Plexiglass UV resistance

[woodypynes]

Thank you for the advice, Mike! I'm about to go outside and begin the installation. We're so excited! We really could have used this setup during/after Hurricane Irene last summer (we live in NC).
Thanks again, Mike.

[Bratan]

Started making panels back in '08 for use in the tropics where it rains a lot. Here is the correct procedure for plexiglass after 3 years of tinkering.

1. We use 1/16" aluminum sheet for the back, framed by 3/4 x 1/4" aluminum bar. We use U/V resistant .093" thick plexiglass. We do not enclose with aluminum channel (c-bar) and will explain why below.
2. After attaching to the panel, you must encapsulate cells with Sylgard, Corning, etc, applying a good layer of liquid encapsulant, using a brush. One batch of encapsulant is good for every two panels that are 36" x 30". (36 3x6 cells)
3. Must glue plastic, transparent "necklace beads" in the middle of panel, in between the strings of cells, so that plexiglass does not touch the cells upon contraction.
4. Everything is held in place with stainless steel screws (#10).
5. When attaching plexiglass to the panel, only apply silicone GE-II to the top. Leave sides and bottom attached only by the screws/nuts/washers. These are the areas that cannot be totally sealed.
6. Channeling will only destroy panel. It is impossible to get a 100% waterproof seal here, so panel needs to "breath". When we used channeling, the panels developed moisture/condensation and when daytime brought the sun at its hottest, water became hot vapor and the plexiglass literally exploded outward, became brittle and did not last weeks.
7. After testing for many weeks and months, panels are now totally moisture free and working at its highest rating. Whenever it rains or condensation forms, it quickly dissipates as soon as the sun starts shining.

I'm very interested in this method as I'm also trying to use plexiglass. In #2 you encapsulated cells to the aluminum backside?
In #3 how exactly did you make "necklace beads"? I'm not sure I understand that part Did you add some drops of Sylgard to the plexiglass and let it dry and then put panels on top of it? Is plexiglass not attached to cells in any direct way (i.e. you can remove it later)?

[natel]

video?

I'm interested too. I'd love to see a video of this whole process if you ever get around to making on someday.

I'm very interested in this method as I'm also trying to use plexiglass. In #2 you encapsulated cells to the aluminum backside?
In #3 how exactly did you make "necklace beads"? I'm not sure I understand that part Did you add some drops of Sylgard to the plexiglass and let it dry and then put panels on top of it? Is plexiglass not attached to cells in any direct way (i.e. you can remove it later)?

[Bratan]

I'm interested too. I'd love to see a video of this whole process if you ever get around to making on someday.

That seems unlikely looks like OP hasn't been back for a long time (only 2 posts). Anyway I'm trying to develop my own method of "floating encapsulation". It involves wax paper and liquid latex I will let you know how it goes...

[sermormo]

I planning to built my first one and I found all this info very helpfull. Thanks

[Gimpytr]

Plexiglass and Al - going to give it a try.

The necklace beads I'm going to purchase from Micheles and imbed them into the encapsulate. I let you know how it goes . By the way I'm new to this.

[Sunny Solar]

And what are the beads made of? and what you hopeful that they will do? If plastic of any type they wont last long out in the weather.

[inetdog]

And what are the beads made of? and what you hopeful that they will do? If plastic of any type they wont last long out in the weather.

Probably act as a spacer between the cells and the covering during assembly?

[Gimpytr]

And what are the beads made of? and what you hopeful that they will do? If plastic of any type they wont last long out in the weather.

How about spruce wood as the spacers. Any other suggestions?

[inetdog]

How about spruce wood as the spacers. Any other suggestions?

Wood of any kind inside the panel space will outgas volatile organic compounds when heated.

[Gimpytr]

Wood of any kind inside the panel space will outgas volatile organic compounds when heated.

Marbles?

[Sunny Solar]

Why anything?? Commercial manufacturers dont out anything there. I cant see what possible advantages it can have??

[piper34]

dsf

plexi glass and arcrylic is the same?

[russ]

plexi glass and arcrylic is the same?

Two totally different materials

[Sunny Solar]

PLEXI GLASS ,ACRILIC Seem to me to be the same,but equally unsuitable for solar panels.

Poly(methyl methacrylate) (PMMA) is a transparent thermoplastic, often used as a lightweight or shatter-resistant alternative to glass. It is sometimes called acrylic glass. Chemically, it is the synthetic polymer of methyl methacrylate. The material was developed in 1928 in various laboratories, and was first brought to market in 1933 by the Rohm and Haas Company, under the trademark Plexiglas.[4] It has since been sold under many different names, including Lucite and Perspex.

In 1933 the German chemist Otto Röhm patented and registered the brand name PLEXIGLAS