Environmentally responsible, SCRIMP(tm) is a completely closed system that traps VOC emissions instead of sending them up the stack. Press J to jump to the feed. In small boats there would be no weight advantage and would cost more to build " more epoxy and glass ". Basically, it combines the linear, non-brittle features of Airex in a broad range of densities like Divinycell, from 3-12 lbs./cu. A look at basic boat construction, fiberglass technology, and the fundamentals that modern boat builders use. Thin-cored laminates generally have thicker skins, which means more fiberglass, more labor, and so more cost for the lay-up. With virtually no size limitations, the SCRIMP(tm) process can produce large and small components, as well as complex, multidimensional trussed parts. Then vedges were glued betveen the quadrangels, held in place with nails untill the glue set. The explosive growth of fiberglass-polyester boats over the last thirty years was built on the perception of low maintenance and easy fabrication. Cross-linked PVC cores are Divinycell and Klegecell, both marketed by Diab Group of DeSoto, Texas. Youd want an h200 or better for that application , and that stuff is dense. Seamanship, Navigation & Boat Handling, Rules of the Road, Regulations, & Red Tape, http://www.fiberglasssupply.com/pdf/moformDiab.pdf. Also, thin skins tend to buckle as the laminate bends. Twitter. Details can be seen of quadrangels and wedges and glue oozing out. What do you use to bond the core?? High compressive properties are necessary to resist the crushing loads of through-bolts wherever hardware such as winches, tracks, and cleats are mounted. The problems of rot and softening were replaced by hydrolysis, blisters and delamination. 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. The pattern was tried for accuracy and corrections were made, then the Divinycell quadrangel was cut out and hold in place with temporary scruvs. Measures were taken as good as possible. When the glue had set. I have therefore developed a unique building method. Cores are made from a variety of materials which have different strengths and stiffnesses. Follow the core manufacturer's instructions. Compared to polyester resins typically used in fiberglass boat construction, epoxies have greater strength, less shrinkage, better moisture resistance and better fatigue resistance. You must look at the total ply stack of the laminate schedule when comparing core and laminate weights, strength, stiffness, and cost. It comes in only two densities, 3.8 and 5.5 lbs./cu. THE EVOLUTION OF BOAT CONSTRUCTION For centuries, artisans shaped, fitted and assembled timber into wooden boats. The cross-linked is brittle and, if bent too much, it breaks. Divinycell foam are compatible with virtually all commonly used resin systems ( vinyl ester, polyester and epoxy) and has been used in land transportation, marine (pleasure, military and commerical) wind energy, civil engineering/infrastructure and general industrial markets. The inside fiberglass skin presents no problem when laminating because the laminators can see the core surface as they lay down the transparent wet fiberglass laminate. These days, boat building is actually pretty high-tech. I took measures from the moulds. In most cases, all cores can be made to do the same job. If youre talking about a transom, more like ply wood. Balsa, PVC and SAN foams require special putties to assist in bonding the core to the outside skin. densities being the most common in boat building. Chainplate popped out when sailing - what's next? The panels of a boat's structure must be designed to withstand a number of different stresses. Nida-Core has solved this problem with their polypropylene core by using a polyethylene film to fuse a non-woven polyester scrim to both sides of the core. All rights reserved. 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? The foam doesnt soak up as much epoxy as plywood. ft. PVC foam cores come in two varieties: cross-linked and linear (non-cross-linked). Properties are from manufacturers' published data for approximately 6.0 lb./cu. Top 10 Choices for Boaters, Fiberglass Repair, Epoxy, Resin, and Help, Factory Fridays: Cigarette Racing Team's Boat Building Process - EP. I too did more layers of glass than what would be used on wood. In general, balsa and aramid honeycomb are stronger and stiffer in shear than the other core materials. Note, too, that core mechanical properties increase significantly with density the denser the core, the stronger and stiffer it is. Designers, builders and owners have more choices available. 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. Just recently (late 1999), Baltek has announced the availability of SuperLite, a range of lightweight balsa cores from 4.9 to 8.7 lbs./cu. 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. Controlled bagging of performs and repeatable resin infusions enable any licensed fabricator to perfectly produce and reproduce specifically designed, high-quality precision parts with consistent dimensional accuracy. 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. And, depending on the engineering circumstances, a low-density, thick core could have the same weight as a high-density thin core for the same shear strength and stiffness. Ive seen no problems with them at all, and I have been assured that. 