Wooden Boat Restoration Repair - WEST SYSTEM Epoxy

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2.1.2 The skin One of two basic types of skins covers the hull and deck structure, providing a watertight membrane. Variations of planking provided the only alternatives for covering wooden structures for thousands of years until modern adhesives made the plywood skin more common and more durable. Planking Planking, whether carvel or lapstrake or a variation of these, is more susceptible to flexing and leaks than plywood. The individual planks run generally parallel to the centerline of the boat (Figure 2-2). They rely on fasteners at each framing member and the caulking to resist shear movement (the slight sliding movement between planks when a hull twists). In lapstrake planking, where each plank overlaps the preceding one, clinch fasteners or screws along the lap serve to tighten the lap and resist shear along the lap. Joints between carvel planks were traditionally sealed with cotton and/or oakum caulking driven into the seams with a caulking iron and filled over with tar or flexible sealant. Driving the caulking into the seams helped to stiffen the boat initially, but caulking needed to be redone as the boat’s fasteners worked and the planking swelled or shrank. Double planking was usually two layers of carvel, or square seam planking, sealed between seams and layers with shellac, paint, bedding compounds or glue. Occasionally canvas, bedded in paint or white lead, would be used between the planking layers. Figure 2-2 Typical laid plank deck and carvel planked hull. Figure 2-3 Typical plywood construction. Inspecting and Evaluating 10 Plywood Plywood often replaces the many individual planks, greatly reducing the number of joints that are potential sources for leaks. The framework for a plywood skin is similar to the framework for planking. But, because the plywood is strong in more than one direction, the framework for plywood covered structures can be much lighter. The extra frames required in a planked structure to resist diagonal movement can be eliminated. The plywood sheets are usually glued to the framework and held in place with staples, nails or wood screws (Figure 2-3). Multiple layers of thinner plywood are used on surfaces with compound curves where a single thick layer can’t bend enough in both directions. Plywood can also suffer from moisture problems. Moisture can penetrate plywood through the end grain at seams, causing delamination. On the surface, moisture causes the top veneer to check. Early plywood decks were protected with canvas laid in a fresh coat of paint or canvas cement. The fabric may have offered some protection, but 2
ecause moisture can be trapped under a large area of the fabric, serious damage can be done before it’s discovered. When you notice the soft deck or the loose fabric, the plywood may have already lost much of its strength. Hardware Besides the problems of joints in the deck itself, deck hardware is a major source of deck leaks and moisture damage. All deck hardware is anchored to the deck with mechanical fasteners that penetrate the skin. Lightly loaded hardware may be simply screwed into the skin. Hardware items that take high loads need to be screwed or bolted through the skin into a structural member (e.g., a deck beam or extra blocking) that can transfer the load over a larger area. If all the mounting holes are not drilled precisely, the fasteners holding the hardware in place will not share the load equally. The hole with the most highly loaded fastener elongates as the hardware is stressed repeatedly. Movement reduces the load-carrying capacity of the wood fiber surrounding the fastener and creates an entry point for water. Bedding compounds, designed to seal out moisture between the hardware base and the deck surface, do nothing to prevent movement of the hardware. Over time, this movement will break down the bedding material and eventually allow moisture into the fastener hole. Moisture can quickly penetrate the end grain of the hole, weakening the fastener’s grip even further. This overview of a boat’s structure highlights some of the problems you are likely to face as a wooden boat owner. While these problems may be daunting, they don’t have to be fatal. One of the beauties of wood is its resilience. With a little resuscitation and the proper protection, your boat can begin a long and low maintenance second life. If you would like a more thorough discussion of boat structure, consult the books listed in Appendix–Additional reading, page 77. 2.2 Inspecting and locating damaged areas Inspecting and Evaluating 11 The first phase of repair involves inspecting and locating damaged areas. Even though damage may be obvious, finding all the hidden damage will probably require some dismantling. Because hidden damage from trapped moisture is a major problem with wooden boats, a thorough job of dismantling is important. A careful inspection will allow you to make better decisions about what repair procedures to follow as well as let you know just how big a job you are in for. Figure 2-4 Look for dry rot at joints and areas of standing water and poor air circulation. 2
Page 1 and 2: 002-970 Wooden Boat Restoration & R
Page 3 and 4: TableofContents 1 Introduction 1.1
Page 5 and 6: 1 Introduction Introduction 1 Since
Page 7 and 8: You need to decide the level of rep
Page 9 and 10: Introduction 5 The many joints in a
Page 11 and 12: 1.4.3 Ventilating for longevity Int
Page 13: Figure 2-1 Typical structural frame
Page 17 and 18: 3 Repairing Localized Dry Rot 3.1 E
Page 19 and 20: 3.2 Drilling and filling A common,
Page 21 and 22: Repairing the Structural Framework
Page 23 and 24: 5. Remove the frame from the jig af
Page 25 and 26: 2. Laminate a new piece slightly la
Page 27 and 28: 4.6.1 Repairing floors attend to. T
Page 29 and 30: Product tip—G/flex 655 Epoxy Adhe
Page 31 and 32: 5 Repairing Hull and Deck Planking
Page 33 and 34: 5.1.2 Filling the seams with wood A
Page 35 and 36: Figure 5-6 Replace a section of pla
Page 37 and 38: 2. Scrape the old paint and caulk o
Page 39 and 40: Place new layers ½" to either side
Page 41 and 42: 5. Clamp the sheet temporarily with
Page 43 and 44: 5 Bond the second layer of veneers
Page 45 and 46: 5.5 Installing a teak veneer deck R
Page 47 and 48: 6 Installing Hardware 6.1 Fastener
Page 49 and 50: 6.3 Casting epoxy bases for hardwar
Page 51 and 52: 3. Wet out the lower end of the stu
Page 53 and 54: Figure 7-1 Effect of color on surfa
Page 55 and 56: Figure 7-3 Roll lightly and randoml
Page 57 and 58: Safety 7.4.1 Surface glazing 7.4.2
Page 59 and 60: 8 UsingWEST SYSTEM Epoxy 8.1 Epoxy
Page 61 and 62: 206 Slow Hardener ® —Used for ge
Page 63 and 64: 8.3 Handling epoxy This section exp
Page 65 and 66:
8.3.3 Dispensing and mixing stroke
Page 67 and 68:
Additives Additives are used to giv
Page 69 and 70:
Product tip—G/flex Epoxy is a tou
Page 71 and 72:
8.4.3 Bonding with fillets Vacuum b
Page 73 and 74:
8.4.5 Applying woven cloth and tape
Page 75 and 76:
Using WEST SYSTEM Epoxy 71 Figure 8
Page 77 and 78:
Problem solving guide Problem solvi
Page 79 and 80:
Wood data Wood data 75 Wooden Boat
Page 81 and 82:
Additional reading Additional readi
Page 83:
Additional building and repair info
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Wooden Boat Restoration Repair - WEST SYSTEM Epoxy

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