Adhering acrylic to glass rimless aquarium

[Optimist1979]

Hello! I'm planning to convert a glass rimless aquarium 36x24x18 to an all-in-one aquarium. I basically have a 5 sided acrylic internal overflow (30x5x18) with baffles that i plan on adhering to the back corner of the aquarium. I will be using dow corning 999a silicone to bond the ajoining surfaces and at the seams. Should i be concerned about causing stress on the rimless tank by bonding the acrylic to it? As the silicone cures, will it shrink and pull together the glass and acrylic? Thanks!

[sleepydoc]

Bonding glass and acrylic. Is difficult at best. There are few products that even claim to do it and very little experience in the DIY community with them. Your best option would probably be to use bulkheads and gaskets, like a glass holes-type setup.

See this link: http://www.reefcentral.com/forums/showthread.php?t=2261709

[bmkj02]

It will hold for a short time. Maybe less than a year. I tried it on two tanks at the same time and about a year later had to pull it all apart and start over. If its a glass tank your best option is to go to a glass shop and have the pieces cut to fit. The Silicone will then last forever. Im going on 5yrs now with no problems.

[Optimist1979]

The acrylic overflow will have 4 sides and a bottom - it is designed hold water on its own. It will actually be resting on the bottom of the tank. Imagine shrinking your acrylic sump so it fits perfectly on the back corner of your display tank and creating a weir so water flows into the first chamber. I just need the silicone to hold it in place.

[sleepydoc]

If it's all internal, a bead of silicone around the edge should do it, as long as you realize that all it will be doing is wedging the box in place. (It would have to be in the corner as well)

Not sure why you don't just build it out of glass, though...