Mauro,

Yes, I’m hoping that we can develop a library of 3D printing files, for use by any member, anywhere in the world. It has to be somewhere that can accept all the file types in use: STL, 3MF, G-code and so on, and I don’t know whether the Wild Apricot will do that. Our ‘Box’ storage should be OK though. 

Here’s another idea for a masthead to be bonded onto the 76mm diameter top of a tapered tube. It’s in two parts, both 3D printed in black ASA plastic, chosen for its mechanical properties and UV resistance.

The lower part has 12 radiused holes - choose any of them to drill through the aluminium tube, either singly, to tie a stopper knot on the end of a 4mm or 5mm Dyneema line for topping lifts, or an adjacent pair, to tie stopper knots on the ends of a short Dyneema loop to which a halyard block can be shackled. The stopper knots are thus hidden tidily inside the mast tube, which is bearing all the tensile load. The masthead is only there to provide a smooth radiused exit, and bears very little load. 

The upper part is fastened on by three M5 countersunk screws, and has a plinth onto which a tri-white nav light can be screwed. There can be a number of different upper parts, each with fastening and cable holes already in place to suit different brands and models of lights; and also of different shapes (not circular), so as to mount a wind instrument and/or a VHF antenna.

Hi David,

I'm sorry if I made the impression that I consider moulding always superior to direct print. That's not my point. I just wanted to add more applications/ideas to the pool, as a plus to what you and others already gathered as ideas.

Yes, low stressed parts, especially when under pressure load like batten ends, mast wedges, etc, will be perfectly fine if direct printed.

I would be sceptical about the mast collar from an elastic direct print. For this case I think casting liquid silicone or PU (elastic) into a 3D printed mould (similar to injection moulding) would be my choice if I would aim for durability. There's only one way to find out, and I hope that you proof me wrong.

Masthead: depending on the design, there's lots of bending and tensile loads. Hmm, hmm, not really advantageous for printed thermoplasts. But as always with new tools at hands, the design of a part needs to change according to the characteristics of that new tool. So you might possibly design a masthead which takes the pros/cons of printed thermoplasts into account, and make it work!

If you compare the datasheets of fibre inforced filament to actual grp/crp, you will find it is two different worlds. Yes, fibres add to the strength of the filament, but it still stays very short fibres in a thermoplast...

Looking forward to new experiments, designs and ideas!

Cheers

Paul

Hi David,

congratulations for discovering 3D-print. It is a tool with a huge scope of application.

In my actual job as development/mechanical engineer I print about 2 – 3 parts every day. We have 5 printers at work, two of those are FDM-printers (like the one you posted) and three are SLA printers. SLA uses liquid resin which is hardened by UV-optics and really is another world, regarding speed, accuracy and material choice. But it comes at a price which is not feasible for most private uses. FDM printers are fine, too, just slow and limited when it comes to strength of the parts. 3D-printing so quickly got standard in mechanical engineering, that I can hardly imagine how it was before they’ve been around… Beeing able to design my parts, hit print and three hours later I can check with my own hands what I before designed in CAD – that’s amazing. Of course, that’s only for prototyping. I can imagine a lot of applications for the junk rig, and you already have plenty ideas :-)

Just to throw in some thoughts:

Instead of using the printed parts - where you are limited by the limited properties of “printed” PLA, ABS, PETG and the like – you might want to consider to use the 3D-printer to build moulds. Such a printed mould does not have to be so strong, but can be used to laminate grp parts and cast rubber/silicone parts. It if of course important to wax the printed mould (candle wax is just fine), to be able to remove the casted/laminated parts.

For example: the circular mast wedge and the mast collar you posted recently could be casted by 2k-materials into a 3D-printed mould. That way, you are not limited to what material your printer is able to work with and not limited to the reduced strength of layer printing (which is not as good as advertised, especially with flexible material…).

Another example: Three years ago I printed a simple mould for Ilvy’s anchor locker lid. It had no exit hole for the anchor chain, and I didn’t want it to be open to the weather. So I clamped the mould to the lid, laminated, and removed the mould. It worked like a charme.

One junk rig related part I am constantly juggling in my head are laminated hinge cones for the wing sail (yes, Ilvy needs one!). With a 3D-printed mould, which can be repeatedly separated, it should be possible to laminate these cones from carbon, keeping them light, strong and cheap. I imagine using an inflatable positive cushion, onto which the wetted carbon layers are arranged. Then the 3D-printed negative mould is fastened around it – and the cushion filled with pressurized air.

I wish you some good and nice hours digging into the 3D-printing world. Looking forward to some fascinating ideas from you!

Cheers

Paul

How about this for a very simple item to print? A circular mast wedge with a slot in it so that it can be easily slid onto an aluminium mast. The material, diameter and cone half-angle can be adjusted according to the requirement. This example is for a 200 mm diameter mast, the height is 100 mm and the half-angle is 5˚.