Sylgard or TPE

[yopappamon]

I know we've discussed using a thinned silicone to encapsulate a diy solar panel.

But if your choices were potting with Sylgard or using a sheet of TPE and a heat gun, which would be better? I don't have a vacuum chamber or large oven, but can you get a good encapsulation with TPE and a heat gun?

I've spent the money on decent cells, a solar panel frame, I want the panels to last. I kind of wish now I had just bought a factory built panel, but too late for that.

[Harold in CR]

From what I read and saw on Youtube videos, you need a very good heat gun. It will take a long time to shrink wrap the cells with the membrane system. That's why I posted about the Silicone. I am about to have a bunch of stuff shipped down, and, Silicone GE II is part of that shipment.

If you do the membrane, and I do the Silicone, we have something to compare. I would have to cut some membrane off one side, because I am going with 5 Wide X 7 Long, 6" cells. That would create a weird size for the available membrane, and waste money for me.

Still not certain what I will do for the backside. Down here, the Sun travels directly over the house, so, the angle of attack will be more direct that other areas of the world. I also want to do a tracker, just following the daily track of the Sun. If the Silicone is thin enough, I may just try pressing on Glass MAT, gently, to embed it.

[yopappamon]

Harold, have you done a trial run with the silicone yet?

The TPE would be cheaper than Sygard by almost half. I can get 1x10meter sheet for a little over $100. That would do all 4 of my panels. Sylgard seems to be about $50 per jar.

Thinned silicone would be really cheap but I'm a little concerned about it's life span, how well it would hold the cells to the glass, and it's affect on efficiency over time.

[Harold in CR]

No, haven't used it, yet. Only problem I have with the membrane, other than long time to work it down, is, if you mess up, somewhere down the line, before the panel is completely down, you will probably break cells trying to correct the error.

The Silicone will give you time to inspect all the wiring, connections, and position of the cells, before it starts to set up. It will take several days to get semi-cured, so, I feel confident it will be OK.

Also, not that I'm wealthy, but, if the panel has a shorter than expected life, I think that cells and or panels will be more affordable, as the years go by.

I have tried to contact the poster from the thread I linked to, to get an update. Seems to have vanished into this air ?? Don't know if that is good or not

Can't remember if I asked you before, but, have you watched videos of the film being applied ?? Sure would recommend practicing first, before doing a panel for sure. That Sylgard is just too expensive for me.

Daylight down here, is, from 5AM or so to 6 PM or so, year round, so, I have plenty of time to work on stuff, where I can't do much outside. I figure to have around $78.00 per panel, if all goes well.

How soon will you get started on your panels ?? Please post success or failure. I will do the same. Good Luck.

[yopappamon]

No, haven't used it, yet. Only problem I have with the membrane, other than long time to work it down, is, if you mess up, somewhere down the line, before the panel is completely down, you will probably break cells trying to correct the error.

That's a good point. Maybe I should do one of each. I have cells for 3 panels and frames for 4.

I have to get the glass, then I can start. I'll probably make a fixture for spacing the cells when soldering. Like a piece of stiff board and glue down some 1/4" tile spacers then start tabbing.

Do you think the silicone will adhere to the glass well and not delaminate over time?
Should I be worried about air under the cell? Seems if it is encapsulated in a dry environment it shouldn't have condensation in the air pocket.
How thick are you going to make the silicone layer? The Sylgard must go on pretty thin since you use one jar per panel.

I have seen some of the videos of people heating down TPE.

I'll keep you posted and take picture.

[Harold in CR]

The videos of using Sylgard, showed the stuff about like warm Honey. Pour it in the grooves all around the areas between the cells. I'm going to "try" to put the Silicone all over the cells and glass, them mash the lightweight glass Matte into the Silicone. Probably use a large square sponge, to get pressure but not enough to break the cells. When doing resin and glass, use a dry paint brush to start, and kinda "peck-peck-peck" at the glass, to push it into the work and work out air bubbles ??? Haven't thought much about the technique, until this evening. Too many other brush fires to stomp out, around here.

Them are SOME FRAGILE critters. Hope to get a little to creep under the edges of the cells, to form a somewhat seal larger than the openings around the edges between the cells. Might even try a heat gun-hair dryer, to see if I can warm the air between the cells and glass, so, "maybe" it won't sweat and condense.

Might even spread it out thin and lay the cells right in it. It does dry clear, after all ???

[amberwolf]

To prevent getting moisture encapsulated in there with the cells, you could setup a small room and run a window air conditioner very cold for a few hours, perhaps a day, on very low fan speed so that moisture will collect on it's inner coils, then when it stops each time it reaches the cold air teperature it's set for, the fain should shut of so that the condensation will drain and thus dry out the air in teh room considerably.

Once dry, the room can be allowed to warm again, or even be heated purposefully, as long as it is reasonably well-sealed against outside air entering. If possible, an "airlock" or entry room that has a double door, to help prevent inrush of outside moist air, will be even better.


Building those panels in such a lowered-moisture room should help with future moisture-related problems.

[Harold in CR]

Good idea, AW, or is that LIW ???

Only problem I have with that, is, I have NO A/C. I DO however, have a dehumidifier. We have a small bathroom, and, when the clothes don't dry quickly enough, I make up racks over the shower area, and plug in that dehumidifier. After about 4 hours, the room is very warm, and, the clothes really get to drying quickly.

I just might try that idea of yours, in reverse. Don't see why it won't dry out things first, then, pour in the Silicone, on warm glass and cells ??? See anything wrong with this idea ???

[amberwolf]

Well, if the dehumidifier doesnt' actually collect the moisture and put it somewhere else than the air, then it won't help. If it is like some of the ones I've seen here that heat the air, all it is doing is heating the air beyond the dew point so it doesn't collect on walls and mirrors, etc., causing the water to stay in vapor form. That won't help in your case, as the vapor would still be just as present in the air trapped within various layers of what you're building. If tiny amounts of moisture could present a problem over many years, then you'd want to do something to try to actually remove the moisture.

