GE1 vs GE2 silicone..whats the difference honestly?

[Trooper182]

So I posted on a FB group because I just got a aqueon 125g reef ready tank, stand, lights for a great deal. This tank is a early retirement gift to myself and I will be moving my 75g into this rank in 10 months when I retire from the army. It was suggested I reseal the tank to be on the safe side so I was asking if GE2 100% black silicone could be used and was given a resounding no. Was told use GE1 as it doesn't anti-mold additives. Thing is both tubes say mold resistant on them with the different being one is 10y vs 7y resistant. Also both tubes say not for aquarium use. Now I understand that 100% silicone is inherently mold resistant and the packaging probably says not for aquarium use to avoid liability, but if both packaging basically say the same thing, then why is GE1 recommended vs GE2? I decided to go with a sealant specifically made for aquarium use but am honestly curious about the GE thing.

 

[SliceGolfer]

From the search box:

Non-Reef Safe Silicone Disaster Cont.

How is this 100% Silicone and contain mold inhibitors?

www.reef2reef.com

 

[cilyjr]

Ge silicone 2 is the neutral cure silicone which will generally take longer to cure. It's less soluble to water and I believe that's why they say it sets in 3 hrs and able to get wet after that (not cured though they still suggest 24hrs for 1/8 inch bead) the reason I believe they suggest it is better for kitchen and bath is because acetoxy have a bad habit of yellowing white ceramic tiles. That's why the silicone I (acetoxy) is window and door only while silicone 2 (neutral) kitchen and bath.

 

[cilyjr]

Any silicone will be toxic and kill everything if it is not 100% cured. This can sometimes take a couple of weeks.

I tend to use Momentive RTV 100 series
102 is white
103 is black
18 is translucent

Momentive makes Silicone for a lot of the manufacturers that simply rebrand their products.

You can buy it online.

 

[Randy Holmes-Farley]

Any silicone will be toxic and kill everything if it is not 100% cured.

That's quite a strong assertion.

Why do you believe it to be true?

 

[Malcontent]

Check the SDS of both products.

People think 100% silicone is literally only silicone but it's just a marketing term to differentiate it from supposedly inferior silicone-latex blends.

100% silicone actually contains a variety of ingredients if you examine the SDSes...

 

[redfishbluefish]

GE Silicone 1 is considered the "safe" one (assuming you allow it to fully cure). I like a week cure. The difference between GE I and GE 2 is that GE 1 "cures" by reacting with moisture and giving off acetic acid (vinegar) smell, while GE2 cures by ammonia and methanol. GE2 got a bad rap for causing aquarium deaths....and I'm of the belief if you allow it to cure long enough, you'll be alright. But to play it safe, use GE1. The other silicone I use is the one for plastics. This one is great if your building a sump with acrylic baffles in a glass aquarium. You won't find it with the other caulks in the paint department of HD, you'll need to go to where they sell acrylic sheet goods. It looks like this:

Again, just allow it to cure. I've built multiple sumps with this silicone and never had a problem.

 

[MoshJosh]

Not helpful but. . .

My favorite brand has been Marine Land Aquarium Sealant sold at Petsmart (looks like you can get the big tube on Amazon). . . don't know what it is about it but it's my fav!

 

[ISpeakForTheSeas]

As mentioned, I've heard (but can't confirm) that GE2 is safe once fully cured, but it's generally recommended to go with GE1 just in case.

That said, the difference is what "Hazardous Component(s)" are in them (I don't know enough about chemistry to know based on the components what the real difference is, but someone else might).

GE2 "Hazardous Component(s)" as detailed in the SDS:
"Silica, amorphous, fumed, crystal-free 112945-52-5 >= 5 - <= 101,1,1,3,3,3-Hexamethyldisilazane 999-97-3 >= 1 - <= 5
Trimethoxy(methyl)silane 1185-55-3 >= 1 - <= 5
Carbon black 1333-86-4 >= 0 - <= 1
octamethylcyclotetrasiloxane 556-67-2 >= 0 - <= 1"

https://api.henkeldx.com/v1/mysds/SafetyDataSheetSet?Appid=%27YPSSW_SDSUA_EXT%27&Matnr=%272813670%27&Laiso=%27EN%27&Rvlid=%27US%27&Dmskey=%27%27

GE1 "Hazardous Component(s)" as detailed in the SDS:
"Silicon dioxide 7631-86-9 5 - 10"

https://api.henkeldx.com/v1/mysds/SafetyDataSheetSet?Appid=%27YPSSW_SDSUA_EXT%27&Matnr=%272795576%27&Laiso=%27EN%27&Rvlid=%27US%27&Dmskey=%27%27

 

[cilyjr]

That's quite a strong assertion.

Why do you believe it to be true?

Anecdotal accounts!

It's certainly a lot easier to say than any of the acetic acid leaching out of an acetoxy silicone during the curing process is going to have pretty dramatic effects on pH and tank health, especially in smaller systems where you are using a lot of silicone.

I see your point in dealing with absolutes though. Honestly, it's sort of a problem with the internet. We all get to say our piece whether we are experts or not. Btw we know each other, I'm from the Boston reefers society from back circa 2006.

 

[Randy Holmes-Farley]

Anecdotal accounts!

It's certainly a lot easier to say than any of the acetic acid leaching out of an acetoxy silicone during the curing process is going to have pretty dramatic effects on pH and tank health, especially in smaller systems where you are using a lot of silicone.

I see your point in dealing with absolutes though. Honestly, it's sort of a problem with the internet. We all get to say our piece whether we are experts or not. Btw we know each other, I'm from the Boston reefers society from back circa 2006.

I’ve never had a good understanding of what entities actually cause toxicity with silicone sealants, and under what scenarios.

Happy Reefing!