Dow silicone is not intended for continuous immersion.

[UncommonSense]

I figured I would post this as a bit of a PSA for those of us building our own tanks, or doing DIY water seals!

I reached out directly to the Dow Chemical Company; asking which, if any, of their silicone formulations would be ideal for large marine aquarium construction, with continuous immersion in water… here is their response, and my next step in hunting down the best performing silicone aquarium sealants on the market!

Does anyone have any other high performance silicone sealant brands they’d like to recommend? I’m currently using ASI 502 clear A, and have some Momentive RTV100 in the mail…

 

[Fish Fan]

I have used and had no issues with GE Silicon 1 that can be found at a typical home store. Do not get GE Silicon 2, which has extra mold inhibitors in it. I do know that many members here have suggested that the GE product isn't really the best to use. I've never totally rebuilt a tank using it, but I have resealed MANY tanks with GE Silicon 1, and I've had no problems. I've also been told here that just resealing the inside of a tank is not a good idea, so I don't know, but it has worked for me for years

 

[UncommonSense]

I have used and had no issues with GE Silicon 1 that can be found at a typical home store. Do not get GE Silicon 2, which has extra mold inhibitors in it. I do know that many members here have suggested that the GE product isn't really the best to use. I've never totally rebuilt a tank using it, but I have resealed MANY tanks with GE Silicon 1, and I've had no problems. I've also been told here that just resealing the inside of a tank is not a good idea, so I don't know, but it has worked for me for years

Ah, I looked into the tensile strength, peel strength, modulus of elasticity, and several other factors within the PDS for this silicone…

Unfortunately, it’s not nearly as strong as even ASI 502, which in-itself is about half as strong as some of Dow’s offerings in many performance aspects!

Also, GE does not recommend that this silicone is either continuously immersed, or used for aquariums!

I’ll definitely be reaching out to Dap, and several other manufacturers, and relaying my findings here!

 

[Fish Fan]

Ah, I looked into the tensile strength, peel strength, modulus of elasticity, and several other factors within the PDS for this silicone…

Unfortunately, it’s not nearly as strong as even ASI 502, which in-itself is about half as strong as some of Dow’s offerings in many performance aspects!

Also, GE does not recommend that this silicone is either continuously immersed, or used for aquariums!

I’ll definitely be reaching out to Dap, and several other manufacturers… I’ll really my findings here!

I get it, others have said the same, but I'm just saying I've used it for years

 

[Malcontent]

What does Red Sea use?

 

[Fish Fan]

@BeanAnimal is knowledgable here, maybe he could pop in and offer some suggestions.

 

[UncommonSense]

What does Red Sea use?

Some sort of weird two-part formula, ostensibly making it cheaper in bulk…

It should theoretically perform better as a two-part sealant, but I’m guessing they cut corners there to save some $…

 

[Fish Fan]

What does Red Sea use?

I'm guessing GE Silicon 1 lol!

 

[BeanAnimal]

Most common

Momentive RTV103 and RTV108

Dow Corning 795 / 999-A

And i think some folks use
GE SCS1200 or SCS2000

Sika may have a product, but the part number escapes me. Europe, likely their own stuff too.

There are other's -- many of them white label packages of one of the above.

Note: Notice header in the email "consumer solutions". The response is based on the channel that you used to ask the question and your context. The answer is to avoid liability. If you were a commercial enterprise, your contact would be different and able discuss commercial use, limitations and liability.

 

[Fish Fan]

Most common

Momentive RTV103 and RTV108

Dow Corning 795 / 999-A

And i think some folks use
GE SCS1200 or SCS2000

Note: Notice header in the email "consumer solutions". The response is based on the channel that you used to ask the question.

Thank you for your help here

 

[UncommonSense]

Most common

Momentive RTV103 and RTV108

Dow Corning 795 / 999-A

And i think some folks use
GE SCS1200 or SCS2000

Sika may have a product, but the part number escapes me. Europe, likely their own stuff too.

There are other's -- many of them white label packages of one of the above.

Note: Notice header in the email "consumer solutions". The response is based on the channel that you used to ask the question and your context. The answer is to avoid liability. If you were a commercial enterprise, your contact would be different and able discuss commercial use, limitations and liability.

Much appreciated!!!

I will do some further research!

 

[oreo54]

There are a few "recommended" silicones based on property and tank size.

This just happens to be "on sale" sort of at $9 tube.
https://kensfish.com/products/aquarium-silicone-sealant-clear-10-2-oz?gQT=3
Yea GE SCS1200 is also a good one .
$25/tube is off putting,.

For small tanks the silicone (besides the 100% part) isn't as crucial.
Many will list "not for aquariums" but it's more a "legal dept says to say this"..

 

[oreo54]

One more.. but no data..
https://www.chewy.com/aqueon-aquari...JAAYItYs-yC_Ob8tO19MNWq_NHwnmkHhoCTKUQAvD_BwE
I have a hard time not trusting an Aquarium manuf.. but..YMMV
For reference, doubt if "I'd" use it.

 

[BeanAnimal]

I forgot about the ASI product. They are their own manufacturer, and it is also quality and labeled properly.

No idea who makes the aqueon product, but they are a brand, not a chemical company. I would have to assume it is an OEM from above or Elkem, etc.

I don't know a whole lot about that trade, my experience was with polyurethane OEMs and blenders.

 

[Fish Fan]

Holy cats! When did the aquarium specific stuff get to be $20/tube!

I have also used this brand as I do prefer black to clear silicon, and I don't know of any black silicon that's aquarium safe that you can just buy at a hardware store:
https://krakenbond.net/products/krakenbond-aquarium-silicone?variant=43782663798965

 

[UncommonSense]

Yea GE SCS1200 is also a good one .
$25/tube is off putting,.

Still not as bad as Momentive, Wacker, etc! (Almost $40/tube!!)

I guess for me, the primary draw towards the nicer, higher performance silicones is one of inexperience; I like the silicone to operate as intended, despite not having experience with it for decades straight…

Also, it’s hard to say no to the performance of some of the nicer varieties when I’m rarely using over 10-30ml at a time for smaller jobs…

The “not for immersion/aquariums” side of things definitely looks to be for liability, based on what countless people have had success with… but, some are rated for immersion; there must be a reason for that!

I forgot about the ASI product. They are their own manufacturer, and it is also quality and labeled properly. No idea who makes the aqueon product. I would have to assume it is an OEM from above.

yeah I’ve been using exclusively ASI for a bit now; a fantastic product! (Though they did just get bought out, if I understand their website correctly… let’s hope the product doesn’t suffer due to it…)

I just know that there are better performing options out there! (At least on paper, that is!)

 

[BeanAnimal]

I just know that there are better performing options out there! (At least on paper, that is!)

100% Silicone is a rather generic term -- "Acetal cure" or "RTV" are a class. but the formulations and product properties can vary greatly. Think of 100% beef -- Even within "Grade A" there are huge variations in texture, flavor, etc. -- let alone numerous classes of beef, but it is all 100%

 

[UncommonSense]

100% Silicone is a rather generic term -- "Acetal cure" or "RTV" are a class. but the formulations and product properties can vary greatly. Think of 100% beef -- Even within "Grade A" there are huge variations in texture, flavor, etc. -- let alone numerous classes of beef, but it is all 100%

Well said!!!

This has been my biggest hesitation regarding actually doing structural work for other people… even if I follow the silicone manufacturers instructions to the letter; there is some amount of variability in the silicone itself… that said, it’s essentially impossible to put a “lifespan” on my work…

I guess that’s just a case of overbuilding and underestimating the lifespan for CYA insurance?

 

[BeanAnimal]

Personally - I would not do "work" for other people like that without an LLC and insurance and an agreed on set of terms about liability.

 

[oreo54]

For "fun"..
https://homeycons.com/will-silicone-sealant-cure-underwater/https://homeycons.com/why-aquarium-silicone-sealant-is-a-must-have-for-leak-free-tanks/
New to me brand (not surprising, lol).