right silicone? pic
- Thread starter mayjong
- Start date
I understand the desire to save some coin, this is the DIY section after all, but with all the money spent on livstock, saving a few pennies on dubious silicone is moronic IMO. I can speak from personal experience that even the GE varieties that do not say 'mildew resistant' can nuke a tank. I built a new sump one time a and used the GE 5000 tube which I was assured was safe and came within a whisker of wiping my entire tank. As it was, all my LPS corals died within 2 days.
Too many people here who represent their opinion as expertise - it is not the same thing. I always use silicone specifically labelled for aquarium use - and let it cure for at least 72 hours.
Too many people here who represent their opinion as expertise - it is not the same thing. I always use silicone specifically labelled for aquarium use - and let it cure for at least 72 hours.
Khemul
New member
Which is basically the same stuff as people get at the hardware store, but with directions to let it cure longer.
In general though, yeah it is probably safer for people to just use the "aquarium safe" stuff and pay much more for better directions (I assume it costs a lot to reprint the label and that is why "aquarium safe" silicone is so much more expensive...). People assuming that the directions on the tube are even remotely useful as guidelines for aquarium usage leads to a lot of trouble.
Last edited:
uncleof6
Active member
First of all, there is no such thing as "Aquarium Silicone;" the product simply does not exist. Products labeled as such, are repackaged products. They are repackaged by minor distributors or major distributors, after receiving bulk amounts from major distributors or manufacturers.
You will not find a product in manufacturer information that is produced for aquarium use. Why? Because the product does not exist. One prime example of this is Aqueon/AGA. They repackage a Dow Corning product and label it "Aquarium." DAP, a subsidiary of Dow Corning, repackages a Dow Corning product, and labeled it "aquarium silicone," though it is no longer so labled. Both are nothing more than GE Silicone I, just a different manufacturer, both consumer grade (home depot quality) sealants.
Products labeled as Aquarium Silicone, are generally obtained through the supply line from Dow Corning. I have not found any matches in either MSDSs, or PDSs that would indicate these products are manufactured by Momentive Performance Materials (Formerly GE.) There are exceptions to every rule, however the most suitable silicones for aquarium use especially for structural work, are manufactured by Momentive, specifically RTV100 series, and SCS1200 series&simply due to physical properties—not opinion.
So what you are buying is NOT an aquarium silicone, rather a run of the mill consumer grade sealant in most cases, that has no relation to aquariums. Why? Because such a relationship does not exist. What you are buying is equivilant to GE Silicone I or II or a myriad of similar products of varying quality and usefulness, that are not manufactured for aquariums. Why? Because silicone products for aquariums do not exist, and are not manufactured.
It would be my suggestion, that rather than take pot shots at people, you do some research, and become knowledgeable about this subject, and hopefully you will come to understand the difference between opinion and knowledge—they are certainly not the same thing. Expertise comes from experience, knowledge comes from learning. The two go hand in hand. Opinion, on the other hand stands on its own, as it does not depend on either expertise or knowledge, it is just an opinion.
Didn't say there was - just that there are silicones LABELED for aquarium use and others not! In fact, the GE silicones are specifically labeled as not for aquarium use. My point, perhaps missed, is that unless you happen to work for either GE or Dow you don't know for sure, so it just seems to me to be 'better safe than sorry'. You take a different approach, perfectly fine.
No pot shot, just my own considerable experience. Everything on RC should be viewed as opinion, if it is couched in technobabble.
uncleof6
Active member
The problem here is that no silicone manufacturer labels said silicone for aquarium use. These labels are placed by middle level distributors, as in the case of Aqueon/AGA.
They "claim" this product is the same product used for their aquariums. Just a little fact finding research reveals that the product so labeled for "aqaurium use" is labeled by the manufacturer (Dow Corning) "not for use under water," and the silicone they use for their aquariums is manufactured by Momentive Performance Materials--stated specifically in the MSDS for the silicone they use for building tanks. Of course their PR (phone operators swear they don't use GE silicone.) A tour of the facility reveals the product they use to be: Momentive RTV100 series silicone, evidenced by the hundreds of cases of this product piled in their facility. Of course this product is also labeled: "not for use underwater." It really doesn't matter how it is spun, label or not, there is no "aquarium silicone."
Well perhaps, but it is more likely that when "gaps in knowledge" or "gaps in experience" are exposed, to use your wording: it usually does not elicit "technobabble", rather just plain "babble" about opinion.
Let's all just calm down.
What ca1ore said is that he uses silicone labeled for aquarium use, as he does not want to spend time wading through tons of pages about silicone. Kind of like LED lighting. He had a bad experience, and so plays it safe just in case.
uncleof6, you seem to know a lot about silicone, and what you recommend seems to be very practical. If you respond, then the OP can take your advice and save a few $. If not, then the OP can buy silicone labeled for aquariums form petco. But the problem with taking advice about stuff like this is that there might be 10 silicones at Home Depot good for aquariums, and 5 that are not. But if you don't know how to tell the difference, then you risk losing more. Thus, it's a good idea to understand why you buy something rather than just take advice.
