To Re-Silicone or Not?

[evilpsych]

ok. So I just picked up a 75g All-Glass Aquariums tank from Craigslist.. The price was right, so I bought it. It was dry and had about an inch of atrocious neon colored rocks in the bottom.. Well, I got it home, and today I finally scooped out the gravel, and noticed the build date on the tank..

"April 28th, 1994" 'Built by Scott'... :eek:

Now, I've got it filled with water in my garage on the atrocious stand which will be discarded doing a leak test.. but still, 17 year old silicone? I've resealed tanks before, but what about the stuff that's in the joints of the glass?

[akunochi]

Water test it for a week and look at deflection in the glass if present. I would not break apart the tank and reseal it unless I had to. The RTV alone is almost 10$ a tube for the commercial grade stuff (RTV 100 series).

[cnapierala]

Yea, i have had older tanks that held just fine. Just fill it up and keep an eye on it for awhile.

[Drewbaby]

My 180 was built sometime in the 80's. The sticker was half torn. I failed to water test with no Ill effects. I did have the old school glass center brace fall into the tank and the front and back panels did bow approximately 2" each. They should have cracked. I woke up and was like... What is that in my... OH SH%T. I grabbed a siphon hose 8 buckets and two tie down straps from the bed of my truck and started the adventure. I drained the water then wrapped the straps around the tank and slowly cranked them down until the glass was back in "normal" position. I then re-siliconed the middle brace back into place. Two days later refilled and haven't worried since.

[Robert62779]

I would redo just to be on the safe side.. but it might not be worth the time and cost of silicone to redo.

[AcMonster]

I would redo just to be on the safe side.. but it might not be worth the time and cost of silicone to redo.

There is really no reason to re do it if it water tests fine. If it holds water for days just fine, it's time to enjoy the tank!

[akunochi]

I would redo just to be on the safe side.. but it might not be worth the time and cost of silicone to redo.

Just out of curiousity have you ever broken down a tank clean all the old silicone off and then repaired it? If not you can't possibly understand the man hours that go into cleaning old silicone off glass to teh point it is ready for fresh silicone.

[JTL]

Unfortuneatly I have had to repair a couple of tanks and it was a major PITA. If it doesn't leak and the seams visably look good just leave it. Or you could just reseal the inside seams to give a little added protection.

On a side note for those using RTV 100 series silicone you do not need to clean off all of the old silicone back to virgin glass. RTV bonds better to itself than it does to glass. I did not realize this until recently when I contacted Momemtive who makes the stuff. Another thing it is $7 for a 10oz tube at Zoro with only $5 shipping per order vs $12 at Grainger and much higher shipping.

[akunochi]

Yeah I prefer a clean glass plate to start with just because while the RTV does cross latch in itself silcone still does not bond well to old silicone. As far as the price I was just going off Grainger since it is local to me and I just pick it up there.

[JTL]

Clean glass is great but what a lot of work.
I would be concerned about non-RTV to RTV or non-RTV to non-RTV but it sounds like RTV to RTV is a winner. You could probably get it cheaper from Zoro considering there is no sales tax and have it delivered to your door and save the gas.

From: Arnold, Dave [mailto:Dave.Arnold@momentive.com]
Sent: Friday, August 19, 2011 11:37 AM
To: John
Subject: RE: Hexion Website Inquiry

John,
As long as you give the acetone long enough to volatilize off before applying the silicone (typically 15-30 minutes), you shouldn't see any issues with adhesion. Additionally, the silicone should bond to itself better than anything else (assuming there aren't any sediments/surface contaminants in the way).

-Dave

[jeosbo]

My thoughts are that if it holds after a week of leak testing then ther is no reason to go through the trouble. I have a couple of 55's a 75 and a few 20's that I have had since the mid 90's and still have no problems (knock on wood).
Because of the trouble involved I have actually turned down free 55's that were leakers...just didn't want to spend hours re-sealing them.

[Robert62779]

i have on a smaller tank... its not fun and the man hours might not be worth the time for a 75 gallon. IMO if the tank was 180 or above i would consider it. Im not saying this to discourage you from doing it..

[jeosbo]

i have on a smaller tank... its not fun and the man hours might not be worth the time for a 75 gallon. IMO if the tank was 180 or above i would consider it. Im not saying this to discourage you from doing it..

I would probably put the time into it for a free 75, but nothing smaller. Guess the moral is that everyone has a threshold of how much work we will put into a 'free' tank, for most I think it may be at or above a 55 though. And as for the op...I certainly wouldn't do it if it wasn't needed!