This method is often employed by professional builders when vacuum laminating is to be employed but the project does not justify the cost of a production female mould. It might be used for a small production run or for just one boat.
A disposable male plug is built and faired, usually in customwood or mdf. The skin and core laminates are then laid over the mould under vacuum. This system is not often employed by
Infusion has become popular in production building because it ensures total resin penetration of the laminate. Infusion is technically exacting. It requires a purpose designed mould, careful
preparation for the laminating process, purpose specific materials and more setup time than other methods.
Infusion is only suited to production building unless the cost of the tooling can be absorbed in the total cost of a one off project.
BUILDING WITH FLAT PANELS
All boats have a large area in flat panels including bulkheads, floors, berth panels, cockpits soles and more. In addition many surfaces that are only curved in one plane can be built from flat panels.
The panels can be supplied in a Duflex kit specified by the designer, or they can be laminated and cut to shape on site by a range of methods.
Panels can save a lot of fairing work both inside and outside the boat.
Duflex panels are ready for resin coating and painting on the inside just as they come from the factory. The same can apply to on site vacuum laminated panels built on a glass laminating table.
In most cases external hull sides built with flat panels will require minimum fairing compared to other methods of construction, but especially so if the panel has been laid up on site with continuous laminates both sides of the core.
The image at right is a typical assembly diagram for a Duflex kit.
The advantage of manufacturing full size panels on site, in particular hull side panels that need to be very fair; is that the hull panels can be laid up in one piece without transverse joins in
the skin laminates that might require more fairing work than other build methods.
The process of building the panels requires a full length laminating table and the most suitable material for the table is safety glass. Surface preparation to prevent the laminate from sticking is just as important as making parts in a female mould.
Butt joins in the foam core are not likely to cause an unfairness in the panel, however avoiding painting the hull in dark colours is always good advice unless the materials and laminates have been designed specifically for the additional heat induced by a dark colour.
If the panel is wider than the roll width of the fabric then the first laminate can be rebated to avoid having a bump in the surface that will have to be faired. The joins at the top and bottom and ends of the panel can also be rebated.
The panels should be laminated under vacuum pressure or by using infusion. Apart from the requirement of the full length laminating table you need to be able to cut the panels to shape. There are three possible ways to do this.
1. CNC the panels on a full size cutting table. This method is only available to workshops that have large scale CNC facilities on site or can truck the panel from a nearby facility. It is the only way to ensure a high level of accuracy in the finished panel.
2. Lay up the panels slightly oversize, define the shapes from CNC cut vinyl or MDF patterns, and then rout the panels by hand. Vinyl is inexpensive and the patterns can be made on a printer at your local sign or graphics shop, however MDF has the advantage of being able to be used as a guide for the router.
3. Have the foam core cut to shape from the individual sheets. The outer skin laminate can be laid on the laminating table and cured, then the routed foam panels are vacuum bonded to the cured laminate, and finally the internal laminate laid over the core.
The result is a full size hull side panel that should have an A class finish on the side against the laminating table, and a good finish on the top surface which can be easily prepared for the boat interior.
Vacuum laminating of panels can be done by amateur builders but it does require practice and technical input from your materials supplier.
It will take some R&D time to determine the right resin viscosity, mesh size for the breather fabric and other details.
Don't make a large panel on your first attempt.
All of our designs are built on comprehensive 3D models which facilitate electronic cutting files for 2D and 3D components. You can use these files for the following purposes:
• To print full size patterns on paper, mylar film, or vinyl.
• To cut 2D shapes from composite panels or make templates and mould frames from MDF, Plywood or other materials.
• To make small parts with a 3D printer.
• To create plugs and moulds for large and small parts on five axis routers.
If you wish to build from a DuFLEX kit we supply the cutting files directly to ATL composites. If you need cutting files for other purposes contact us to discuss your requirements.
The combined Newsletter for Grainger Designs and Rocket Factory Trimarans
Our DuFLEX kit systems streamline the construction process for amateurs and professional yards alike. More details here…