It is the corections. The portside is still 100% good. Because of this separation of duties, the skins together can be less thick than the total thickness of its single-skin counterpart. Above: You can see the core (with checkered appearance) in this part, about to be vacuum-bagged at Sabre Yachts. Linear PVC is not chemically cross-linked and does not break when bent. Looks good! by topwater Sun Sep 16, 2018 7:40 am, Post A look at basic boat construction, fiberglass technology, and the fundamentals that modern boat builders use. The primary developer and major manufacturer of end-grain balsa core is Baltek Corporation of Northvale, NJ. Tension and compression are generally easy to visualize. SAN foam is a new core material that has been developed since this article was first written ten years ago. Most sailboats racing IMS, PHRF, and one-design are built with at least one kind of core in their hull and deck laminates, and for good reason. What do you use to bond the core?? A thin skin can bend out of line so much that it breaks away from the core, causing radical delamination. Environmentally responsible, SCRIMP(tm) is a completely closed system that traps VOC emissions instead of sending them up the stack. You must look at the total ply stack of the laminate schedule when comparing core and laminate weights, strength, stiffness, and cost. by Jaysen Sun Sep 16, 2018 7:07 am, Post Different density and or thickness will determine how long it takes. These subdivide the hull laminate into panels. More glass and more epoxy!! Welcome to Yrvinds website: small boat designer, builder, sailor & writer. Top 10 Choices for Boaters, Fiberglass Repair, Epoxy, Resin, and Help, Factory Fridays: Cigarette Racing Team's Boat Building Process - EP. Advantages of Epoxy Composite Construction, Nomex, with aramid fiber, is made by Hexcel Composites, Dublin, CA, Plastic, Nida-Core, from Nida-Core Corporation, Hoboken, NJ, Paper, called Tricel, from Tricel Corporation, Gurnee, IL. Something Good is Brewing in the Sportfishing Community, Introducing Afuera Coffee Co. Google Because the SCRIMP(tm) system achieves equilibrium resin content (50% to 70% fiber weight, depending on fiber architecture), unlike most composite processes, it is inherently repeatable. Instead I chose the bricklaying method, building the boat of small bricks or tiles or quadrangels of Divinycell. If paper core gets wet, it goes all mushy, just like cardboard left out in the rain. 8, Twin Vee PowerCats, How to Buy a Boat: Tips for First Time Buyers. I wont go over 20.. the other guy is around 15 gallons in and hasnt built a cap yet. Above: The development of serious speed boats, like this Mystic catamaran, played a significant role as manufacturers learned how to minimize weight. They must be perfectly sealed against. For more than 30 years Divinycell has been the first choice of leading producers of sandwich composite structures around the world. Many people wonder how modern fiberglass boats are built, and boat building today is not at all like it was back when antique and classic powerboats were built. And because cores are very lightweight, the cored-skin laminate weighs less than the single-skin laminate. Used 2x epoxy and did 12oz bottom. When the glue had set. Au-Struck: A Journey Along the East Australian Current. SCRIMP composites, with or without a gel coat, exhibit near-perfect surface quality. You can thermoform divinycell. Builders use the moisture resistant qualities of epoxy to take advantage of wood's strength, stiffness, light weight, resistance to fatigue, insulating ability, availability, cost, and beauty. All rights reserved. Post by Fuzz Thu Sep 13, 2018 9:31 pm, Post Follow the core manufacturer's instructions. The boat is unique. Is divineycell foam same, better or worse? An air suction pipe is installed into the bag, and the air between the bag and core is sucked out through the pipe by a vacuum pump. SCRIMP(tm), unlike prepreg, does not require refrigerated storage, time-consuming debulking, breathers, bleeders, and porous releases, or the scrap associated with bridging. It is closed-cell polyvinyl chloride, was and still is one of the best of all foam cores. The problems of rot and softening were replaced by hydrolysis, blisters and delamination. The ply version only uses tape for seams, no ply skin. Cores, however, must be quite thick, and so the total thickness of the cored-skin laminate is more than a single-skin laminate. Under these loads, the panel bends and experiences stresses within the laminate. Generally, you cannot isolate the core out of the laminate for comparison. Direct fiber placement of material to each specifically designed molded part is assured. Next step is to shape the foam. Diab Inc. markets putties called Divilette (for Divinycell), K-Lite (for Klegecell), and ProBond (for ProBalsa),. Panels are usually analyzed by looking at a strip of laminate that is the shortest distance between two internal structural members such as longitudinal stringers or bulkheads. Nails and screvs are removed. Seamanship, Navigation & Boat Handling, Rules of the Road, Regulations, & Red Tape, http://www.fiberglasssupply.com/pdf/moformDiab.pdf. This leads to serious blistering, delamination, and even considerable weight gain, particularly in honeycomb hulls where water can fill up all the open cells. It has been edited and updated to reflect some of the latest