Installing Bulkheads and Interior Furniture
Structural bulkheads will need to be bonded into the hull with a high density epoxy adhesive, such as WEST SYSTEM 105 resin / hardener thickened with 413 Microfibre Blend, and then fibreglass-taped into position. The weight and orientation, and the number of layers of taping, will be designated by your designer or naval architect.
Use a two-step bonding method for best results. There should be glue between the edge of the bulkhead and the hull. A generous fillet should run along the joint on both sides of the bulkhead.
While the epoxy fillet is still in the “green” stage for a primary bond, you can apply a fibreglass tape, wet-out with epoxy resin, along both seams. Multiple layers of fibreglass tape can be applied wet-on-wet, time permitting.
Non-structural bulkheads, with no loading, may be coved with a low density epoxy mixture and taped into position in the same manner.
Interior Furniture is much easier to make as modules on your work-bench, rather than inside the boat. Once the modular part is assembled, it should be dry-fitted to check the positioning and shape, then removed to the workbench to epoxy cove and fibreglass tape the joins, and to epoxy coat the surface.
For large curved pieces of furniture, such as cockpit or saloon seating, the DuFLEX panels can be kerfed to achieve the required shape. To make each of the radiused corners, run a portable circular saw against a plywood straight-edge, through the core to the inside of the outside laminate. The kerfs vary depending on the desired bend, so it is a good idea to draw the shape on the floor of the area it will be positioned and make a temporary jig of the curve required. To determine the distance between the cuts – look for the flat spots in the curve on the floor and measure.
For balsa and foam cored panels, a mixture of high density epoxy compound such as WEST SYSTEM resin / hardener and 413 Microfibre Blend should be spread into the open cuts: the panel is then bent over a temporary jig of its final shape and temporarily clamped until the epoxy cures. A layer of fibreglass of the same weight and orientation as the laminate on the panel should be applied to retain the full strength of the part.
Featherlight panels cored with paper-honeycomb can be kerfed with a metal disk for cutting stainless steel. The finer blade removes the requirement to backfill, and you can laminate a layer of fibreglass of the same weight as the original laminate to hold the shape.
Note: You will have much neater edges on the kerfs if you leave the peel ply in place when you are cutting.
Once the joints and taping have cured, the part can then be permanently fitted in the boat.
Edge detailing of exposed edges, in both interior furniture and bulkheads, will be required to complete the part. Edge detailing is the removal of the core on exposed edges of the parts, and replacing it with a low density epoxy compound, such as WEST SYSTEM resin / hardener blended with 411 Microsphere Blend or ATL’s pre-mixed Technifill R1170. A fibreglass laminate may need to be applied over the epoxy compound in the case of finishing a structural bulkhead, or for added protection of the edge – please refer to designer’s specifications.
To view a short video on edge filling with Technifill R1170, please click below.