October 2004
The month for filleting.Devlin's lightbulb in a box idea to warm the resins works a treat. I've also bought some ±45° 150mm wide tape for the fillet reinforcement. The 0/90° I've been using up to now is probably fine but technically a poor substitute.
Devlin recommends that the fillet thickness be at least equal to the thickness of
the thickest panel to be joined. But there is no mention of the influence of the
included angle between the two panels. Clearly it can't apply when the panels butt
at 180°. If I allow the fillet thickness to decrease linearly with panel angle
I produce this family of fillet radii. Interestingly they produce roughly equivalent
fillet widths as well.
Or Graphically
Which is all very well until you examine the variation of included panel angle
along the hull.
So for the fillets with the greatest angle change over their length I made an
involute fillet template. You need to mark the fillet width on both panels otherwise
you don't know which bit of the template to use. As you slide along the fillet you
rotate the template to change the fillet radius and hence maintain the fillet thickness.
It takes a little practice and I suggest you make it from thicker platic than the 1.5mm I used.