# Is GE Silicone II safe for marine aquarium use?



## Cypher

Hey Everyone,

As the title states, I'm wondering if any of you know if GE Silicone II is safe for use in Marine aquariums? Any experiences or opinions? Share please. Thanks.


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## drknight

IMO unless it says that it is aquarium safe I wouldn't use it. Spend a little more and get one that's aquarium safe could save you alot more in the long run.


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## xbacala

I used GE Silicone I as lot of people recommended. Work great.
As long as it said 100% Silicone is aquarium safe.


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## conix67

all silicone seal products say "100% silicone" I believe. Silicone II if I recall correctly are NOT aquarium safe, as they have additives for mildew.

Current products will NOT say aquarium safe even if it is. I heard this was because some legal reasons.

So you want something that does not have any additives such as mildew resistent.


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## Zebrapl3co

Yeah, I think all GE II are mildew resistant and the chemical is bad for your fish.
Ge 1200 series is the best kind of aquarium silicon you can get.
Try contacting John (sugarslidder), he used to carry alot of them. It's next to impossible to buy this from the stores now-a-days.
http://gtaaquaria.com/forum/showthread.php?t=14218

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## Riceburner

Window and door Silicone I is fine. Blue and white tube.


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## ameekplec.

Check to see if it is mildew or mold resistant. If it is, then it's not safe for aquarium use.


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## Cypher

Hmmm... I need black silicone. Thanks for the replies, will have to stop by the hardware store to see if they got GE silicone I in black.


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## wildexpressions

Cypher said:


> Hey Everyone,
> 
> As the title states, I'm wondering if any of you know if GE Silicone II is safe for use in Marine aquariums? Any experiences or opinions? Share please. Thanks.


I have used GE type I & II for windows and doors many times over the years although I no longer do and do not recommend them. It simply is not as strong as many other options. In a pinch I'd use it on tanks under 30 gallons but I'll never use it one over that.

In response to the poster that said as long as its 100% silicon it is safe that is not true. Silicone is a compound made up of a variety of silica based materials and the ingredients vary. That is why we have 100's of products designed for 1000's of uses and yet all are 100% silicon.

Below is a list of the ingredients that may or may not be present in the various Type II's and the range of percentages by volume for those ingredients according to the Consumer Products Information Database
Chemical 
Methyldimethoxy polydime-siloxane 068037-58-1 60-80%
Methyltrimethoxysilane 001185-55-3 1-5 %
Hexamethyldisilazane 000999-97-3 1-5 %
Octamethylcyclotetrasiloxane, silica reaction product 068583-49-3 10-30 %
Polydimethylsiloxanes (Silicon oil)	063148-62-9 10-30 %
Silanol/Siloxane polymers 068554-67-6 1-5 %

Momentive RTV 100 series, 800 series and SC1200 series are all far better products. All are avail in black and the last number indicates color

SC1200 is an excellent product that I have used a lot. It flows extremely smoothly and doesn't VOC you to badly.
Elongation	513%
Tensile Strength	480 psi

RTV103 is black & 108 is clear
Data sheet
Elongation 450%
Tensile Strength 400 psi

IS800
Data Sheet
Elongation 450 %
Tensile Strength 300%

SC1200 is sold as a construction sealant/adhesive and was available at Graingers 

Construction Distribution Supply. They have outlets in Scarborough, Toronto, Mississauga, Ktchener and Barrie.

This dude posted a message is 2006 on PN saying he had it and when I contacted him in 2009 he was still selling the stuff [email protected] He was great to deal with as well.

I'm not claiming to be an expert although I have used all of the listed products many times. I came by this information by talking to product engineers at Momentive which is the company that manufactures GE silicon products and by investigating what professionals use on the large commercial aquariums.


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## Cypher

Hey thanks for the reply and info wildexpressions. Have you ever used SC1200 for aquarium applications and do you know if its safe for marine organisms? 

I know of the thread you are talking about in PN, I contacted the guy only to find out his prices are now 2x+ what they used to be. In addition to that if I have to drive to pick it up, I might as well mail order the stuff or go buy from a store and end up being the same amount of money. So no more savings getting from the maurisil guy any longer. Thanks for the suggestion though. But back to the original question - is SC1200 marine aquarium safe? Thanks again.


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## wildexpressions

yes I've used sc1200 for aquariums. Actually that is the only thing I have used it for. I currently have maybe 19 aquariums in my store that were all redone with sc1200. 

I never use a used aquarium unless I strip and re-silicon it. I just just don't trust old silicon. I really like the SC1200 as it flows really smoothly. If you are good with a caulking gun it is an easy product to put down with out taping although I still tape clients tanks before doing them. 

I know that SC1200 is listed as a construction adhesive but it appears to be a commonly used product in the aquarium biz. Some of my old posts of PN indicate that I bought my first batch of sc1200 though North American Fish Breeders so maybe give them a call.

