Quote:
Originally Posted by mcox
Is GE RTV 108 and GE SCS 1200 safe to use? By that I mean, will the compounds used to make it leach in time out into the water and poison the inhabitants?
Anyone know what the Adhesion and/or tensile strength is for RTV 108? I can find that the 1200 series has a tensile strength of approx 485 psi, but can't find anything on the RTV 108.
I read somewhere that most of the strength in a glass to glass bond is in between the panels where glass touches glass and that the interior seam is mostly there for looks and some protection from compromising the glass to glass seals and likely some additional leak protection. That being said, it seems to me that having an additional bottom interior perimeter bracing using 2-4" glass might actually help prevent seal failure.
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As far as the RTV108 being safe, all I can say is that once I finally got through to an honest to gosh silicone guru at GE, he said it was what aquarium manufacturers use. So IF I'm repeating that accurately, and IF he really knew what he was talking about, then I think it is a good assumption that it is safe for fish.
As far as the tensile strength is concerned... tensile strength is almost irrelevant. The cheap, over-the-counter "aquarium" silicone apparently have sufficient tensile strength. The issue is adhesion strength. Not tensile. And that is apparently where RTV108 shines.
As far as the bottom interior brace, apparently an additional layer of bottom glass is often used - maybe for the reasons you suggest. I honestly do not know.
Quote:
Originally Posted by greenleaf888
scolley I seriously considered building an all glass aquarium, but ultimately decided against the idea. I found price wise it really wasn't much cheaper and depending on size, it can be a gamble to say the least.
I must say I find it interesting how so many people want a flawlessly seamless aquarium and the risk they are willing to take to achieve this. I for one wouldn't dream about making an aquarium without bracing, deflection equals bad news in my books. As for the silicone, I don't believe making such a fine bead is a good idea. Cosmetically I think very few people would pay attention, let alone appreciate such a fine detail, so why risk catastrophic failure? I personally believe one contribution to your initial failure was a result of trying to have such a fine silicone bead. DIY is all personnel preference however, and I must thank you for the in depth article and your attention to detail. Your finished product looks amazing, one of the best I have seen. And you defiantly did your research, I know I picked up a few intriguing tips.
If I were going to build an AGA I would build spacer blocks. You could make them slightly larger than your end pieces to achieve a perfect silicone seem with a nice consistent thickness top to bottom. I would also probably not use clamps, as you stated earlier you risk pushing all the silicone out of the seem with to much pressure. Also many articles I have read suggest that using tape is the best method, you only really need to hold it all together with light pressure while the silicone sets.
Anyways I thought I would revive this thread with my two cents, as it was a really interesting read. My big DIY project will be a 220 gallon glass plywood tank. I know many planted tank enthusiasts don't really appreciate glass plywood tanks and would much rather have a flawless glass box which is very attractive, but for me it's an issue of what is more reliable and practical. Besides that I am a carpenter, so a glass plywood aquarium is right up my alley.
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Building yourself is definitely not always going to be cheaper. Shipping cost will make a big difference - if that applies to you as it did me. I had a special requirement - all glass, small seams, low iron glass, with holes drilled in the bottom. It was the last part that was the kicker. I would strongly suggest anyone buy a commercially built tank instead - if you can get one that fits your requirements.
Spacer blocks seem like a good idea. I've not seen it done though. As for tape vs. clamps, well that depends on how far you crank the clamp. And silicone is like grease on glass, and once that glass get's 1/2 inch thick, it gets heavy. It WANTS to slide around - big time. I believe all the tanks I've seen done with tape have been much smaller and/or thinner glass. I made a smaller tank with tape. It's easy with as small tank.
But if do it with tape, please post your results. Good luck.