GE Silicone I
 

Has anyone used it?

There's GE Silicone I and there's also GE Silicone II. Both, if I recall correctly, say "100% silicone." But Silicone II says "do not use for aquariums" but there is no such disclaimer on the I.

Anyhow I think I've used II in the past with no ill effects, but for some baffles in a sump I just built, I used Silicone I this time.

After a few weeks it has started to discolour underneath the waterline? I.e., it's turning yellow from clear.

Not sure what to think about that .. Maybe it's just some slime that has some affinity for the silicone and not to the glass? I'll try rubbing it off to see if it becomes clear, but I think it's the silicone itself that's discolouring (oxidizing maybe??)

Sump with baffles sat dry for about a week before it got put on the tank so I don't think it's the case that the silicone didn't have enough time to gas off and/or cure...

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Has the silicon hardened at all?

I'm not sure I follow ... Hardened as in become brittle? Or as in "not gooey anymore" ?

It has the usual consistency of cured silicone ... soft but not gooey. Hmmm, don't know how to really describe that texture.

I had a batch of silicone that was either old or maybe got too cold in storage, and it never really fully cured. After a couple of days of sitting you could still smoosh your finger through it.. Is that what you mean? Anyhow it's not like that, it did fully cure.

how long did you let it cure befor you put it in use?

Steve

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What I meant was brittle I guess. Some silicone that I have used has become brittle, most likely because of the effect of the salt. As long as yours still feels like normal cured silicon I don't think the dicoloration should really be of any concern. IMO

About a week, give or take a couple of days..

Are you refering to the silicon at homedepot doors and windows if you are i wouldnt use it i was going to and then buk a neer said even though i says 100% silicon it could still contain anti fungus stuff or somthing along those lines. So this being said i called GE a few days latter and they said it does contain some sort of stuff like that i cant remember what they called it and said to use construction silicon GE1200 and one other kind for my aquarium.

Kitchen and Bath silicone has an antimildew agent and definitely should be avoided.

"Silicone II" I thought might have some agent, but I don't recall the labelling anymore. Which would explain the "not for use on aquariums" disclaimer. That's why I avoided it. I read the label several times, there is no such disclaimer on the tube on "Silicone I". Darn it, now I don't remember, I'll have to read it again.

But nonetheless would the presence or absence explain a discolouration? :confused: I'm kind of thinking that could be a different issue.

Hey where is a good place to find the GE1200 anyhow? I have trouble finding that stuff. If I could have found that at HD or Rona or where-ever I was that day when I was looking I would have used that instead, but there was none that I saw.

Just did a search on RC and found out other people who use clear silicone have the yellowing. In their case they used Silicone II though, so I guess it doesn't matter about the difference between 1 & 2, if it's clear, you'll notice the colour. I've always used black in the past so maybe it's just a case of never noticing that there was discolouration.

Odd though, that the clear silicone holding the tanks together don't discolor. Different silicone? Or different curing method (more time??) ? :confused:

Anyhow would still like to know where's a good place to get the 1200 or the 128rlt or whatever it's called ... so I know for next time. Thanks!

Most tanks are put together with Ge1200 Tony.

I have seen it at Able Orings I believe.