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. Unlike RTM, SCRIMP(tm) requires only one tool side in conjunction with a flexible bag. Workers can apply material to a mold much more easily when not encumbered by respirators, gloves and resin suits. The primary developer and major manufacturer of end-grain balsa core is Baltek Corporation of Northvale, NJ. It has been edited and updated to reflect some of the latest core material technology. A heavy boat with a lenght of ten feet or three meter must have very compund curves with small radiuses. Don't guess, have somebody with experience do the math. Divinycell is available in different grades--I think from memory the orange coloured stuff is the best. Plywood can at least do single curvature reasonably well, but cant do compound curves. Void-free surfaces do not require filler in painted applications or expensive rework associated with "egg shell" effects. Composite construction includes a variety of building methods that use epoxy to protect the materials from moisture as well as hold the materials together. LOWER MAINTENANCE All of the components in a composite boat are protected by an epoxy moisture barrier. 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. But a cored-skin boat designed and built with care will last for years, while you enjoy the extra performance and creature comforts. A boat's hull laminate is stiffened by internal members such as bulkheads and longitudinal stiffeners. My v12 was my first build. There is no other choice. The resulting structure has physical characteristics superior to the components by themselves. Corebond and a vacuum bag would work well if the shape was supported. Jeff. You can thermoform divinycell. Paper core is becoming increasingly common in boat interior joinery, but is not recommended for hull and deck structures. ft. to 25 lbs./cu. Technical Support Message Board and Builder Forums. They are made of a number of materials: Of these, Nomex is the most expensive and is used primarily in custom boats. Above: Overhead cranes are often used to lift major boat parts, like this hull for a Regulator fishing boat, out of the molds and into position for further assembly. In production boat building, the laminating crew lays the outside skin into a female mold first. How strong should the skins be? Delamination would be my worry. A HISTORY OF SUCCESS Epoxy composite construction techniques for boat building were first developed over thirty years ago. But i am going to use thickend resin. Under these loads, the panel bends and experiences stresses within the laminate. Is divineycell foam same, better or worse? Baltek supplies core in densities of 6.5, 9.5 and 15.5 lbs./cu .ft. Before it cures, they press the core blindly into the wet laminate. I wont go over 20.. the other guy is around 15 gallons in and hasnt built a cap yet. Builders developed sophisticated wood construction methods, but never overcame wood's susceptibility to rot and significant maintenance requirements. This depends directly and entirely on the size of the boat, the size of the hull panels, and the anticipated loads. 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. Each panel experiences water pressure and wave impacts from the sea. I am pretty much done besides a little fairing. Use the core only as the manufacturer intended it to be used. Like Copacabana I view divinycell as a plus. Please support our sponsors and let them know you heard about their products on Cruisers Forums. ft. All rights reserved. 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. A pattern was made. Welcome to Yrvinds website: small boat designer, builder, sailor & writer. Polyester resin composites are porous, so water can readily seep into the laminate by osmosis. 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. The worst loads are imposed by wave impacts against the sides and bottom of the hull. A rough provisional estimation of the itinerary for my Cape Horn doubling. Below is some text, courtesy of Tillitson-Pearson regarding the scrimp process they developed in the mid eighties. Stiffness means the hull does not flex out of shape, which would increase hydrodynamic drag and slow the boat down. This is a cockpit/wheelhouseroof where i had waterinstrusion and the woodcore more or less decomposed on the starbord side. Of course a quadrangel can never be trusted therefore they were turned into triangels always reliabel. Post by Jeff Fri Sep 14, 2018 8:02 am, Post Lightness means less weight to move through the water, so speed is faster. Boats up to 15' for oars, power or sail. 8, Twin Vee PowerCats, How to Buy a Boat: Tips for First Time Buyers. Properties vary significantly with density the denser the material, the stronger and stiffer it is. It is closed-cell polyvinyl chloride, was and still is one of the best of all foam cores. ft. density. With all my over build the completed hull is 150lb. The skins should be as thin as possible, consistent with strength, stiffness, ease of lay-up, and overall hull durability. You need at least twice the amount of glass and epoxy on a foam cored hull. The Mountain Bike of the Oceans. Since the moisture content is stabilized, the maintenance problems associated with wooden boats - rot, joint cracks, structural members swelling or shrinking, and surface checking - are eliminated. Photo by Bavaria Boats. Im doing it in foam and Im at just over 19 gallons. 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. 