core material technology. Plywood can at least do single curvature reasonably well, but cant do compound curves. Twitter. Most widely used throughout the world, balsa core is made with the wood grain running from skin to skin and is termed end-grain balsa. Above: From innovative marine propulsion systems and cutting-edge onboard technology, to the advanced physics of computerized hull design, boat builders share their fascinating stories and unique approaches to constructing and engineering a variety of watercraft in the Factory Friday video series from boats.com. boats.com, 1221 Brickell Avenue, 23rd Floor, Miami, FL 33131, USA. Since cores resist shear stress, designers compare different kinds primarily by their shear strength and shear modulus. But i am going to use thickend resin. The SCRIMP(tm) process can be used to infuse thick laminates with the same high quality results as a simple 1/8" laminate. Ive seen no problems with them at all, and I have been assured that. garym, I agree completely with Fuzz!! The most common core materials utilized in building boat hulls and decks include balsa wood, PVC (polyvinyl chloride) foam, SAN (styreneacrylonitrile) foam, and honeycombs made from aramid (Kevlar), plastic, and paper. Workers can apply material to a mold much more easily when not encumbered by respirators, gloves and resin suits. Composite construction includes a variety of building methods that use epoxy to protect the materials from moisture as well as hold the materials together. Before it cures, they press the core blindly into the wet laminate. These days, boat building is actually pretty high-tech. Void-free surfaces do not require filler in painted applications or expensive rework associated with "egg shell" effects. Photo by Bavaria Boats. In boats.com's Factory Fridays video series we tour boatings top manufacturing facilities across America. Just enough wet fiberglass or bonding material must be used for a good bond, but excessive amounts of resin will fill up the honeycomb cells, making the boat way too heavy. The development of fiber reinforced plastics (FRP) offered apparent solutions in new materials and techniques. High compressive properties are necessary to resist the crushing loads of through-bolts wherever hardware such as winches, tracks, and cleats are mounted. Below is some text, courtesy of Tillitson-Pearson regarding the scrimp process they developed in the mid eighties. The bond of the skins to the core must be perfect. Also, thin skins tend to buckle as the laminate bends. Then vedges were glued betveen the quadrangels, held in place with nails untill the glue set. Above: In the modern age, building a boat begins with a mold. Divinycell is available in different grades--I think from memory the orange coloured stuff is the best. Photo by Regulator Boats. A boat's hull laminate is stiffened by internal members such as bulkheads and longitudinal stiffeners. All Rights Reserved. Because lay-up is performed with dry materials, workers are not exposed to wet resin. In most cases, all cores can be made to do the same job. In general, balsa and aramid honeycomb are stronger and stiffer in shear than the other core materials. SCRIMP(tm) saves labor and time with dry lay-up. Depends on what application you using Divinycell for. Polyester resin composites are porous, so water can readily seep into the laminate by osmosis. Please support our sponsors and let them know you heard about their products on Cruisers Forums. Boat Building general. densities being the most common in boat building. by fishgitr Sun Sep 16, 2018 3:31 pm, Post If youre talking about a transom, more like ply wood. How thick should the core be? The resulting structure has physical characteristics superior to the components by themselves. However, as with wood, polyester resins have been plagued by the effects of moisture penetration. The choice as to which core is best for a particular design usually reduces to which core is the least expensive for the greatest strength and stiffness. My 1989 Swan 43 has Divinicel cored decks (and longitudinal hull stringers). You need at least twice the amount of glass and epoxy on a foam cored hull. All rights reserved. I too did more layers of glass than what would be used on wood. ft. to 25 lbs./cu. They bond exceptionally well to a wide range of materials and are highly moisture resistant. Composite construction has proved itself at the top levels of competition in sail and powerboat racing, in the harshest environments and under the toughest working conditions. The pattern was tried for accuracy and corrections were made, then the Divinycell quadrangel was cut out and hold in place with temporary scruvs. The thicker the core, the thinner the skins can be, and so the lighter the laminate. For a non-stop sail of one year the boat has no other choice than to be heavy. Questions before purchasing the plans and announcements.. Cracker Larry's Corner: Boat Repair and Rebuild Support, Core Materials: Plywood, Foam core and Honeycomb, Builders' Tips, Tools, and Tricks of the trade, Builder's Progress and non technical messages. To vacuum bag a core, laminators first lay a bleeder cloth over the core, and over that they drape a large sheet of plastic film the "bag" and seal its edges all around with a special thick, sticky, sealing tape. Like mechanical properties, prices go up with increasing density. My v12 was