GE II Silcone...

[Justdrew]

Originally Posted by apexkeeper

I contacted GE directly and they said the ONLY difference between silicone 1 and 2 for windows/doors is the way it cures. 2 doesn't use acid to cure, its a "neutral cure" so its less pungent. Once fully cured both 1 and 2 are identical.

The GE I releases an acetic acid form while curing. The GE 2, with it's neutral cure, releases ammonia I believe. I used the GE I for windows and doors, and had no problems. Cured for about 2-3 days and all was good.

[Khemul]

Originally Posted by Mhay

+1 over and over again.

It's not worth it to risk it. I keep beating myself up for using the wrong kind when they make something specifically for use in aquariums.

But that's the thing. They don't. They make something that is relabeled "aquarium silicone". They don't make something specifically for use in aquariums.

[living_waters]

I used the GE silicone for my fuge months ago and it works great my fuge is the heart of my filtration but in all honesty I don't remember if I used one or two.

[gaberosenfield]

I actually used the cheapest, most awful, toxic smelling silicone I could find for my sump baffles...

Let it cure on the porch until I could no longer detect that awful acetic anhydride smell (which took WEEKS). Then I washed it out with water (because dust and leaves had settled in it in the four or five weeks it sat outside) and hooked it up to my system. No problems a year in. I really don't think you have any problem so long as you let it cure completely. No one should be surprised that uncured silicone harms their aquarium's inhabitants.

[Mhay]

Originally Posted by Khemul

But that's the thing. They don't. They make something that is relabeled "aquarium silicone". They don't make something specifically for use in aquariums.

There is stuff out there labeled Aquarium silicone. I have 3 tubes of it sitting in my loft. Is it a GE brand, no? Because that stuff killed everything I had even after curing for weeks. It is specifically from marine land and made for aquariums. If you want to give what you have a try, go for it, just make sure it cures all the way. But at the same time don't be surprised if your critters die. When I discovered it was my silicone that was the problem some people said to just let it cure longer. Well for 1 I'm not very patient when it comes to stuff like that, and second there was still no gaurentee. Fastest and best way around it: aquarium silicone. Done and done

[Khemul]

Originally Posted by Mhay

There is stuff out there labeled Aquarium silicone. I have 3 tubes of it sitting in my loft. Is it a GE brand, no? Because that stuff killed everything I had even after curing for weeks. It is specifically from marine land and made for aquariums. If you want to give what you have a try, go for it, just make sure it cures all the way. But at the same time don't be surprised if your critters die. When I discovered it was my silicone that was the problem some people said to just let it cure longer. Well for 1 I'm not very patient when it comes to stuff like that, and second there was still no gaurentee. Fastest and best way around it: aquarium silicone. Done and done

What I am saying though is that there is no difference between the stuff labeled "aquarium silicone" and the stuff you can get at the store. Marineland doesn't manufacture silicone. They relabel it.

The main thing "aquarium silicone" does is take the questions out of the equation. But it is simple, common rebranding. The price difference is entirely in the rebranding. For some people, that peace of mind is entirely worth it and I understand it. But there is no silicone made specifically for aquarium use. Even the stuff used to manufacture your tank wasn't made specifically for aquarium use.

[Mhay]

Originally Posted by Khemul

What I am saying though is that there is no difference between the stuff labeled "aquarium silicone" and the stuff you can get at the store. Marineland doesn't manufacture silicone. They relabel it.

The main thing "aquarium silicone" does is take the questions out of the equation. But it is simple, common rebranding. The price difference is entirely in the rebranding. For some people, that peace of mind is entirely worth it and I understand it. But there is no silicone made specifically for aquarium use. Even the stuff used to manufacture your tank wasn't made specifically for aquarium use.

Ahh I get what you're saying. Yes, it is just re-branding and takes the guessing game out of equation. I'm just speaking from experience and I don't wish what I went through upon anyone. To me it's well worth the money spent to know for sure that after the recommending curing time you can put fish in with out it leeching chemicals and killing everything off.

