures show the test setup (eye splice on the left, bowline on the right) and the broken rope. Quote Link to comment Share on other sites More sharing options...
PAR Posted August 2, 2015 Report Share Posted August 2, 2015 A bowline typically reduces line breaking strength by 40%. A figure 8 only 20% and one of the stronger knots. The blood knot, which is a common fisherman's knot is about 15%. Quote Link to comment Share on other sites More sharing options...
Ken_Potts Posted August 3, 2015 Author Report Share Posted August 3, 2015 I thought about testing with a stronger knot but since the splices were intended to replace bowlines I decided to just use a bowline. In the application (securing the sheets to the genoa) I was using a bowline rather than a figure 8 because it's easier to untie after loading - I won't be untying the splices, though Quote Link to comment Share on other sites More sharing options...
PAR Posted August 3, 2015 Report Share Posted August 3, 2015 Slices work well, they look more professional and they don't foul nearly as much as you've found. Good work Ken. Quote Link to comment Share on other sites More sharing options...
Ken_Potts Posted October 10, 2015 Author Report Share Posted October 10, 2015 I'm back at work on the repair finally. I had some difficulty with a "sandable" primer when I was trying to get the mold surface nice and smooth. Since I've got an impending Perth Summer breathing down my neck I decided I should get it in gear and get the hull repaired before the hot summer days set in even if the mold won't make a perfect surface. I have to paint the boat anyway so the surface is going to be sanded even if it ends up mirror smooth. I waxed the mold today. My primary goal with the wax is just to make sure I can get the mold off the gel coat once the patch is built up. I'll worry about pretty later. Here's a photo of the second coat of wax before buffing. Quote Link to comment Share on other sites More sharing options...
Ken_Potts Posted October 10, 2015 Author Report Share Posted October 10, 2015 Wait - That was the wrong picture. That was after buffing. Here's the "before" picture... Quote Link to comment Share on other sites More sharing options...
Ken_Potts Posted October 10, 2015 Author Report Share Posted October 10, 2015 I also finished grinding the interior of the hull. I took the flow coat and more recent paint off around the edges of the hole and I feathered the edge of the hole. Ninja or Zoidberg? You make the call! Quote Link to comment Share on other sites More sharing options...
Action Tiger Posted October 10, 2015 Report Share Posted October 10, 2015 Zoidberg. Ha. Man, you are a hoot! Quote Link to comment Share on other sites More sharing options...
Ken_Potts Posted October 13, 2015 Author Report Share Posted October 13, 2015 Before I removed the mold from the hull to fair and wax it I traced the outline of the hole onto it. That outline not only showed me what part of the mold needed to be faired, it allowed me to cut all 7 layers of glass to size pretty easily. I numbered each layer so I would get them in the right order and even more importantly so I won't try to install them backwards or upside-down. The dotted line is the approximate outline of the hole. Quote Link to comment Share on other sites More sharing options...
Ken_Potts Posted October 13, 2015 Author Report Share Posted October 13, 2015 I didn't quite manage to attaché the photo for the last post... Quote Link to comment Share on other sites More sharing options...
Ken_Potts Posted October 13, 2015 Author Report Share Posted October 13, 2015 Here's a view of the mold installed on the hull and ready for gel-coat. Quote Link to comment Share on other sites More sharing options...
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