I personally think the number one reason for premature failure in re-siliconed aquariums is not cleaning the aquarium well enough. I believe that one well placed finger print is enough to cause a failure.

I've only ever had 1 failure over the years (GE type II) but it takes me approx 1.5 hr per 100 gallons of time to prep a tank and then approx 10 minutes per 100 gallons to actually do the job.


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## Reef_Aquatica

wildexpressions said:


> This dude posted a message is 2006 on PN saying he had it and when I contacted him in 2009 he was still selling the stuff [email protected] He was great to deal with as well.


I agreed, Michael is a great guy to deal with on silicon.

I also would recommend the 1200 series, even JOHN at NAFB uses that regularly to build his tanks, and he does build really HUGE tanks like 500G+ 8-10 feet ones.


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## Reef_Aquatica

*re-silicon tank*



wildexpressions said:


> I never use a used aquarium unless I strip and re-silicon it. I just just don't trust old silicon. I really like the SC1200 as it flows really smoothly. If you are good with a caulking gun it is an easy product to put down with out taping although I still tape clients tanks before doing them.


On another topic, how do you re-silicon used tank? You have to take the tank apart and then clean the silicon off the glass (what to use?)


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## cablemike

DONT TAKE IT APART! you simply want to remove the old silicone in the corners and around the base using a utility blade. and as far as applying the silicone, its an artform and i wouldnt recomend it to anyone who has not had experience with silicone.. you can make a mess of the tank if you dont know how to apply a bead.. you can use tape as an edge and remove it after but its not a nice as a skilled one shot bead.. i spend about three to four hours a day caulking so im kinda good at it


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## wildexpressions

yeah I agree, don't take it apart unless you have to and I also agree it is some what of an art form. A simple description of what I do is this. Others may do it differently with better or worse results but this works for me.

I tuck tape the corners together even though I have no intention of taking the tank apart. I remove the top plastic frame if there is one.

I use latex gloves to keep finger prints off the glass. I then use a pretty wide variety of different types and sizes of razor blades to clean out all of the silicon and once done go over it all with a fresh blade. Then I wash the seams down with a lint free rag and acetone

I then I go over the seams/corners with a real soft kleenex cause I find that if there is any missed silicon I will feel it pull at the kleenex as it moves over it. If there is some missed silicon I go back and remove it and then clean it with acetone again.

Although I do not tape my own tanks I do tape customers tanks. Do not put a large bead of silicon down as to large a bead weakens the bonds, especially in the short term. With a little practice the tape should only serve to act as a fall back in case of a mistake. In other words even though I tape it if I do the job 100% right there will be no silicon touching the tape.

Some people use a spoon to push the silicon into the seams in which case the tape will get covered in silicon but if you want it to look good when you pull the tape there can not be much silicon at the tape edge.

I usually only use a spoon on tanks over 150 gals and or if it split the seam. Keeping everything as clean as possible is IMO very important. That is it. It is simple.


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## Reef_Aquatica

Thanks for all the details  

I was thinking you have to take apart the glass panes and then wipe it clean. That's not so hard (after a few practise) 

Without taking apart the glass pane bonds, just applying new silicon on top (after wiping it), it is not really that strong. The strongest bonds that takes the pressure are the area where glass touches the glass.


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## gucci17

Reef_Aquatica said:


> Thanks for all the details
> 
> I was thinking you have to take apart the glass panes and then wipe it clean. That's not so hard (after a few practise)
> 
> Without taking apart the glass pane bonds, just applying new silicon on top (after wiping it), it is not really that strong. The strongest bonds that takes the pressure are the area where glass touches the glass.


You can take apart all the panels and reglue them but sometimes it's not needed. Depends on the condition of the silicone. Like you said, the strongest bonds are the ones that hold the glass together. Just be extra careful when taking it all apart. Not all glass is sanded/polished properly and can be sharp still or there could be chips that occured when a piece of glass that is flaked off is held in place by silicone and can cut you as well.

Wildexpressions has very good advice on resealing tanks.

Cablemike is right, a single bead does look nice. That's how I prefer it, plus it's less work having to tape things off. The only problem with that is on bigger tanks where you have to have a split seam. That's where compressed air caulking gun would do the trick lol.


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## Cypher

I cant seem to find the SC1200 silicone anywhere - is it made by GE?? What is the equivalent in other brands such as DAP - does anyone know? Thanks.


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## BillD

The 1200 series silicone is sold in cases, at construction supply places. Check back in this thread for a source. John's fish Food is another source. For small tanks and reseals 1200 isn't necessary. GE I for windows and doors is good, and the Rona and Home Hardware house brands are also good as they say "ideal for aquariums" right on the tube.


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## Cypher

Yeah, I cant seem to find GE 1 in black though. I did check both HD and Rona. No Homehardware near here.


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