[James77]

A great post by uncleof6 regarding silicon I and II:

Originally Posted by uncleof6

The MSDS for Silicone II does not indicate that there are any additions other than siloxanes, of which there are literally hundreds, (polymers) common to all silicones, without getting to complicated about it, The MSDS also does not indicate any proprietary additives either. Where such is present, the law requires that they be included in the MSDS. This raises serious questions as to the validity of the advertising.

What differentiates Silicone II from Silicone I is the latter is an acetoxy cure silicone, and the former is a neutral cure silicone.

Silicone II does not take longer to cure; published cure times are about the same. However the cure times pertain to a specific amount of silicone, usually given in a bead size, generally 1/8" or 1/4". Hardly have I ever seen an aquarium application use that little. As the amount increases the cure time increases, a week, two weeks...RTV100 series' 7 day full cure time is for a 1/4" bead!

I would say that neutral cure silicone is a bit more toxic in its "uncured" state than acetoxy cure silicone, but that is as far as it goes. It is better to malign a product for what it does not do well, rather than internet rumor.

Acetoxy cure silicone excels at bonding to glass and ceramics; acetic acid is corrosive, so it is not suited for metals, and it does not bond well to other materials (acrylic included.) Neutral cure excels at bonding metals (non-corrosive) and other materials (acrylic not included.)

Co-polymers, are another category (not 100% silicone) and are out of the scope of this thread.

Within the two general categories, there are several sub-categories: sealant, adhesive, high temperature, etc. Obviously we are only concerned with sealants and adhesives. the choice of which to use, really takes little thought. Sealants seal, adhsives hold stuff together.

GE Silicone I (Momentive) is, easy to work with, but is a bargain basement low end sealant. RTV100 series (Momentive) or SCS1200 (Momentive) are high end adhesives, not so easy to work with. In between there is a plethora of formulations, that will drive the most studious nuts ( I am a prime example .)

A short list has been publised at least a 100 times here on RC, not that they are the only choices, but everytime some off the wall silicone is asked about, or mentioned, it just adds to the confusion (and rumors.) In similar fashion "what is safe and unsafe" has been published at least the same number of times, over the past several years, here on RC.

Originally Posted by uncleof6

I did not overlook anything. It is all a myth, the tank gets wiped out because folks don't let the neutral cure silicones cure long enough. In fact acetoxy cure silicone is just as toxic if not cured sufficiently. It is almost hysteria over "mildew resistant." Neutral cure silicone is naturally mildew resistant because it IS neutral cure. I have poured over MSDS after MSDS no such additive is present.

No offense taken, but it is fascinating how folks will religiously defend a myth, yet not bother to support the recommendation that has existed since I entered the hobby some 30 something years ago:

100% silicone (no co-polymers such as acrylic)
Acetoxy cure (because it sticks to glass better than neutral cure)
FDA approved for food contact
Suitable for the task at hand (a structural adhesive for holding things together, and sealant for simply sealing something)

Is FDA approval really necessary? Not really, but as many times as the question "is this silicone reef safe?" gets asked (multiple times per week) you would think this would reduce the amount of questions...no such luck. When the myth is more popular than the truth, print the myth—it makes for more exciting threads...

Originally Posted by uncleof6

Important Notice!! Full cure time for this product is 7 - 14 days, and depending on usage—longer.

http://reefcentral.com/forums/showpo...2&postcount=11



As far as reef safe goes, all silicone is reef safe once fully cured. It is insufficient cure time that wipes out tanks, not fully cured silicone with the "mythical" bio-seal. Such additive is not listed in ANY documentation, which is required by law if such an additive is present. The difference between Silicone I, and Silicone II: Silicone I is an acetoxy cure, Silicone II is a neutral cure. Neutral cure silicones excel at sticking to metals, will looses adhesion with glass (relatively speaking) whereas Silicone I is corrosive, and not really good for use with metals, but adheres to glass better than neutral cure silicones. In the end though, they are both bargain basement low end consumer grade sealants that really should not be in an aquarium, but many use it anyway.