Which Plastic to Use?

[Norman_E]

I am pretty clued up on metals, but plastics I know little about. I want to make a new instrument pod to replace one made of thin plastic. I intend to make the new one out of thick plastic sheet, say 6mm front and back, with the edges from 16mm material. I have a choice of Nylon 66 sheet, or Acetal sheet. Does anyone know if either of these have good resistance to UV, as the finished pod will spend most of its days in the Mediterranean sun?

 

[colvic987]

Wouldn't it be easier to use fiberglass, make a wooden template of the finished article, smooth off using car body filler, then when happy with the plug, fibreglass it up, a lot easier than trying to get plastics welded up at joins etc...or buy a ready made off the shelf pod, like nasa clipper pod or the lewmar type, the latter expensive..

Plenty of informative videos of fibreglassing on youtube, if you have no experience, it is quite simple to perform a decent fabrication...

 

[dukes4monny]

I'm no expert, but a quick Google search turned up this info:
This site suggests that Acetal is not UV resistant
This site suggests that Nylon 66 has good UV resistance.

Dave

 

[Norman_E]

Thank you, Nylon 66 always looked the best bet. I particularly did not want to make the pod from fibreglass I have never liked working with it. I intend to screw my pod together with stainless steel screws put into tapped holes. I have to make one myself to get the size and shape I want.

 

[FullCircle]

Sheet of Polypropylene (Bread board style) which is soft and easy to work,
If you want good strength use Polycarbonate, same as your boat windows (but colours are a bit washy)

If you need to form it, use ABS (used in vacuum forming) sheet, good all round properties and very available.

ABS mixed with Polyamide is what is used in things like motorcycle fairings.
Also available is PC/ABS, which is a Polycarbonate with ABS, very high strength.

All of these have external grades, but are not standard, so be a bit careful.
UV in the med will degrade them over a 5 year period if they are not exterior grade.

Are you looking for an offcut? The seek out your local vacuum forming company and get an off cut from them, or possibly a local supplier like we have in Southend, EJ Alloys.

 

[srp]

I would mould one with epoxy and woven glass cloth, using a large tupperware-type cake box as a mould. There was one in an old edition of PBO that was actually just a cake box, sprayed white with stainless straps bolted on.

 

[Blueboatman]

Nylon 66 machines nicely,takes self tappers,will not crack or shatter when cutting and you can even plane it with a low angle wood plane(!).
Having used it extensively to make component links and bearings for a windvane I can testify to its uv resistance in the tropics after several years..
Starboard or Kingboard is also very good too and stable,like what you cut the bread on,as mentioned.

 

[oldsaltoz]

G'day Norman,

Having built a few pods I can assure you one from closed cell foam and glassed is both simple and very durable.

From a basic flat sided to a complex curved units complete with hood for protection and good daylight visibility.

You can also include internal lights and cable entry points via upstanding tubes to ensure no water entry.

Super strong and last a lifetime.

Avagoodweekend......