Pull/push pit mounting of Hella nav lights
- Thread starter infaddict
- Start date
infaddict
New Member
3D printing is a great shout and for some reason I didn't think of it! I'm a tech geek and been looking at excuse to buy a 3D printer for years, this could be it! And I dont mind the CAD side, I will learn that pretty quick.
Now to spend days researching 3D printers haha ;-)
Now to spend days researching 3D printers haha ;-)
justanothersailboat
Well-Known Member
I found another option for lights mounting which surprised me with how easy it was.
On eBay it's easy to get pieces of Acetal or a brand/variety of it called Delrin, flat sheet, in 10 or 12 or 15mm thickness. This is very strong stuff and yet is extremely easy to tap threads into. You don't need much tooling to work it, you can saw it, file it and scrape it or even put a smooth edge on with a low-angle block plane. You can't sand it. You can carve it with a "burr" tool in a grinder (but definitely not grind it!). I found it a really great way to adapt new lights onto old mountings or just onto the tubing. And it looks well done - nobody would know my mountings were bashed out in an hour or so in a rainy yard with very few facilities - and doesn't corrode. Most of my lights now use these not only to screw one thing to another (with threaded holes in different places) but also to route cables through grooves I dug in them, from where they come out of the new LED lamps to where I really needed them to be (eg inside a pushpit tube).
(It's also pretty handy as an intermediate where you need to screw something aluminium onto something stainless)
The two problems with 3d printing. One, doing CAD design for something you need exactly one of. Two, while some people have their home printing process dialled in well enough to make things that don't delaminate if left outdoors... it's not automatic. Neither insurmountable, but raises the bar for entry a bit. I tried 3d printing and see the use, but didn't end up loving it for these reasons.
On eBay it's easy to get pieces of Acetal or a brand/variety of it called Delrin, flat sheet, in 10 or 12 or 15mm thickness. This is very strong stuff and yet is extremely easy to tap threads into. You don't need much tooling to work it, you can saw it, file it and scrape it or even put a smooth edge on with a low-angle block plane. You can't sand it. You can carve it with a "burr" tool in a grinder (but definitely not grind it!). I found it a really great way to adapt new lights onto old mountings or just onto the tubing. And it looks well done - nobody would know my mountings were bashed out in an hour or so in a rainy yard with very few facilities - and doesn't corrode. Most of my lights now use these not only to screw one thing to another (with threaded holes in different places) but also to route cables through grooves I dug in them, from where they come out of the new LED lamps to where I really needed them to be (eg inside a pushpit tube).
(It's also pretty handy as an intermediate where you need to screw something aluminium onto something stainless)
The two problems with 3d printing. One, doing CAD design for something you need exactly one of. Two, while some people have their home printing process dialled in well enough to make things that don't delaminate if left outdoors... it's not automatic. Neither insurmountable, but raises the bar for entry a bit. I tried 3d printing and see the use, but didn't end up loving it for these reasons.
infaddict
New Member
Good shout. I am also considering very basic solution like a white piece of plastic (kinda like a chopping board thickness). That could be shaped and drilled very easily and would likely be weather proof.
justanothersailboat
Well-Known Member
Chopping boards seem to often be polyethylene with no UV additives and go flaky in the sun. Also, they usually need you to bolt through, rather than just tapping it (too thin and deformable to put a small machine screw in). The Delrin chunks cost more but enable some neater solutions... and so far they seem to last well.
DinghyMan
Well-Known Member
Chopping boards are usually HDPE, UHMWPE, or PE1000 all of which will creep under load and the common grades are not UV resistant and will degrade quickly in sunlight
Brass inserts put in with a soldering iron are a good way to put threads in Acetal or Delrin sheets
Acetal or Delrin (different materials) machine very easily and cleanly - just turn everything up to max and the chips come off like snow, not enough feed & speed and they give massive long strings which are a pain
justanothersailboat
Well-Known Member
A previous owner of my boat used layers of chopping board to make a pushpit bracket for the dinghy outboard, it didn't take that long for the sun to make it start to flake away, then I had to get rid to avoid spreading loads of plastic flakes all over the place. Definitely not the stuff for the job.
Interesting suggestion about the brass inserts DinghyMan, I know the ones. I am a bit wary of hot processes with either acetal or Delrin, but the temperature control of the iron should make that safe, I just tapped the stuff directly - seems to be much stronger than the case of the navigation lights, so strong enough!
Delrin and generic Acetal are different but very close relatives... I never found any of the differences mattering for this job or most other boat-parts jobs. Either of them is relatively expensive if you buy new, but loads of offcuts cheap on ebay. I wouldn't do that for some precision engineering part where known quality is needed, but for this it was fine, a 15mm thick chunk is so overbuilt. It all machines beautifully, but I suggested the stuff here because I was surprised to find that I could make these parts without access to machine tools. Makes it a more versatile option.
Interesting suggestion about the brass inserts DinghyMan, I know the ones. I am a bit wary of hot processes with either acetal or Delrin, but the temperature control of the iron should make that safe, I just tapped the stuff directly - seems to be much stronger than the case of the navigation lights, so strong enough!
Delrin and generic Acetal are different but very close relatives... I never found any of the differences mattering for this job or most other boat-parts jobs. Either of them is relatively expensive if you buy new, but loads of offcuts cheap on ebay. I wouldn't do that for some precision engineering part where known quality is needed, but for this it was fine, a 15mm thick chunk is so overbuilt. It all machines beautifully, but I suggested the stuff here because I was surprised to find that I could make these parts without access to machine tools. Makes it a more versatile option.
DinghyMan
Well-Known Member
The brass inserts go into predrilled pilot holes nicely with just a normal soldering iron, good thing is you can use a use a soldering iron to clean up afterwards if you get a bit heavy handed and both plastics can be formed and threaded using heat
You can buy a cheapy specialist tool for fitting inserts buts its just a soldering iron with custom brass ends for each size of insert, we have one and use it quite a lot, an alternative is to use the brass or stainless threaded inserts in pilot holes where the outside thread on the insert is coarse and grips well but needs careful predrilling
Delrin is very loosely just better quality Acetal and for most jobs the difference doesnt matter, one thing you cant do reliably with either is to glue them as almost nothing sticks to them for long, we sometimes superglue bits for machining and they can be just tapped apart quite easily without using any solvent
We did do some tests with some extremely expensive glue systems a few years ago but gave it up as unreliable - there used to be a 3M version of superglue for them but it was something like £275 a tiny tube
You arent kidding about it being expensive as its increased in price by over 200% in the last three years or so
You can buy a cheapy specialist tool for fitting inserts buts its just a soldering iron with custom brass ends for each size of insert, we have one and use it quite a lot, an alternative is to use the brass or stainless threaded inserts in pilot holes where the outside thread on the insert is coarse and grips well but needs careful predrilling
Delrin is very loosely just better quality Acetal and for most jobs the difference doesnt matter, one thing you cant do reliably with either is to glue them as almost nothing sticks to them for long, we sometimes superglue bits for machining and they can be just tapped apart quite easily without using any solvent
We did do some tests with some extremely expensive glue systems a few years ago but gave it up as unreliable - there used to be a 3M version of superglue for them but it was something like £275 a tiny tube
You arent kidding about it being expensive as its increased in price by over 200% in the last three years or so
slawosz
Well-Known Member
3d printing can be a way to go. PET-G is easy to print and cheap (£11-14 on Amazon for 1 kg) and will last for many many years. It is not only for making things, but for building templates and tools.