silicone cure time

[Alyssa]

I've made a custom background for my tank. I siliconed it in per the project instructions last Saturday, but the bead is still white, especially in places where it didn't get mushed against the side of the tank (meaning it's thicker there). Where it is thin most of it has cured to clear. Should I wait until it is all 100% clear before filling it, or is it OK to put water in now? Not that I'm eager or anything... *gnaws fingernails*

Thanks for any advice!

 

[Alyssa]

Well, my impatience got the best of me, and unable to wait any longer I put water in the tank. About 4" worth of water and a white cloud started billowing out from behind the custom background. I filled it all the way full and the water was totally cloudy. Sigh. BF says it was the silicone. I'm going to try hitting it with a hair dryer to see if I can force it to cure - after a week this is getting ridiculous. None of the pieces feel loose, so I don't even have a clue what I will need to do if I need to take the whole thing apart. Sadness.

On a happy note, the tank filling/draining device I constructed works great. So there's that. It's a little slow because I only used 5/8" I.D. tube, but I think that's still way better than bucket brigade. Mostly because I'm a lot older than I was the last time I ran tanks, and somehow those buckets seem a LOT heavier.

 

[mfdrookie516]

I have used silicone within 48 hours of applying it in the past with no issues. The smell will get considerably less once it's cured IME. 3-4 days should be sufficient. If you have a thick bead, it won't get very clear. I don't think the white you're seeing is related at all to the silicone.

 

[Alyssa]

Yeah, I figured a week was plenty of time. But I can't imagine what else could be white - the background is black, coated with marine resin, and I did not put substrate in yet.

 

[Alyssa]

Hm, this is odd. I am hitting it with a hair dryer and it smells rather like the kind of paste we used in kindergarten.

 

[mfdrookie516]

Did you make this background yourself, or buy it? I would contact the manufacturer if you bought it to see if this is normal. Pure, clear, silicone will not turn your water white, even if it's wet... trust me, been there, done that.

 

[Alyssa]

I made the background using the foam board - cement (3 layers) - marine resin method. I put the pieces in the water by themselves to see if they were causing it and they were not. It was definitely the silicone. I broke down and worked the pieces off. The places where the silicone was still white, the silicone was as wet and goopy as the day I put it on. Now, maybe I got bad silicone? I wiped it all off and scraped the globs off the tank (I didn't bother scraping the back down to perfect, figuring it'll just be covered up anyway.)

In some places, near the edges where they would have had a little circulation (not much really, but a bit) the silicone had cured pretty normally. So I'm thinking maybe put the pieces back in and then just put the silicone where it can be reached from the outside? Along the edges? So discouraged.

 

[Blueangel4730]

Sounds like the silicone was too thick

 

[Alyssa]

BF says it couldn't cure because it wasn't getting any air circulation. He thinks I should just use a few dabs of liquid nails to secure the pieces into the tank, but I've read elsewhere that liquid nails is not fish safe. He says once it cures it should be fish safe. He's a PhD chemist and makes his living working with environmental impact of chemicals so he's probably right. He told me the silicone wasn't going to cure the way I put it on, too, even though I followed the project directions exactly. I'm still torn though. Anyone ever used liquid nails?

 

[glassbird]

Never used liquid nails, so I can't help there. But let me ask a question about the silicone...what type did you use? Did it say anywhere on the label that it contained any type of mildewcide?

 

[Alyssa]

Derp!

Turned out I had the wrong kind of silicone. It had latex in it. So, I got the RIGHT kind and have glued it all back in. It's already in better shape than it was after the first gluing, so I'm not going to beat myself up [too much] [more]. Nothing but time, my pride, and the price of the wrong silicone lost so I guess in terms of learning experiences this one was not too painful. Onward and upward!