Looking for a Good Outdoor Plastic.

For almost any similar question, the best place in the US to start is GE Plastics. They have application engineers, as well as a list of fabricators (usually - that's sort of a sales extra, I think).

It is my understanding that there are two basic ways of making plastic UV stable. One is to use a sacrificial additive that breaks down over time that protects the bulk plastic, the other is to mix a lot of carbon black into the resin. The first has a limited lifespan depending on which stabilizer is used and how much, and will eventually leave the plastic subject to UV damage. The other has an much much longer lifespan, but is not terribly attractive. You are pretty much limited to black for the color. Darker colored plastics with UV stabilizers will tend to last longer than lighter colored ones because the colorant itself absorbs much of the UV falling on it.

So the question you'll have to answer for yourself is how long is long enough?

I will give this some additional thought and respond soon (traveling) but I do know that polycarbonate (Lexan is one trade name as mentioned) often doesn't do well to constant exposure in the 'soup' that can exist as "spa and or pool water" - various methods (and levels) of sanitation / shock etc, incorporation etc in addition to the UV exposure -

Jim

Thanks Jim!

I await your thoughts....

Bill12780

I'm no plastic expert..but how about lexan?

The window industry face the same problem with color fading. Their answer was the laminate the vinyl with a colored plastic which would not fade as fast. It still fades in time. They also can laminate the vinyl with wood veneers that can be stained. There is all so a water based color bonding that can be done to vinyl. All so the color can be restored some what with cleaners made for boating cleaning. A vinyl boat cleaner will remove a good bit of the surface oxidation, restoring some of the color. Your WEB site listed the material as PVC. PVC plastic has a memory so the warpage is due to being poorly extruded. Extruded wall thickness may be to thin. The shape of your steel reinforcement can be change to correct some of that problem.

No guarantees, but try a search on this: TIVAR^® Ultra High Molecular Weight UV Resistant Polyethylene. It's used in agricultural applications and is highly UV resistant, corrosion resistant, and tough.

Technical Specification Table

A stabilized HDPE should work. They are making park benches and decking material from it.

The composites industry has to deal with UV degradation routinely [your average bass boat for instance]. They use TiO2 added to the gelcoat or infused with the liquid resin prior to molding. The TiO2 protects against UV pretty much indefinitely. Just make sure there is at least 15% TiO2 in the surface layer. One of my clients has a model that has been sitting in direct sunlight since 1977 with no damage.

The slats can be made of extruded isophthalic polyester with the TiO2 infused or post finished with iso gelcoat with the TiO2 in it. Either way the slats will be impervious to the UV and the chemical laced water. Isophthalic polyester is used routinely to line water treatment tanks.

Strongwell in Bristol TN makes or can make just about any profile. Hope this is helpful.

Monkeywrench

Hello everyone,

Has always lots of good information! I am still researching all this.

I failed to mention (because they failed to tell me) that we (the company I work for) that we are NOT willing to make new dies.

So this will limit me to plastics only. Although I do like the Recommendation of a Polyester with a UV additive. But as you all know a glass reinforced product will ruin the die after a awhile (at least that is what I have been told)

So keep the info coming if you have any further thoughts. I am still looking at all the variables.

Thanks for all your help! CR4 is like having the biggest engineering staff on the planet at your finger tips!

Best to all!

Bill12780

If your are concerned about the life of profile dies, you can purchase the TiO2 loaded isopolyester in sheet form of prepreg. The slats could then be cut and stamped to form. The dies would be considerably cheaper and should last indefinitely.

Instead of changing the material, how about adding a coating to the material. I do not know of a good coating to use (conformal coating for pcb's came to mind..this isn't my realm), but maybe someone else here on the boards does know of something suitable.

Sorry, the last comment was from me. Neglected to log in.

acrylics.