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Discussion Starter · #1 ·
Can the regular GE silicon be cured in a humid environment? Will a humid environment do any negative things to the cure? If the answer is yes, I could lower the humidity but it would be easier for me to just apply the silicon in the tank as it is. I would take the animal in the tank out for 48 hours, because I think the fumes would be bad for him.
 

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I guess it depends on what you mean by humid. My recollection is that silicone requires water in the air to cure, so that doesn't seem to be at odds with a curing environment. On the other hand, I don't believe that I would apply silicone to a wet surface so if it's that "humid" then that might be too much :) And you are right that you shouldn't put an animal in a tank that you can still smell the silicone strongly, even if that's more than 48 hours.

Just by way of reminder, too, make sure you are using GE Silicone 1 not Silicone 2; the latter has orangotins for the curing mechanism that are proven enzyme inhibitors. GE also seems to mess with their forumulas periodically so who knows if even Silicone 1 is still safe (there was a troubling 1* on the last tube I bought rather than just a 1). Probably best to use some sort of food-safe or aquarium sealant rather than any silicone you would buy at a big box store.

Mark
 

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Yeah, the glass would be completely dry. I was annoyed that GE had to mess up the silicon 1, I remember it used to have no mold inhibitors, but now they have modified that. My thought on it is that after about 72 hours once the whole curing process is done, as long as nothing is exposed, it should technically be safe, right? I was thinking about the aquarium stuff, but it’s just so expensive. And it can be argued that dart frogs are an expensive hobby in general, but I don’t have any dart frogs. I only plan on making display tanks from now on. I’m pretty sure though, that the GE stuff I have right now is the stuff with no additives, just 100% silicon. They have definitely made this stuff harder to find, though. IMO, they should have kept the original stuff the same and just created something like GE silicon 3 instead of changing the existing stuff.
 

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I'm afraid that just because the organotin-based silicone is cured, that is not proof against effects of the chemical. They are mobile after curing, according to my immunotoxicologist friend. The mold inhibitor stuff is just marketing, as is the 100% silicone. Neither are reliable indicators of safe silicone. If you buy online, I think you are talking just a couple of bucks difference between aquarium sealant and big box store prices for the unsafe stuff. That is not worth the dice roll on whatever the big box store has in stock, in my opinion. If you don't plan on putting animals in there, it could be irrelevant, but if I had a well setup vivarium sitting around, no way that wouldn't eventually have animals of some sort in there. Just buy the right stuff onliine and hold off a couple of days on your build. That's the safe route.

Mark
 

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Yeah, the glass would be completely dry. I was annoyed that GE had to mess up the silicon 1, I remember it used to have no mold inhibitors, but now they have modified that. My thought on it is that after about 72 hours once the whole curing process is done, as long as nothing is exposed, it should technically be safe, right? I was thinking about the aquarium stuff, but it’s just so expensive. And it can be argued that dart frogs are an expensive hobby in general, but I don’t have any dart frogs. I only plan on making display tanks from now on. I’m pretty sure though, that the GE stuff I have right now is the stuff with no additives, just 100% silicon. They have definitely made this stuff harder to find, though. IMO, they should have kept the original stuff the same and just created something like GE silicon 3 instead of changing the existing stuff.
GE Silicone 1 and 2 have no bearing on whether they are safe or not, they only indicate the curing agent. Both are safe to use as long as they do not have mold inhibitors added. Best indicator, if a tube does not indicate the additions of mold inhibitors, is to look at the guarantee. A 7 year guarantee is standard for 100% silicone with no additives. Anything higher likely has some additives to help keep the silicone from molding over. Stay away from anything labelled for kitchen, bath or outside use.
 

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GE Silicone 1 and 2 have no bearing on whether they are safe or not, they only indicate the curing agent. Both are safe to use as long as they do not have mold inhibitors added. Best indicator, if a tube does not indicate the additions of mold inhibitors, is to look at the guarantee. A 7 year guarantee is standard for 100% silicone with no additives. Anything higher likely has some additives to help keep the silicone from molding over. Stay away from anything labelled for kitchen, bath or outside use.
This is notoriously difficult to pin down, Chris, but I am not sure about you statements on mold inhibition (you might be completely correct, I am just not sure). My understanding (mostly based on pumilo and Ed's research) is that the organotins have to do with the curing agent. I was told that the claims for mold inhibition are just a marketing ploy (or maybe a happy coincidence based on the difference in curing agent used) and may or may not be listed on the outside of the tube. Regardless, it's the presence of the organotin that matters (not what the tube says), so an MSDS needs to be consulted before you can tell. That I am sure about. That's why I have gone to just using aquarium sealant because that's the only way I can be sure.

