Aquarium silicone sealant comparisons

[SantaMonica]

Not a tank, it's for our scrubbers.

The Dow 795 sounded good, but it's not recommended for food, and I'm trying to stay with food-safe:

Dow 795 Silicone Building Sealant - 10.3 Fluid Ounce Cartridge 795BL | PKsupplies.com

Dow 795 silicone sealant provides medium elasticity and is comprised of a neutral cure silicone sealant architectural grade formula

www.pksupplies.com

 

[Backfromthedead]

Not a tank, it's for our scrubbers.

The Dow 795 sounded good, but it's not recommended for food, and I'm trying to stay with food-safe:

Dow 795 Silicone Building Sealant - 10.3 Fluid Ounce Cartridge 795BL | PKsupplies.com

Dow 795 silicone sealant provides medium elasticity and is comprised of a neutral cure silicone sealant architectural grade formula

www.pksupplies.com

Huh...I know nothing about that application. I'm guessing you're gonna have a hard time finding a structural grade silicone that claims to be "food-safe". If there is a silicone that's been tested and used widely enough to be sure it would GE silicone 1.

 

[phelps]

I think the DAP silicone is the easiest to use. But I haven't tried too many different silicones.

 

[CANAMONSTER]

SCS1200 is the best choice for Aquariums especially large ones. It has the highest tensile and sheer strength

 

[jjohnwm]

Scs1200-fast set, cures 5-7 days, highest strength. Pricy.

Dow 795-slow set, cures 7-21 days, not as strong. Not so pricy.

Rtv 108-somewhere in the middle of the other 2 in all qualities. Some say it's the "ideal" choice. Also pricy.

The technical specifications for each of these adhesives can be found via quick Google search if you'd like to look over the data yourself. The key is finding what you can build with the best. I started with Dow 795 since it was so workable but have branched out to other quicker sets as I improved my building skills. Even though it doesn't spec out as strong as the others it is still quite strong. Here is a 200g rimless with dow795 that has ran continuously for 2 years with turbulent flow and minimal safety factor (5/8" side and bottom seams).
View attachment 1500018
And here's a 100g sump I built out of scrap glass this past weekend for a new setup.
View attachment 1500019

If I had it to do over (and i might), I would use a higher strength silicone for the big rimless tank and use perfectly cut and polished glass. The dow795 is perfectly fine for smaller projects like the sump that I cut up in my backyard.

I've never worked with rtv108 but a lot of people swear by it. Seems like a perfect medium of qualities just by reading the spec sheet though.

What size tank(s) are you building?

You, sir, do nice work. Nice taping, proper clamping...pre-drilling holes before assembly...no visible silicone globs on every surface in sight (unlike my builds)! Beautiful.

 

[Fish rescue]

Asi" also tested very hi strenth , if rebuilding over old silicone, I'd consider sanding all the edges with about 200-300grit

 

[Trouser Cough]

How do I estimate how much adhesive I'll need and how fat should the bead be? I've got a large glass tank that is 10'L x 4'W x 30"D that I need to reseal for the second time, probably because I didn't understand the difference in sealant vs adhesive when I did this a couple years ago. Very much looking forward to getting it right this time as this is a big piece of work that is a bummer to have gotten wrong. Any pointers appreciated and yes, I've read much of this thread. Not all... but a lot of it.

 

[Fish rescue]

Omg that's massive , if it's a old tank your going to want it completely disassembled, it's 3/4" I'm assuming , floor should be temperd, maybe not..

 

[Trouser Cough]

Omg that's massive , if it's a old tank your going to want it completely disassembled, it's 3/4" I'm assuming , floor should be temperd, maybe not..

I've had the tank for a five years. The guy I bought it from purchased it new and as I understand had it less than five years and never got it wet.

A couple years ago the tank leaked and yeah, it was a tough morning walking into the room and noticing that I'd be stacked up for a long time straightening that mess out. The wife is not a huge fan of the aquarium thing so it was a sort of multi-faceted morning; wet dry vacs at full tilt boogie, towels scattered everywhere, 30" fans howling, that awkward combination of wet masonry smell and zero conversation. I stripped the tank down to where the only silicone in it was not visible and I had assumed was acting as a cushion between panes. That BTW, was a lot bigger job than I had expected. What I didn't know was that there was a difference between silicone that went beyond color and mold additive. I put it on thick enough that tank buddies would come over and notice the seams. It lasted a couple years and pooped the bed in the middle of the night last weekend. I walked in Sunday morning to a flashback of two years prior though a little smarter this time as I knew not to use cat litter as an absorbent. That stuff was a huge mistake and I had stocked up a bunch of it just because I'm a belt and suspenders man (that doesn't own a cat but does have a Dobermann that would think cats are a gift from the gods).

As of tonight I have a bunch of Costco 26g storage totes doubled up with one inside the other just in case and they're full of water. Tomorrow I'll move fish into them for a more long term solution while I tear down the tank again. I also have a couple of 60g tanks and a 110g tank that I'm moving stock around in so I'll be able to house some of my fish uncomfortably for the month it'll take me to strip, source proper silicone, reseal, cure, etc. I have eleven FX6's so each will be well filtered.

What I don't want to do is botch it again.

What was in the big tank?

5 Peacock Bass
1 Black Arowana
4 Giraffe Catfish
1 15 year old armored pleco

These are all good sized fish and they will enjoy being in totes only slightly more than they would enjoy drying out on the floor.

And yes, I'm concerned about using the high zoot silicones that cure to the touch in just a few minutes. I've never heard of such a thing and am concerned about SCS1200 bonding to itself later when the floor bead is connected to the verticals. It will take a while just to do the four 31" vertical beads prior to even starting the seam around the floor of the tank.

460" of adhesive and a rookie at the helm. This has potential.

...and the adventure begins.

 

[Fish rescue]

Yes adventure, so my 2cents at the moment , so lots of people read these so im writing to beginners or pros ,if the tank does have reinforced seams (extra plates)...it should have ....find a glass man....and have the new pieces cut for you , step one