Mini Drak Fins

thingiverse

I prefer printing my wing fins rather than relying on Coroplast. I opted to print mine using ABS on a 100 degree C bed covered with PEI and glue stick. A convenient alternative would be to use PETG. PLA doesn't hold up well in sunlight over the long term. If you're struggling with warped fins after removing them from the bed, try using a heat iron on high (for ABS) and slide it across the concave side of the warp. With some experimentation, you'll master flattening the fins. The large fin barely fits on my printer bed (as shown in the photo), so I recommend using a large printer to print this design - just slightly smaller than 12 inches square is required. I printed mine at a layer height of .2mm and a print width of .5mm. Additionally, I used 2 layers for the bottom and 3 layers for the top with 15% infill in S3D. This minimal setup keeps the part roughly watertight (or appears to be) while minimizing weight. With these settings, the large fin weighs about 24 grams more than the stock Coroplast fin of the minidrak. The good news is that if you can print this design, it looks much better than the Coroplast fins. By the way, my big fins are designed for Harvard Store's Oring wing joining method. So, the notch on the fin is a little taller and narrower than the stock Coroplast. However, it will likely work with the stock velcro method as well. *Update 6-2-2017: I've added split big fin files to print in two pieces on smaller printers. Simply sand them and use goop to join them. One set has notches for easy alignment and more gluing area, but may not look as nice.