I'm sure there are other ways to do it, but the A/C was my first easy thought.

Those silica dessicants in the little packs that come in so many products from medications to electronics would also work, but will take probably a lot of time to work (unless you first grind them up into powders for more surface area, and spread them out on trays all over).

Keep in mind also that when you come in, you'll bring moisture with you and your breath will have it in there, too, with every exhalation. If you wear one of those filter cartridge masks, it may help absorb some of it depending on how it's exhaust is designed (you might have to add an exhaust absorber using those dessicants to make it effective).

Whatever way you do it, if you do it, just make sure to test the method by monitoring humidity in a few places in the room at different heights and distances from the walls and whatnot, so you at least know it is doing something and if it is worth the trouble (could be a lot of trouble).

[Harold in CR]

The dehumidifier collects the water, and I run the hose right out of the collector, directly into the drain pipe. It will dry a wet bath towel in under 2 hours, as it dries all the other stuff along with it. I do believe it will help control condensation, especially with everything being encapsulated.

[yopappamon]

Here's an interesting product. Used for potting fake flowers. Dries water clear, minimal shrinkage. Around $28 per 32 oz.
Don't know if it's acidic but is UV resistant.

http://www.smooth-on.com/tb/files/Encapso_K_TB.pdf

[yopappamon]

Looking into it more. To use the laminator sheets you make a 5 layer sandwich... Glass, EVA, cell, EVA, TPE

End up with $60-80 materials cost per panel, plus an hour of heat gun time. Without a vacuum laminator you will probably have bubbles. Makes the cost of Sylgard look attractive.

Maybe I'll try a test run with silicone.

[Harold in CR]

With Silicone, I have read, thin it with Mineral Spirits, and add a few DROPS of Glycerin, available at Pharmacies, even down here.

[yopappamon]

What is the glycerin for?

[Harold in CR]

I believe it's for delaying the setting time. In the thread where I describe the Silicone idea, there is mention of the Glycerin and why it's used. Maybe search for Suppositories. That's what the guy I got the info from, uses. He dissolves it.

YUP, that search works.

[yopappamon]

I'll have to go back an read that thread again.

Doesn't the thinned silicone shrink on drying?

I'm thinking now about laying down a very small - heavily thinned layer of silcone on the glass, laying in the cells and making sure there are no bubbles, then overlaying everything with lighter thinned layer of silcone.

My cells are slightly warped and the first layer should hold them flat against the glass and keep air out. Probably will need to weight them down flat until it dries.

[Harold in CR]

Never read anything about Silicone shrinking.

Your latest plan is exactly what I have decided to do. I will lay lightweight Fibreglass Matte on the backside, mashed into the Silicone smeared all over the backside of the cells.

Wish I had easy access to Formica sheets. I would take a sheet, cut to just a tad under size to fit the frame, and s,ear paste wax on the Formica. Use that to lay on top of the glass matte and weight it with plastic bags of sand. It will peel up easily, without pulling the Silicone loose. Use on all the panels you ever build.

I really think we have a winner planned out. GOOD LUCK Wish my Son would get off his ass and ship my stuff down, ASAP.

In all fairness, he is VERY busy in the crappy economy, and works 14-16 hour days, 7 days a week.

I'm gonna rattle his cage, tonight.

[yopappamon]

I picked up the Glycerin today at lunch. $5.99 at the Rite Aide. Liquid suppositories. nice. We'll probably look like quite the perverts with those suppositories, tubes of silicone, and caulk gun!

Might try to run over the the big orange building and pick up the silicone and mineral spirits. get a test going soon.

I don't know if I will put a backing on mine. Maybe a layer of white silicone or blue if I can find it. or maybe a thin sheet of plastic board from the local crafts store.

I'm curious how well this will adhere to the glass. Will probably want to pour the different layers while the previous layer is still wet so they will bond well.

There must be some shrinkage when the mineral spirits evaperate. Probably only thickness changes though.

[yopappamon]

I don't remember, did anyone every talk about using Liquid Nails Clear Seal?

http://www.duspec.com/DuSpec2/product/ProductDocumentSearchController.htm?documentFormat=pdf&systemSetId=70&productCode=CS-144&documentType=datasheet

Someone tried it on this forum:

http://www.solarpaneltalk.com/showthread.php?1986-Possible-encapsulation-material/page3&highlight=encapsulation

[Harold in CR]

The link to that other forum was excellent. Thanks. Most of those guys are in the UK, so, I'm sticking with GE II Silicone.

[yopappamon]

Sounds like we need to be really careful about trapped air bubbles. Almost makes me want to go the Eva/tpe route.

[Harold in CR]

That's why I am spreading a thin layer all over the glass, and mashing the cells into it, with a layer of plywood or something, so I can put sand bags on it. Very slow, careful mixing, will help to NOT create many air bubbles.

I do have a small vacuum pump, and, might try to find a way to pull a vacuum on the mixing container, before spreading the mix. It is amazing how much foamy air can be drawn out of a mixed volume of liquid.

[dnmun]

if you cover your PV with this organic film then you will lose some efficiency and overall output will be reduced. also if the material is in contact with the PV itself, it may react chemically with the aluminum traces that carry the current and cause corrosion or delamination of the traces from the silicon surface. most panels have a glass cover, but you guys are making panels without it?

[Harold in CR]

Nope, we are using Glass or Lexan. The GE II Silicone has no bad chemical reaction. It won't corrode or eat into anything. Just have to be VERY careful when experimenting.

I have no problem with a slight under-performance. Just build 1 more panel or more