Using recycled plastics 2

[HarryDen]

Hi,
I want to made some surfboard fins out of recycled material. They'd be cut by CNC.

However, I'm having trouble finding a recycled plastic. 30% glass filled nylon is normal used but i cant find any recycled.
Does anyone know
A) Where i'd source some
B) An alternate plastic which is Just as strong, resistant to salt water and UV, available recycled etc. basicly as good as glass filled nylon.


Thanks for the help

 

[btrueblood]

Recycled plastic with fiber content will be tough to find as it doesn't recycle easily.

HDPE recycled into sheets and boards is common, at least in the US:

http://www.ecobusinesslinks.com/recycled_plastic.htm

HDPE can be pretty tough stuff, maybe not as high a tensile as GF nylon, but it can take a beating without fracturing. Pretty much inert to seawater, though you'd want some UV stabilizers. I think the products being made for outdoor use (decking/siding) would have those added.

 

[MikeHalloran]

The local big box lumberyards carry brown-ish decking allegedly made from recycled plastics. It's nowhere near as stiff as GF nylon, or even softwood, and appears to have a lot of particulate (real short fiber, or sawdust, or dirt) material in it, so you'd never get a nice finish.

A while ago, there was an outfit making dimensional pseudo-lumber out of coarsely chopped partially melted postconsumer PE. It was even more flexible than the decking, contained major flaws and occasional identifiable inclusions of ordinary garbage, and looked greyish at a distance, but up close retained a melange of bright colors that clashed with each other and themselves. One municipality installed some outdoor furniture made of it, but there were allegations of impropriety because the municipal leader and the manufacturer of the material happened to be married to each other. I haven't seen the stuff recently.




Mike Halloran
Pembroke Pines, FL, USA

 

[patprimmer]

I have been involved in the development of injection moulded surf board fins since 1977 when they where polycarbonate transparent tint colours.

They progressed fron clear PC to GF PC to 35% GF nylon to 45 to 50% GF nylon and even PPS to meet the market demand for fashion colours and performance.

Flex mod along with excellent fatigue and reasonable impact is critical. They seldom last long enough for UV to become a real problem.

There are a few tricks to moulding them without flow marks. I am not at liberty to disclose some of those tricks as I worked them out years ago with a customer who still insists I stay at his home whenever I visit Brisbane due to my involvement in the development process.

I have been intermittently involved with both The Australian Fin Company products. They also moulded for other companies based in Sydney and Byron Bay. I was also involved with Speed Fin Systems through another moulder whom I was already closely aligned with via earlier projects particularly car roof rack systems and "floating" yacht winch handles. I needed to be very careful to provide equal service without betraying confidential information as I was commercially and personally close to both.

With my experience with world leaders in this market, I would not entertain the prospect of repro in this job for one second. It is a difficult moulding and a demanding application.



Regards
Pat
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[731226]

I think PC GF20% might be solutions. We are mixing the virgin and recycle resin(50% and 50%)

 

[patprimmer]

Prime 20% GF PC failed in this application years ago due to lack of fatigue resistance and flex mod. I very much doubt repro PC will suffice, especially if the repro is bottle grade or CD grade.



Regards
Pat
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[HDS]

GF nylon will probably not be post consumer recycled but in process scrap recovery called regrind.

In the US most folks do not advertise the amount of regrind in their products. You have to ask for it. If you buy enough you can tell them how much you want.

The availability will fluctuate if they buy the material on the open market instead of from a regular source.

 

[patprimmer]

I would never use outside sourced regrind in a surf board fin. I would only use the fresh scrap from the runners and sprues and never added at more than about 10% as regrinding damages the fibre and re-drying wet material damages the resin especially after the thermal history from the first moulding process.

Regards
Pat
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[dgallup]

BASF Nypel 6030G HS BK is a 30% glass reinforced heat stabilized, pigmented black, injection molding compound based on recycled nylon 6 feedstocks. It is available in natural and black.