Looking at plastics like UHMW and delrin... wondering how important is "UV stabilization" for outdoor use? How long does it take for ultraviolet light to damage the plastic? Months?
If it really matters, is black Delrin most likely to be the UV stabilized type? Many of them say the color is black but they don't specify UV stabilization or the specific Delrin part number/type.
Thanks.
Polyethylene tubing will positively crumble after a year or two in sunlight. I had an injection line on my pool that would leak under pressure after 3 or 4 months.
Consider wrapping with aluminum duct tape.
Very.
If you are lucky.
Lew
Yes, months but varies with your climate and sun exposure. If it is not specified with UV inhibitors, don't count on it being there.
If a grade is not specified chances are it can vary or be mixed. Black molded parts are the best for getting rig of rejected parts by grinding them and blending in the virgin material.
For the vast majority of projects, I would guess No.
My problem isn't just a matter of cost, I'm going to start with only about 1 foot of Delrin rod. The problem is trying to figure out what is UV stabilized and what isn't. I asked McMaster-Carr and they said they don't have any more information than what is on their website, the specifications listed with the product. Other online outlets give about the same information.
My project is experimental and maybe the exposure to sunlight will be limited enough. It's a first design, and that usually sucks anyway, so I should probably back off on the UV concern for the moment. If it works, I'll take the advice and spend more on the subsequent design, ordering from a more specialized store like the ones that require minimum line item and total order amounts. But, to begin with, I'd like to experiment with a short rod of several different Delrin/Acetal types. The project can actually use more than one type at a time.
Thanks.
DuPont's UV-stabilized Delrin (there are several grades) is a popular material for sailboat sheaves, and has been for decades. I had some of them on my keelboat that was in the water 6 months out of the year, with the sheaves constantly exposed to the sun, and I had no problem with them over a period of 5 years or so.
It's a common material. You shouldn't have any trouble finding it.
-- Ed Huntress
Available here...
I think you'll find balck Delrin will last several years under moderate sunlight exposure. I used to build hardware for high-end custom sailboats. We made custom fitted anchor rollers with a choice of bronze bushed stainless or Delrin sheave. A Delrin sheave was considerably less expensive, and I don't recall ever receiving a complaint or a request for a replacement.
Here's the sort of thing I'm talking about, from the present incarnation of my business. The anchor is resting on the sheave.
I bought some of that black Delrin from McMaster-Carr and made some masthead sheaves for my little sailboat out of it. I also made two spares just in case. It only took 1 hr to make them. Haven't tried them yet, the ice just melted. I'll let you know if they fail this year.
I bought 9 feet total of small diameter Delrin and acetal copolymer, much more than enough. If it's not slippery or durable enough, I might try Delrin AF later. All of the stuff in my most recent order was either rod, flat bar, or tube. I was pleasantly surprised they were able to ship the stuff UPS ground, including two 8 foot long aluminum tubes, for only eight dollars. Shopping online is great when you need to know technical information, even though they couldn't tell me whether it's UV stabilized. The local Borg wouldn't even know what type of aluminum or steel their rod/bar/tube is made of. All the online merchant has to do is include the technical information with the product description.
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