The stuff about the warranty is new to me and that is good information. Do you have a source for that? It would sure be a lot easier to figure things out that way than to have to try to puzzle through the deliberately confusing MSDS documents.

Mark
 

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This is notoriously difficult to pin down, Chris, but I am not sure about you statements on mold inhibition (you might be completely correct, I am just not sure). My understanding (mostly based on pumilo and Ed's research) is that the organotins have to do with the curing agent. I was told that the claims for mold inhibition are just a marketing ploy (or maybe a happy coincidence based on the difference in curing agent used) and may or may not be listed on the outside of the tube. Regardless, it's the presence of the organotin that matters (not what the tube says), so an MSDS needs to be consulted before you can tell. That I am sure about. That's why I have gone to just using aquarium sealant because that's the only way I can be sure.

The stuff about the warranty is new to me and that is good information. Do you have a source for that? It would sure be a lot easier to figure things out that way than to have to try to puzzle through the deliberately confusing MSDS documents.

Mark
No, sorry, I don't have any sources I can cite.

GE silicone I uses acetic acid as a curing agent and GE silicone II uses ammonia (and part of that curing agent I believe is the use of organotins). There are differences in curing time (GE I cures much faster, for instance), and GE II has better adherence to a broader range of materials.

I've used both in the past, with no ill effects for fish and some amphibians, over many decades (this would be anecdotal, based on maybe ~100 builds over the course of ~15-20 years). I typically use GE I now (and have always preferred it), primarily because it cures faster. I can't guarantee either of these products is safe for frogs or tadpoles (I'm not a chemist!), but I do believe there is a general misconception that GE II is unsafe because people do not wait for the product to cure properly, and introduce animals and water, etc. before the product has cured. This results in dead animals, and pretty quickly (especially fish). I think the new GE II+ silicone actually has the same curing times as GE I now (I have never used GE II+).

I haven't read any studies that link the different curing agent from GE II to amphibian/amphibian larvae death, or specifically anything regarding organotins, especially over the long term. I suspect these are probably suspended within the silicone once cured, but probably do leech out over the course of time. Are they damaging? I have no idea. I think GE II MSDS mentions keeping it away from pregnant women, which could be an indicator.

I have been in contact with GE in the past. They do not recommend any of their products for aquarium use or use with any animals, and that is all they will say on the matter. I do know from talking to them that 100% silicone based products have a standard 7 year mold warranty, and anything above that has anti-fungal additives to help provide longer lasting product in damp environments. As I am not a chemist, I can't make any real headway into the science of the two products. I offer my advice based on experience alone and would always recommend reviewing the MSDS sheets for the products if you have concerns (they are a nightmare to understand sometimes).

If anyone was to ever ask what I would suggest: I would always say GE Silicone I. I think it is likely safer.
 

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Excellent, Chris. That's good stuff.

The only thing I would point out about your observations is that there have been no ill effects that you have seen. I read somewhere (can't recall where) that sometimes the impacts of organotins are not evident for multiple generations down the line. At that point, there would be no way any of us could point back to why there is some sort of breeding difficulty. Might be the silicone, might be something else. I know I would have forgotten all about what silicone I used in which tank.

I think because it is so difficult to get accurate information, it is just better to use aquarium silicone for our purposes. If you absolutely have to use a big box store product, though, GE I is better than GE II. I would still push people toward a silicone claiming to be aquarium or food safe rather than any of the GE (or other big box store brand) products. That's a decision all of us have to make for ourselves, though. Anyway, thanks for taking the time to write all of that down, Chris.

Mark
 

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Agreed, which is why I preface everything with "my experience" - again I have not done (or read) any long term study here to be able to claim anything at all, positive or negative.

From working in the retail industry, I would also point out that many of the brands you may see saying they are aquarium safe are made in the same factory, using the same ingredients and same curing agents.

Just some food for thought ;)
 
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