Curing large quantity of silicone ... takes longer?

[Delphinus]

Has anyone tried to sandwich a piece of glass onto another with a film of silicone between? How long did it take to cure?

I imagine it's fair to assume it will take longer than say a bead of silicone along the edge or a corner. But if, say, 12 hours later and the silicone is still quite wet to the touch, is this normal?

Does silicone have a shelf live? Or if it gets cold in storage or something can it become ineffective (i.e., unable to cure)?

[Buccaneer]

Should not take too long Tony ... I usually wait 48 hrs before I attempt to test any silicone joints.

Not sure on the cold thing but temp range should be on the tube or in the specs

[Delphinus]

Yeah, I was going to wait 24-48 hours (or more, even) before putting a load on it, but in the past when I've siliconed in baffles or replaced a panel, the silicone would "film over" within a few minutes. This time, nothing, so that's got me a bit panicked: if after 48 hours and this stuff hasn't dried, and THAT'S when I start to go to "plan B" then I have an even bigger headache on my hands than I do right now.

Actually I'm not really sumpless at the moment, for the moment I'm just running the drain into the next baffle over, and so the end part is just empty. But at the moment I don't have the reactor or the skimmer online, it's just for the sake of the heater.

Maybe I should admit defeat now and start working on finding or building a new sump (and getting new silicone). Cut my losses earlier this way perhaps.

Sigh ... All I needed was one hose attached to one hose barb. :frown: Stupid 1/4" glass ... if I had a nickle for everytime I've broken a 1/4" panel ... I could afford to splurge and get ..... 3/8" glass ... :neutral:

[muck]

I tried to use "old" silicone on a project once. The same thing happened it only half cured. It was still wet to the touch after a day or so. I don't think the tube ever got cold or froze cause it was in the basement but im not 100% sure of that. (could have been in the garage over winter) I ended up removing all the silicone, buying a new tube and having to redo it all. The new stuff was tack free in a few hours for sure.

For me its worth the 5 dollars for a new tube when I start a new project. I will keep partial tubes but only for a short period of time now. Its not worth the headache IMO. Probably not what you wanted to hear.

[Delphinus]

Uh, yeah actually in a weird way it does tell me what I want to hear. I'd rather find out "now" than in two days (or whatever) that "it didn't work".

Hmmmm. Off to find a new sump.

PS. Who makes tanks out of 1/4" glass anyhow? Don't they know that there are people like me out there trying to use them ?! :lol:

(... sigh ...)

[AJ_77]

...

[Delphinus]

Snuck home at lunch to check on my patch job ....

Nope, silicone not even remotely dry. Like toothpaste after 16 hours. I guess silicone does have a shelf life or the temperature encountered during storage can render it "broken." (Tube I used was stored in the garage :redface: )

Am still going to try to salvage this sump. Just need to get some new silicone.

Edit - err hmmm. I have a new question but I should probably start a new thread for it.

[Canadian Man]

One trick to cure silicone faster is spray is with a mister a few times a day.

It works wonders!

May not help old silicone syndrome though :confused: