Need a silicone expert, sealant vs adhesive

[fullmonti]

I have just completed an aquarium 60x30x12" tall. Before starting this project all I ever heard was clean the glass good & always use 100% silicone with no additives like fungicides.I bought some aquarium silicone from Dr. Foster & Smith cleaned the glass first with Windex & then acetone just before assembly. After it was done I then heard there was sealant silicone & adhesive silicone & the adhesive is stronger & should be used for building aquariums. You guessed it, the Drs F & s is sealant silicone.

My question is sense the water level will only be 10" & the glass is pretty thick 60" sides 1/2" & 30" ends 3/8" so there is a wide glue joint, will the sealant silicone be strong enough AKA hold together??? I have already done a leak test & all was well, but that was just for a day.

As you may also have guessed I'm pretty much freaked out over all this

Jim

 

[MacWilliams]

I used sealant on my 40 gallon long aquarium and it holds together without a problem.

 

[SGT_York]

what type of bracing do you have?

 

[fullmonti]

None.
I don't think (& was told) any bracing is needed, water's only 10' deep & 1/2" glass.

This is a odd tank. It's really a paludarium, which is a terrarium with a major water feature. So there is sliding glass doors on top the tank & top is closed in. The whole thing is 48" tall, but only 10" of water & the bottom where the water is is the only 1/2" thick part.

I have a saltwater tank too & knew this site would be the best place to get info about the silicone, even though this one will be fresh water.

Jim

 

[uncleof6]

I have just completed an aquarium 60x30x12" tall. Before starting this project all I ever heard was clean the glass good & always use 100% silicone with no additives like fungicides.I bought some aquarium silicone from Dr. Foster & Smith cleaned the glass first with Windex & then acetone just before assembly. After it was done I then heard there was sealant silicone & adhesive silicone & the adhesive is stronger & should be used for building aquariums. You guessed it, the Drs F & s is sealant silicone.

My question is sense the water level will only be 10" & the glass is pretty thick 60" sides 1/2" & 30" ends 3/8" so there is a wide glue joint, will the sealant silicone be strong enough AKA hold together??? I have already done a leak test & all was well, but that was just for a day.

As you may also have guessed I'm pretty much freaked out over all this

Jim

Correct cleaning is acetone, (or MEK,) with a final clean using alcohol just before you lay the bead.....windex? good grief...

Will it hold? Unknown. What I do know, is that consumer grade silicones are not suitable for holding pressure vessels together. Size is irrelevant for the most part.

 

[fullmonti]

I heard back from Marineland Aquatics which is who makes/sells the silicone Drs F & S sells. They said they can't say not knowing how exactly I manufactured my tank but they make all their tanks with sealant silicone. Don't know if theirs would be considered consumer grade silicone or not, but that was encouraging.

I know no one can guaranty if any tank will hold together for the next twenty years. I was just wanting to know if this should or should not be OK. If not I could reinforce the seams by gluing with the adhesive type silicone a small strip of glass. It would not be as clean looking but if needed I could do it.

Jim

 

[uncleof6]

I heard back from Marineland Aquatics which is who makes/sells the silicone Drs F & S sells. They said they can't say not knowing how exactly I manufactured my tank but they make all their tanks with sealant silicone. Don't know if theirs would be considered consumer grade silicone or not, but that was encouraging.

I know no one can guaranty if any tank will hold together for the next twenty years. I was just wanting to know if this should or should not be OK. If not I could reinforce the seams by gluing with the adhesive type silicone a small strip of glass. It would not be as clean looking but if needed I could do it.

Jim

NO THEY DON'T! Marineland does not make silicone, it is manufactured by Dow Corning, and it is unsuitable for use in aquarium building. Aqueon tells the same story about their branded silicone: "Same silicone used to build our tanks." Yeah right, I went through there and saw the cartons and drums of Momentive RTV100 series silicone. No manufacturer will say aquarium use is ok, granted, save ONE: Momentive, that states that successful aquarium applications have been achieved with SCS1200, a high adhesive strength industrial adhesive.

