Epoxy for encapsulating cells (great DIY thread with photos!)

[Eric]

I like the idea of seeing one's work and to be able to verify the perimeter seal. Is that Dap product ridged or soft and flexible?

It's not rigid but it's not ultra soft. It's about what you would hope for, let's call it a firm cushion and a quality seal. It says that it is designed it to protect in exterior applications where you want the beauty of the material to show through.
In my case I just want the sunlight to get through to those pretty little blue electric wafers and it seems to do that perfectly well.

Mike, yeah, I think I'll try the silica method (no vacuum) on my next panel.

[BilljustBill]

I'm just starting to work with DAP 3.0 crystal clear and I'm really liking it so far. It really is as clear as I have seen out there and it has fantastic adhesion/flexibility. It's kind of expensive @ $7.50 (Home Depot) for a standard caulk tube but I used only two to three tubes total.

I've seen and used a crystal clear sealant called "Lex-Cell" that cost about the same as what you've used. I put a 1/4" thick window in my workshop's dust collection 55-gallon barrels. Two 3hp vacuum blowers are very strong. It took the LexCell to withstand any air leak because, like the Plexiglass, it is crystal clear and dries a bit tough and nothing like the soft flexibility of silicone.

I like the idea of seeing one's work and to be able to verify the perimeter seal. Is that Dap product ridged or soft and flexible?

[Mike90250]

..... I was also considering adding silica desiccant inside the space between the cells and back sheet in lieu of vacuuming at all.
Thoughts?

I'd vote for the desiccant, and skip the cell busting vacuum.

[Eric]

I'm just starting to work with DAP 3.0 crystal clear and I'm really liking it so far. It really is as clear as I have seen out there and it has fantastic adhesion/flexibility. It's kind of expensive @ $7.50 (Home Depot) for a standard caulk tube but I used only two to three tubes total.

Like everyone else, I though Sylgard is a great product but there are a lot of things I do not like about it. #1 price. #2 isolated bubbles are almost a guarantee in any DIY application #3 Cure time is far too long.

I'm considering using this technique. I've already tried it once and so far I've been impressed.
Layer order
1/4 Glass
cells fully assembled
DAP crystal clear dabbed all around about every 1.5"-2.0" with no continuous beads.
Wait 24 hours.
Apply continuous bead of standard all weather silicone around perimeter of assembly.
Apply back sheet of your choice (clear allows you to see what's happening in there. on top ensuring that there are no gaps in perimeter bead.
Apply weight allow to cure for 24 hours.
drill small hole in back sheet in a known safe location
Gently Vacuum air out of space and seal immediately with adhesive foil tape. I used a Reynolds Food vacuum (used with their bags)
Some Cells may crack during vacuum process but I found that more crystal clear dabs helps to prevents this.
In theory you will have a fairly decent partially vacuum sealed assembly at about 2/3 the cost of Sylgard and without much bubble worry.

This is a work in progress but I will try to update people on the success/failure of it.
I was also considering adding silica desiccant inside the space between the cells and back sheet in lieu of vacuuming at all.
Thoughts?

[lesticx]

What about using something like sikaflex?

http://www.sikaindustry.com/ipd-ma-products

It's not expensive, granted it's not see-through either. But I think I could just glue the cells with sikaflex to a hard plastic sheet from the bottom side, then put a plexiglas etc. on the front, and glue that in place with sikaflex.

Point is: this kind of substance is in essence elastic, it's meant to be used in boats etc.

What do you think of this idea?

[DeltaFox 25]

that sounds real good . any pictures??

[bladerunner]

A Paint brush works fine, used cheap disposable ones, one for each batch.
Another word of caution, stir in the catalyst VERY well, one of my batches did not cure all the way, and I think not stirring enough was the reason. Stirring for about 10-15 minutes seems to work well for me. letting sit afterwards for about 15 minutes let all the bubbles rise to the top and pop, so you have less to deal with.
Because it is cured by the catalyst and not the air, you can put plastic on the back, and the sylgard should still cure fine.(mine did)
here is an outline of what I did:
1)Solder together all cells used in panel, instructions can be found lots of places on web MAKE SURE YOUR SOLDER JOINTS ON THE FACE OF THE CELLS IS SMOOTH AND FLAT. If it is not, you will have voids in the sylgard caused by the solder holding themselves off the glass.I kept them on a piece of cardboard, to more easily move them
2)make dam around area cells will occupy ( I used strips of plexyglass, silicone has worked for some people.
3)mix sylgard(10-15 min), clean glass w/alcohol, paint layer of sylgard on glass, If it was "grabby" I added a bit more, tried to get it pretty even.
4)slid the cell assembly (face down) onto the sylgard covered glass from the cardboard.
5)painted back of cells w/sylgard, this seemed to press them into the face sylgard pretty well, but then I had bubbles from the edges of the cells curling.
6)stretched cling wrap across the back, put weights on corners of cells to hold them down. (one some of my panels, I put a thicker plastic, and had to use heavier weights to hold it down as well, not sure which one works better. The sylgard supports the cells pretty uniformly, so you can put quite a lot of weight on the cell without cracking it. coffee cups and glasses seem to work ok sockets,large nuts, maybe flat rocks?

