Used the wrong silicone??

[arejayy]

I know this topic has been covered extensively, but I wanted some clarification before I tackle my issue.

Just finished setting up a new 125g and had to drill and add an overflow to the tank. In doing this I used silicone to seal in the internal overflow. In my haste I used silicone with mildew resistant chemicals in it.

My question is this, if I run the tank for a month or more (without livestock)will the harmful chemicals in the silicone dissipate? It will take me days to re-do everything and Im sure it would be best to play it safe, but this is going to be a fish only setup and if I can get away with leaving it, it would help tremendously.

Thanks!

 

[Psicloner]

The contaminants will not dissipate over a month. they are designed for long term resistance to mildew.

probably better to start over before spending hundreds or thousands without peace of mind

 

[MstgKillr]

The contaminants will not dissipate over a month. they are designed for long term resistance to mildew.

probably better to start over before spending hundreds or thousands without peace of mind

I agree...

 

[gbru316]

remove and replace. You don't want that stuff anywhere near your tank.

 

[James77]

Some great posts by Uncleof6. The mold/mildew resistance comes from the cure type.

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

http://reefcentral.com/forums/showpost.php?p=21891202&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.

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...

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.

 

[ca1ore]

Hard to find fault with any of that. The only time I buggered up a tank was because I only waited 24 hours before using a silicone sump (just baffles using GE I).