They are right about one thing however, it depends on your skill as a builder.

 

[fullmonti]

OK two things seem clear. I'm not a professional tank builder, & I used less than the best product for the job. I'm not a dummy though & I usually do a good job of what ever I do. If I ever build another tank I know what to use now. At this point the thing is already together & I know some times less than ideal will still work. I'm trying to figure out what I should do now. So please ask questions about details if needed, was hoping for positive suggestions.

Jim

 

[ca1ore]

Fullmonti, I built a tank of similar depth to yours a long time ago, and while my length and width dimensions were somewhat less (48x24 in fact) than yours, it held together just fine with standard off-the-shelf silicone. I would not personally attempt it again, nor with a large tank, as I simply don't know enough about building tanks, but it was kind of fun. I have always heard that it is height that determines the pressure on the seams, and that length and width are irrelevant, except for the degree to which the glass bows, but I'd defer to those more experienced and knowledgeable than I for a definitive view.

 

[kegogut]

Silicone should hold your tank NP with the depth your doing. Silicone will hold glass together with easy. Ofcourse acrylic is a different story.

 

[fullmonti]

ca1ore, I agree with all of that. If this was just the four sides glued to the bottom I'd cut it apart, clean it up & redo it using the better stuff. That is not the case though. You wouldn't believe how many other pieces of glass are glued to the four sides. Taking it apart is not a practical option at this point.

I really do think this could be OK as is. Obviously don't want to take the chance. I'm really ****ed-off that I never heard any of this before. Also ****ed at my self for not doing more research. I usually do but like I said all I had ever heard was clean the glass good & use 100% silicone with no fungicides.

All I can think of at this point is to trim the silicone off the inside bottom seams & glue (with the right stuff) a piece of glass (1" to 1 1/2" wide) in the joint to reinforce the joint. One whole end has a overflow which already has an extra piece of glass reinforcing it. If needed I could glue a reinforcing piece up the other ends seams. Does this seem a reasonable plan, or any other suggestions???

Thanks
Jim

 

[jimmyj7090]

Tough situation. The only way to know if it will fail is to set it up and wait. If it doesn't fail everything will be great, but if it does fail you will likely have an incredible mess on your hands in addition to any livestock that will probably be lost.

Are you a gambler?

 

[fullmonti]

Short answer, not really. I think there is a better than even chance it would be fine, even long term. When I think of the the consequences it doesn't seem worth it.

Guess sense there where no real suggestions, just some kind words of support & a bit of a silicone tutoring. I'll continue to muddle through & do some reinforcing like I talked about.

Thanks
Jim

 

[coseal]

why not just order some momentive rtv? and redo it? a little elbow grease for piece of mind seems like a fair trade off to me.

 

[fullmonti]

That's pretty much what I said I was going to do. Ready to call Grainger on Mon to get a tube of the good stuff.

 

[jimmyj7090]

Lots of work, but that's what I would do. Assuming you do get the RTV100 series and re-do it, make sure to check the date code on the tube(s). It's not uncomon for the stuff to be shipped out past it's prime.

I don't recall how to decipher the codes, but if you search uncleof6 's reccent posts he explained it in another DIY thread reccently.

 

[fullmonti]

Thanks I'll do that.

 

[jimmyj7090]

It might take a while. I started going through Jim's (uncleof6) posts and couldn't find where he explained the date codes. I may have been wrong about how reccently he posted that info.

Maybe try shooting him a PM and asking him about it.

 

[fullmonti]

I found it. Thanks

 

[fletch999]

After it was done I then heard there was sealant silicone & adhesive silicone & the adhesive is stronger & should be used for building aquariums. You guessed it, the Drs F & s is sealant silicone.Jim

You are talking about the same thing, silicone is an adhesive. adhesive silicone is 100% silicone and so is silicone. It doesn't matter how they market it. unless you mean acrylic silicone which is water cleanup so it would not work under water. I would not use RTV, it is for gasket making in engines. JMO