[DeltaFox 25]

Maybe you could use a paint brush to spread the slygard.

[mrnewbie]

Artificer...

"I've never done this before, so I have a few questions. People mention 6x6 cells curling. How much do they typically curl?

If when you solder the tabbing wire down..the tabbing wire curls up..the cell will curl up as well..Your goal is to make a nice flat cell..so try and keep your tabbing wire nice and straight...

So If your soldering the BACK side..and it curls up or down..then you would want to make sure the bow..in the tabbing wire your soldering is the just a little in the opposite direction to help..straighten out the finished cell..
I dunno kinda hard to explain..after making a few you will figure it out.
A little bow in the cell will not hurt anything, but it will take more sylgard to fill in the gap..and sylgard cost $.

"Can you flatten them by pressing down, or do they break?"

You cant really bend them back into shape.they spring back..outa shape.the tabbing wire solder flexes them back if it was not a perfect solder job.

Well when you sylgard your cell you can try something like a little weight on it (Spark plug type socket, shot glass, ect), but if it gets slygarded down..its real hard to get off without breaking cell ..as mentioned before someone else said they put a little piece of wax paper under weight, then just leave the wax paper..making sure your weight does not get sylgarded down..

Why do you need to spread the sylgard around..if you put your glass on a flat surface..and poor the sylgard on, it flows around pretty good..it will take it 10 min..but it will level itself

If you wanna scooch it around...think more like rubber ..like old windshield wiper blade...or even a flat piece of cardboard would work just fine. No need to go buy anything

Note..the Sylgard does not dry in 2-3hrs...takes 2-3 days..at least if you do it in the house like I have..also..it has no bad smell..

[DeltaFox 25]

From My experence that I have had with Slygard it is a little thicker the something that just runs. I would say the Slygard that I used was kind of like STP maybe a little thicker.

[artificer]

Michael a Trowel?
I don't think a trowel is gonna work..sylgard is almost like water..very thin..

Instead of trowel, think screed like they use in concrete. Something held a precise distance from the glass, and you draw it down the surface. I should end up with a fairly uniform thin coating of Sylgard on the glass. You don't want much. Lay down the cells, and then cover with the remaining Sylgard. Let cure, and possibly coat the back with something else.

I've never done this before, so I have a few questions. People mention 6x6 cells curling. How much do they typically curl? Can you flatten them by pressing down, or do they break? Which direction do they curl? along the tabbing wire or around it, or all over?

My Sylgard from Essex just arrived. 2 units only, but I ordered online without talking to anyone. Since I didn't see any information on minimum orders on the website, I would be interested to see if someone could do a one kit order online.

Michael

[DeltaFox 25]

Thank you , i have several panels ( I call it the old way) with just one pore thats over the back and hope it would go around the frount , untill I see a guy that did it the way i said. I plan to use more slygard this way but I'll have a better panel for it.

Keep in touch and let me know how everything is going and don't forget take pictures.

[mrnewbie]

I don't understand why your sorry..

I was lookin for a better way to do it and you replied..Thank you

I'm not trying to convice you to do it a different way.
In fact I think your way (The Delta puddle method) is better than simply pooring around the cells like I had done before..not happy with results


".. put all the cell togeather , solder all , lay them on something else like card board or somthing else. " Yes I understand

I plan to do this on a second piece of panel glass like mentioned above..its already the right size.

[DeltaFox 25]

I'm sorryn but I have to stick with the way I do it. i have to many panels that have airbubles in it up till now.can you get a 1/4 " piece of plywook . Mark off the area that the cells need to fit in.
sloder your cells , put them on the plywood. once you get the slygard on the glass . all you have to do is slide ( probly with help) the cells onto the slygard thta is on the glass.
then put the other slygard on top of that.
.. put all the cell togeather , sodler all , lay them on something else like card board or somthing else. Make sure they will fit in the space you are going to put them in. Now put sylgard on the glass , now get your fully assambled cells and put them ontop of slygard that is on the glass, OK now put more slygard on top on the cells you just layed down, let it set untill dryed.

[mrnewbie]

I could just use another glass panel...

I just poored the sylgard around edges of cells..(back of) and let it flow around to the Front(blue side/glass side)...to many air bubbles left..at least I'm not happy with it.


So you have used this method, and It gets rid of most of the air bubbles correct?

I'll be doing it or something real close to your method...