my first build. Epoxy resins, the key ingredient, are among the most versatile of thermoset plastics. WHAT IS EPOXY COMPOSITE CONSTRUCTION? Properties are from manufacturers' published data for approximately 6.0 lb./cu. SCRIMP(tm) involves using a vacuum to force resin through a laminate at a controlled ratio. Please do not compare the amounts of glass and resin for a plywood core to a foam core. Balsa core and the higher densities of Divinycell and Klegecell have sufficient compression properties to resist such crushing loads, but the other cores must be removed and replaced with solid wood or structural putties in areas where through-bolting occurs. It comes in only two densities, 3.8 and 5.5 lbs./cu. It is a mistake to design and build skins that are too thin. Can Divinycell be used in place of marine plywood for the V12? Designers, builders and owners have more choices available. Nice work. There is no other choice. By understanding how a boat's structure is designed and how it works, you can compare these core materials for yourself. ft. density. Of course a quadrangel can never be trusted therefore they were turned into triangels always reliabel. Stiffness means the hull does not flex out of shape, which would increase hydrodynamic drag and slow the boat down. How to Buy a Boat: Tips for a First Time Buyer, Top 10 New Fishing Boats for Under $20,000, What Type is Right for You? I took measures from the moulds. VERSATILITY The builder using composite technology can build boats with a range of materials, designs, and construction methods that are perfectly suited to the boat's use and the customer's needs. A rough provisional estimation of the itinerary for my Cape Horn doubling. A pattern was made. The Mountain Bike of the Oceans. In glass laminated boats, epoxy's superiority to polyester resisn as a stable moisture resistant adhesive reduces the possibility of delamination and gelcoat blistering caused by moisture penetration. Everything from strip canoes to work boats, high performance multihulls to offshore racing powerboats have been built using epoxy composite construction. Can anyone give me the pros and cons of divinycell foam, Location: Thunder Bay, Ontario - 48-29N x 89-20W, Look at any penetrations of the cored areas. This makes the cored-skin laminate stiffer. Although many modern boatbuilders eschew the use of wood, on high-end custom yachts like this Jarrett Bay, methods like cold molding are often considered superior to more modern techniques. Engineering can check fiber orientation prior to infusion. Basically, it combines the linear, non-brittle features of Airex in a broad range of densities like Divinycell, from 3-12 lbs./cu. I have therefore developed a unique building method. Each kind of core requires slightly different laminating techniques, and different building crews tend to have developed their own preferences. Cores make the hull of the boat stiff and light. ft. Honeycombs used to be pretty expensive (some still are), and as such, were rarely used in production boats and only in the most expensive one-offs. Cross-linked PVC cores are Divinycell and Klegecell, both marketed by Diab Group of DeSoto, Texas. Lightness means less weight to move through the water, so speed is faster. The deflection of the strip is greatest in the middle, but the stresses there are only half what they are at the ends of the strip. Builders developed sophisticated wood construction methods, but never overcame wood's susceptibility to rot and significant maintenance requirements. Boats up to 15' for oars, power or sail. Use the core only as the manufacturer intended it to be used. With honeycombs, particular care must be taken with the bond surface because the skins bond only to the paper-thin edges of the honeycomb cell walls. Its just a bit more work into filling the scoring with thickend resin (not thick like faringcompund, just lightly thickend). The panels of a boat's structure must be designed to withstand a number of different stresses. The leading brand of linear PVC core is Airex, marketed by Baltek Corporation. Questions before purchasing the plans and announcements.. Cracker Larry's Corner: Boat Repair and Rebuild Support, Core Materials: Plywood, Foam core and Honeycomb, Builders' Tips, Tools, and Tricks of the trade. To achieve total contact between core and outer skin, most builders nowadays use vacuum bag techniques, employing the same sealing principle that keeps packaged bologna fresh in the supermarket. Not only does this eliminate the need for masks, gloves, and protective clothing, but it means a cleaner, healthier production setting and environment. In fact, measured levels of VOCs are lower than 10ppm. Paper core is becoming increasingly common in boat interior joinery, but is not recommended for hull and deck structures. by Jeff Fri Sep 14, 2018 8:02 am, Post It is available in a broad range of densities, from 3 lbs./cu. Jeff. The worst loads are imposed by wave impacts against the sides and bottom of the hull. It is impossible to bend that kind of Divinycell into that shape. Unlike RTM, SCRIMP(tm) requires only one tool side in conjunction with a flexible bag. Properties vary significantly with density the denser the material, the stronger and stiffer it is. Use proper engineering and design procedures. I agree with too as you will use more glass. In summary, core materials make boats stiffer and lighter.