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Discussion Starter · #1 ·
I constructed a 20 gallon vert for some variabilis. I used GS and cork bark for the background and covered the GS with ge silicone. After a month the smell was gone. Then I used dap household silicone, the kind for aquariums, to make my conversion kit and seal some things up. It has been over a week, probably a week and a half at this point, and it still smells of vinegar. It said it is safe for use with animals after 48 hours. At this point I just want to start planting and it will be a month at least before I put the frogs in. my question is does it still smell because it's not fully cured? I dont want to plant and have any issues, I want to plant and establish microfauna without having to worry. What do you guys think?
 

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Discussion Starter · #2 ·
Oh yes I covered the ge silicone with a coco and peat mixture.
 

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If it still smells of vinegar, it is not fully cured. The acetic acid is given off by the reaction polymerizing. If it still smells of it, there is some area that is not cured. What happened most likely is that you either got a bad batch of silicone (happens) OR you used too thick of a volume. What happens in this case, the exterior cures making a vapor-proof barrier that prevents the uncured regions below to cure. So it slowly, slowly still is curing, and in so doing continues to outgas. I bet if you tested the areas you'd find either it is still sticky/gooey or that there is an uncured region somewhere.

Either way, ooke around and test everywhere and see if all regions are fully cured. (Non-sticky, non-smelly.) My guess is somewhere deeper it is not OR you used a bad batch.

When I work with silicone, if it is not fully cured in the first 4-5 hours, I wait another 1-2, and if it's still not I chunk the rest of caulk tube, and whatever I used it on. Most of the time when a bad batch doesn't cure initially, it NEVER will. The crosslinkers or the catalyst degraded or partly reacted, screwing up the chemistry, resulting in a permanent sticky goo rather than the flexible semi-solid silicone polymer.
 

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Discussion Starter · #4 ·
I dont think, and hope, that it was a bad batch because it is fully cured in some areas, but I did use a liberal amount in some areas so I'm guessing that what it is, I will check again when I get home. The smell has substantially decreased since I did everything but when I put my head in the tank I can still smell it.
 

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You could have possibly purchased some bad silicone. I'd give it another week or two before taking any drastic measures, though.
 

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Yeah I would give it a few more weeks...if the smell keeps going down just go ahead and plant it...let it grow out for another 3-4 weeks smell should be gone..until then I would put a fan on it and spray it will help the process. At least thats what I do.
 
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Is it at room temperature or are you curing it out in the garage? Silicone will cure faster at room temperature and will also cure faster with some air movement.
 
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Discussion Starter · #8 ·
I had it in the garage for the first 24 hours then put it in the basement. No fan I just have it open. I just looked at it and everything seems cured, and it's not soft so I think it is not just the surface that is cured, but there could easily be a spot that might have not cured all the way through yet. I'm about to go trim some excess silicone right now to clean things up, maybe I'll find it then. Thanks for the feedback guys.
 

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If it still smells of vinegar, it is not fully cured. The acetic acid is given off by the reaction polymerizing. If it still smells of it, there is some area that is not cured. What happened most likely is that you either got a bad batch of silicone (happens) OR you used too thick of a volume. What happens in this case, the exterior cures making a vapor-proof barrier that prevents the uncured regions below to cure. So it slowly, slowly still is curing, and in so doing continues to outgas. I bet if you tested the areas you'd find either it is still sticky/gooey or that there is an uncured region somewhere.

Either way, ooke around and test everywhere and see if all regions are fully cured. (Non-sticky, non-smelly.) My guess is somewhere deeper it is not OR you used a bad batch.

When I work with silicone, if it is not fully cured in the first 4-5 hours, I wait another 1-2, and if it's still not I chunk the rest of caulk tube, and whatever I used it on. Most of the time when a bad batch doesn't cure initially, it NEVER will. The crosslinkers or the catalyst degraded or partly reacted, screwing up the chemistry, resulting in a permanent sticky goo rather than the flexible semi-solid silicone polymer.
Is there any way to force cure the silicone?
 

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Welcome to the board! That's a good question. I am unaware of a way to force silicone to cure. Maybe someone else will weigh in with a method. The only thing I know of to do is wait and maybe air out the location.

Mark
 

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I would put a fan on it and spray it
+1 - give it some water to work with, and get the air moving, and warm it up too. I usually mist my cure jobs, and I also like to put a wrung-out wet towel somewhere real close by, to keep the localized RH way up.

When I do silicone work in my herp room, which is quite humid and runs about 68 NTL - 77 DTH, honestly the stink goes away after maybe 12 hours tops. (But I take a lot of care to not lay it on thick. You neither need, nor want, thick.) Whereas, with bigger jobs or new construction that I do benchtop in the garage, which is cold as hell most of the year, man - the stink lasts for days.

My guess is you applied it too thick somewhere and there's an encapsulated pocket of goo that's having trouble curing. My experience with expired or "bad" silicone is limited - I learned my lesson and consequently never store a tube more than maybe 6 months (opened or not) - but from distant memory I really don't recall it smelling as much as "good" silicone. I suspect the reason is that the stink comes from the cure. If it isn't curing it won't stink, right? Makes sense to me...

Good luck!
 
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