Boat hulls built with DuFLEX Composite panels are inherently smooth, so fairing should be minimal.
There are several methods of fairing, but two that ATL recommend are
- Make temporary battens of thin plywood or laminate, about 25mm wide, and tack them at even spaces around the hull. The battens should be covered in plastic packaging tape to avoid inadvertent bonding.
- Screed fairing compound in between the battens with a trowel. Take a 5mm * aluminium batten 50mm wide, the length of the spaces + the vertical batten width, with a fine edge on one side and press the ends firmly onto the timber battens and drag it downwards over the compound on the side of the hull. This takes off the high spots and levels the fairing compound to the height of the temporary battens. *Curved areas will require a more flexible batten, similar to the ones taped on the hull.
- Remove the temporary battens and allow the compound to cure completely.
- Sand the batten space to bevel the edges and fill the space with fairing compound to the same level as the main hull.
- Allow to cure completely, and then follow with standard final sanding and fairing steps. Alternately,
- Use the fibreglass tapes on the panel joints as a guideline to apply the fairing compound and screed horizontally along the full length of the boat in two applications. Allow to cure and do initial sanding and fairing.
- Follow with another full length run to cover the join. Allow to cure and then sand.
- Apply a final vertical screed to make sure all low spots are filled, prior to final fairing.
Once you have the hull nice and smooth, you will need to apply 2 coats of WEST SYSTEM® 105 resin / hardener mixture above the waterline and 4 coats below the waterline, to seal the fairing compound prior to applying primer / undercoat.
In all cases, the key is to screed carefully in the beginning to avoid extra work.
- ATL Composites recommends a mixture of WEST SYSTEM® resin / hardener and 410 Microlight Fairing compound as the best choice for minimum weight and ease of sanding. ** If the boat is to be painted a dark colour, 407 Phenolic Microballoons are the recommended fairing filler.