A selection of surfboard plugs for attaching a surfboard leash to a surfboard. The _thin file totals 13mm depth, while all the other ones have a depth of 15mm.

Doesn't Matter

Doesn't Matter

0.2 - 0.3 mm

80 - 100%

For best appearance - print as oriented in the STL. Just remember that prints tend to be weakest along the layers so a hard pull on the leash will apply most of the stress on the weakest characteristic of the part.

For best strength - flip on it's side and print with support. It might not look quite as nice though.

Whatever you do with the printing, make sure that there are loads of solid layers on the top as you'll likely be sanding slightly into the surface of the part after glassing the plug in.

I'll be aiming for big overlaps between infill and perimeters and printing with solid layers every so often just to ensure that it's well sealed. There shouldn't be any real need to completely seal the unit for waterproofing if your resin pour is effective -- but it can't hurt, just in case.

Finally, just consider the temperature characteristics of the plastic that you'll be using before glassing it into your board - boards can get hot in cars which could be trouble if printing in PLA, and, if using a polyester resin for glassing the plug, well, maybe just don't. The curing process is exothermic which could be interesting - if you do though, let me know how it goes.

For best results I would use a 3mm DIA x 30mm smooth hardened stainless steel rod with this part to ensure no rusting - or something with similar strength & durability characteristics. Tolerance on the hole for the insert has to be pretty close to stop any resin flowing through gaps and filling the recess so you'll probably need to heat the rod and work it in.