Bummer.

[pyrocasto]

When out to the barn today and noticed this:

I guess either I should sit out there with a gun, and wait for a kid with a rock, or switch to tempered glass. I'm not sure which one it was, but I have heard of regular glass breaking from the heat. I have another piece though, so I'm thinking of filling with oil and trying again.

Darn,

[drdongle]

I would bet it's not a kid with a rock, that looks like a stress fracture, a rock would leave point of impact damage.

[TomW]

Chris;

I tend to agree with Dr. D that does not look like impact damage at all.

First guess is thermal expansion stressed the glass / frame interface and the frame won..

Cheers.

TomW

[DanG]

Looks like a late night visit from Woodwarp N. Glasskiller.

Hope you get panel indoors soonest & can salvage some of that huge glass sheet!

Metal frame w/ welded corners & cross braces, slotted bolt mounting to allow for planar expansion-contraction are on my 'must have' list for sure now!

Thanks for posting the unseemly along with the beautiful !!

[pyrocasto]

I agree as well, I dont think it was a rock. But I didnt know for sure, since there were spots along the crack that were chipped up(almost cut myself on a tiny chip).

[Jeff7]

Another vote for thermal damage. I remember that someone else reported trying regular glass, and that it broke loudly after only like an hour. Those things can get damn hot in the sun. Bare cells in room temperature air, in the sunlight, got up to around 60C (140F). Now seal them up so they can't dissipate that heat as well. They'll get the air inside that container cooking in no time. I heated my prototype to about 89C (192.2F) to simulate cooking in the summer sun. It had flexible polycarbonate on it, and it was bulging out quite a bit. Glass won't handle that sort of thing very well.

[ghurd]

I would say a bad mount. Not exactally straight or level or something.

Left and right ends of the break are higher (lower?) than the center.

Maybe the right lower corner is lower than level / straight /even.

Almost looks like it in the photo of the mount too.

Like the lower left raised up?

Kind of twisted looking.

I like steel or Al brackets.

Guessing

G-

[sandovalch]

Bad luck! Perhaps you could cut the glass into smaller pieces and assemble it with some divisions?!

I use smaller pieces of standard glass 28x32" and have had no problems so far in the last 7 months, and I can tell the glass gets very hot. I use silicon caulk so it allows for expansion contraction of the whole structure.

Ch.S.

[pyrocasto]

Well, I just wish it wouldnt have waited a couple months before breaking. And I doubt the mount is crooked, because the top 2 bars sticking out is one pipe, no connections to twist or mess up. Same as the bottem.

I may have, however, put too much stress on the glass when I put the metal around it. Not letting it expand good enough when it got hot.  Who knows, I'll try it again since I have the glass anyway.

[ghurd]

Does it still work like it is?

It looks great, except for the crack.

G-

[wgatenson04]

may be a stupid question, is it windy at all where you live???

Or, metals and glass not expanding at the same rate? thermal then I guess

[pyrocasto]

It does, but not good. It gets all fogged up now, so I'm replacing the glass before I ruin the cells.

[pyrocasto]

Actually it has been windy lately, but I dont think that's it. We have had snow and 60 degrees next day lately.

[BT Humble]

I guess either I should sit out there with a gun, and wait for a kid with a rock, or switch to tempered glass. I'm not sure which one it was, but I have heard of regular glass breaking from the heat. I have another piece though, so I'm thinking of filling with oil and trying again.

While I'm not going to argue with a man holding a gun (it's loaded with rocksalt, right?), that's not caused by a rock.  I've dealt with a few solar hot water collectors, and they tend to crack like that if you twist the frame too much while carrying them around.  Was your frame made from wood or metal?

BTH

[BT Humble]

I agree as well, I dont think it was a rock. But I didnt know for sure, since there were spots along the crack that were chipped up(almost cut myself on a tiny chip).

As an experiment, put a piece of it along the edge of your workbench and snap it off.  If you don't scribe a line with a glasscutter first that's the type of edge you usually get (little flakes of glass, not a clean cut).

TH

[pyrocasto]

Wood frame, but it's bolted down in 4 places so it's pretty straight. I could use a little thicker caulking/silicone though, to help keep everything level.