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. The Divinycell i bought frome store over here is prescored. Press question mark to learn the rest of the keyboard shortcuts. Direct fiber placement of material to each specifically designed molded part is assured. I divided the endships, fore and aft into a number of quadrangels. SCRIMP(tm), unlike prepreg, does not require refrigerated storage, time-consuming debulking, breathers, bleeders, and porous releases, or the scrap associated with bridging. In boats.com's Factory Fridays video series we tour boatings top manufacturing facilities across America. Used 2x epoxy and did 12oz bottom. Baltek's putty is called Baltek-Bond and is used with its balsa core products. By Eric W. Sponberg, Naval Architect The following article first appeared in American Sailor magazine. Finally, which core material is the building crew most experienced with? SCRIMP(tm) saves labor and time with dry lay-up. The putty is spread over the skin before it cures, then the core is pre-coated with resin and pressed into the putty. For more than 30 years Divinycell has been the first choice of leading producers of sandwich composite structures around the world. Composites can be uncomplicated structures of wood and wood veneer or complex vacuum laminated hybrids incorporating glass fabrics, aramid, or carbon fibers. As air is removed, the outside air pressure presses the core uniformly into the entire surface of the skin. Nice work. The ply version only uses tape for seams, no ply skin. This is because more labor is require to hand-select the correct densities of balsa stock to make up the core panels. By understanding how a boat's structure is designed and how it works, you can compare these core materials for yourself. Linear PVC is not chemically cross-linked and does not break when bent. Simply wet out the scrim and lay up your polyester or epoxy laminate directly onto the scrim. Cores make the hull of the boat stiff and light. The boat is unique. The basic guidelines that designers and builders must follow are: Most cored/laminate failures can be traced to a violation of one of these rules. by topwater Sun Sep 16, 2018 7:40 am, Post Powered by vBulletin Version 3.8.8 Beta 1. Its just a bit more work into filling the scoring with thickend resin (not thick like faringcompund, just lightly thickend). Minimal need for solvents reduces VOC emissions by as much as 90% over open molding processes. 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. Can Divinycell be used in place of marine plywood for the V12? Because lay-up is performed with dry materials, workers are not exposed to wet resin. Since cores are an integral part of the boat's structure, the designer must take proper account of these properties so that hull and deck laminates won't fail. Yrvind Ten with all the Divinycell pieces in place. SCRIMP composites, with or without a gel coat, exhibit near-perfect surface quality. The designer must solve this engineering problem for every single panel in the hull and deck. It is a mistake to design and build skins that are too thin. 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. Since cores resist shear stress, designers compare different kinds primarily by their shear strength and shear modulus. In fact, measured levels of VOCs are lower than 10ppm. Next step is to shape the foam. In a single-skin laminate, the outside surface is in tension, the inside surface is in compression, and the middle is in shear. Photo by Regulator Boats. Everything from strip canoes to work boats, high performance multihulls to offshore racing powerboats have been built using epoxy composite construction. Over the years, thousands of composite recreational and working boats have been built and the earliest are still going strong. Looks good! by fishgitr Sun Sep 16, 2018 2:26 am, Post They must be perfectly sealed against. Through epoxy composite construction, the builder can offer boats in a wide range of designs, materials and construction methods. Plastic cores are being used increasingly as structural cores in hulls and decks, and in interior joinery. Just wondering your method. It is available in a broad range of densities, from 3 lbs./cu. WEST SYSTEM and PRO-SET are registered trademarks of Gougeon Brothers, Inc., PO Box 908, Bay City, MI 48707-0908, U.S.A. Email comments or suggestions to webmaster@gougeon.com. A thin skin can bend out of line so much that it breaks away from the core, causing radical delamination. Photo by Mystic Powerboats. Idk another guy and I are both building the Conchfish. ATC Chemicals markets a putty called Core-Bond for their Core-Cell core. A stronger and stiffer core such as balsa can be thinner, and the weaker cores must be thicker. SCRIMP(tm) is a process called resin infusion molding. Copyright 1998. All Rights Reserved. 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. Note, however, that the heavier balsa core is less costly than the lighter balsa. Like mechanical properties, prices go up with increasing density. Videos about Exlexs sails and Yrvinds next design, Five videos presenting some of Yrvinds ideas. 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. Cores, however, must be quite thick, and so the total thickness of the cored-skin laminate is more than a single-skin laminate. 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. WHAT IS EPOXY COMPOSITE CONSTRUCTION? During this time, the properties of Divinycell foams have been continuously enhanced and improved so that it continues to be ideal for the vast majority of sandwich composite applications. 