What ca1ore said is that he uses silicone labeled for aquarium use, as he does not want to spend time wading through tons of pages about silicone. Kind of like LED lighting. He had a bad experience, and so plays it safe just in case.
uncleof6, you seem to know a lot about silicone, and what you recommend seems to be very practical. If you respond, then the OP can take your advice and save a few $. If not, then the OP can buy silicone labeled for aquariums form petco. But the problem with taking advice about stuff like this is that there might be 10 silicones at Home Depot good for aquariums, and 5 that are not. But if you don't know how to tell the difference, then you risk losing more. Thus, it's a good idea to understand why you buy something rather than just take advice.
uncleof6
Active member
There aren't ten silicones at Home Depot suitable for use in aquariums. That is one of the greater problems with this. Home Depot is cheap, but you get what you pay for.
A great deal of this depends on the intended purpose, but we are dealing with a product that degrades over time when emersed in water (not just gets wet, but is emersed) Home Depot sells the bottom of the pile sealants. They do not carry commercial grade, or "adhesive silicones." Not that are 100% silicone, e.g. are not co-polymers with things like acrylic, at any rate. There is only one "aqaurium labeled" silicone that meets the requirements for an adhesive. I would be very interested in discovering what the product really is. But, because there are two suitable "adhesive silicones" already known, and in wide commercial use and readily available, there is really no reason to pursue the fact finding further.
One forgotten (for the most part) little factoid, is that GE Silicone I used to be labled by GE as "Aquarium Silicone." Due to a myriad of lawsuits from disgruntled customers whose tanks fell apart, catastrophically, the label was withdrawn, and the wording "not for aquarium use" was put on the label. It is interesting to note, unless it has been added, that RTV100 series silicones do not carry this warning, and neither does SCS1200 series--and the SCS1200 is the only one where the literature indicates that "successful aquarium applications have been accomplished." Go figure, because they turn right around and say not for use under water.
Silicone is a rather simple subject, that gets overly complicated, mostly due to myth and legend, and yes a great deal of opinion. The same information has been posted hundreds of times here on RC, by myself and others, and still there seems to be this big desire to debate the topic.
For the 35 years I have been involved in this hobby, the basic recommendations for silicone have never changed.
1-Part 100% Silicone (no co-polymers)
Acetoxy cure (silicone II is a neutral cure—the only difference from Silicone I)
FDA approved for food contact.
Suitable properties for the appliction. (added to further limit debate)
The tough part of this, is learning what which silicone is good for, and what it had better not be asked to do. There are literally thousands of silicones around. Many of them fit the bill above. Many more do not. To help with the chaos, a short list was devised. It is posted many times here on RC. It includes both Momentive and Dow Corning products. DAP and Aqueon are both included in that list. So also is GE Silicone I.
From an objective standpoint, based on physical properties alone, GE Silicone I sits at rock bottom basement junk, and excluding the one I mentioned above, RTV100 and SCS1200 are sitting on top of the pile, based solely on peel and tensile strength—as well as meeting the criteria above. The ones sitting on top cost LESS than silicones relabeled to "aquarium silicone," and can be used to build tanks—big tanks, the ones labeled aquarium silicones are consumer grade sealants (based on physical properties) and it is a bad idea to build tanks with them.
The problem is, you cannot get these products at home depot, and the places you could get them, were mostly put out of business by home depot. (that is a different story for a different venue
)Which one to use, depends on the application. If you are sealing something, it really does not matter. You don't need the heavy hitters, but then why not, the price difference is negligible or less. If you are using it for structural purposes, you want something with more guts, hence the heavy hitters.
What is really frustrating, is tomorrow or the day after, someone will start a thread, post a picture of Silicone II and ask if it is reef safe. /: That is the net result of the need to continually debate this topic.
P.S. I am calm, been through this a hundred times....
I use GE Silicone I all the time, and have a sump over 10 years old with no problems. It works fine. Make sure it has no Mildew or mold resistance though. I saw a post further up that said it didn't mater. DONT LISTEN TO post #4. This topic had been beaten:deadhorse1: Do let it cure for 48 hours before testing though. If a sump splits its because it probably needed better bracing.
Last edited:
uncleof6
Active member
Care to enlighten us, as to what way it has been beaten? Care to enlighten us why 48 hours cure time is sufficient, when it is in direct contradiction to the Product Data Sheet? (based on the amounts of silicone used.) Care to enlighten us, based on physical properties, what supports your assesment, other than anecdotal information from your obviously vast experience in tank engineering and construction? Finally, would you care to enlighten us as to the nature and content of the products that "have mildew or mold resistance," and how this "content" might cause a problem in a marine system?