2022 Theriault Marine Consulting, LLC. A NEW INTEGRATED MATERIALS TECHNOLOGY Combining the best of wood technology with the advances in FRP materials and processes, leading builders have turned to composite construction to produce durable, distinctive boats. Use proper engineering and design procedures. If paper core gets wet, it goes all mushy, just like cardboard left out in the rain. A few words about why I chose the balanced lug sail. In summary, core materials make boats stiffer and lighter. Lenny is a graduate of the Westlawn School of Yacht Design, and he has won numerous BWI and OWAA writing awards. Epoxy resins, the key ingredient, are among the most versatile of thermoset plastics. Epoxy's excellent adhesion to balsa and plastic foam cores, glass, aramid and carbon fabrics, allows the builder the advantage of selectively integrating these materials into the boat's structure. Modulus means stiffness the higher the modulus, the stiffer the material. And then divinycell i biught has a mesh (net) on the side you cant see on the picture and its prescored so what i learnd is that it dosent need vacuumbaging, instead i will put a even pressure by putting weights on top of it all over the fomed area. Copyright 1999-2022 Boats Group. Thanks to cores, boats have better performance and enhanced creature comforts. The leading brand of linear PVC core is Airex, marketed by Baltek Corporation. Click on them once or twice to enlarge. Again, the designer must engineer the answer. Shear is the tendency of the inside and outside halves of the laminate to slide against each other in opposite directions. garym, I agree completely with Fuzz!! Photo Credit: Sabre Yachts. by fishgitr Sun Sep 16, 2018 3:31 pm, Post Please do not compare the amounts of glass and resin for a plywood core to a foam core. boats.com, 1221 Brickell Avenue, 23rd Floor, Miami, FL 33131, USA. How did you do the scoring on the foam? Me next to the boat. Twenty-five years of advances in construction techniques using epoxy-bonded materials have revolutionized boat building and set new standards for performance and reliability. 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. Leading builders are building stronger, lighter, more durable boats with epoxy composite construction. More glass and more epoxy!! Please include the boat type in your question. The weight of different cores is less important because they tend to be only a small portion of the total laminate weight. Any posts related to repair and maintenance, new builds, tools, sail making, boat upholstery, motors, electrical, hydraulics, plans, etc. This makes the cored-skin laminate stiffer. Finally, thin laminates are not very durable against minor impacts such as the hull bumping against a dock. Two densities of balsa are shown. The Divinycell i bought frome store over here is prescored and that makes the forming a nobrainer. Au-Struck: A Journey Along the East Australian Current. by Jaysen Sun Sep 16, 2018 7:07 am, Post by Fuzz Thu Sep 13, 2018 9:31 pm, Post Epoxy composite boats have set a standard for performance, reliability and beauty. They bond exceptionally well to a wide range of materials and are highly moisture resistant. You must also account for the weights of the skins that result from any given core material and thickness. It is impossible to bend that kind of Divinycell into that shape. are welcome. Divinycell H provides excellent mechanical properties to low Divinycell HM is designed with exceptional toughness for fast Divinycell HP offers elevated temperature performance with Divinycell PY is based on PET, which makes it a recyclable, 2022 ATL Composites. My 1989 Swan 43 has Divinicel cored decks (and longitudinal hull stringers). In a cored-skin laminate, the outside and inside skins experience the tension and compression stresses, and the core experiences the shear stress. Above: Two examples of fiberglass cloth: the fiberglass at the left is significantly thinner and lighter, but provides less stiffness. 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. This manner of bonding is very difficult to achieve on every single cell wall. by garym Thu Sep 13, 2018 4:54 pm, Post To contact me please phone as I dislike writing letters and e-mail. Note the small numbers at the edge of the pattern. Not only does this eliminate the need for masks, gloves, and protective clothing, but it means a cleaner, healthier production setting and environment. Nails and screvs are removed. I did not even consider it. The solution to these problems lies in epoxy composite construction. Epoxy provides a stable base for paints and varnishes, reducing the frequency of refinishing. 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. Diab also markets an end-grain balsa core called ProBalsa in densities of 5.6, 9.7, and 13.8 lbs./cu. 9, Factory Fridays: Twin Vee PowerCats Pioneers Boat Building Innovations, Understanding Foam Cored Boat Construction, Factory Fridays EP. SCRIMP(tm) involves using a vacuum to force resin through a laminate at a controlled ratio. The portside is still 100% good. Foam is really easy to work with too. These subdivide the hull laminate into panels. by jacquesmm Sun Sep 16, 2018 5:43 pm, Users browsing this forum: No registered users and 0 guests, Powered by phpBB Forum Software phpBB Limited, Style we_universal created by INVENTEA & v12mike, Facebook
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