Glue for sealing acrylic baffles in sump?

[bizzmoneyb]

Does anyone know of a good safe acrylic glue that I could purchase at say a local hardware store.. home depot, lowes etc? I see tons at Lowes but im not sure which would be safe in an aquarium (which chemicals to avoid).
Im building a 20 gal sump now with 4 baffles. Id planned on just siliconing them in, but a friend of mine said he tried the same thing but the water pressure just pulled the baffles off, I guess because silicone doesnt really bond with acrylic. So i'd like to get a glue just to hold the baffles in place then silicone overtop of everything so its nice sturdy and water tight. Ive heard of using Weld On but dont think its readily available. Is that safe for water aquarium use?
Thanks for any help.

 

[natclanwy]

Is your sump glass or acrylic? If it is glass the only thing you can use is silicone, the trick is to build a fairly heavy bead on each side of the baffel at least a 3/8" thick so that it creates a channel for the acrylic to sit in. Make sure your baffles are at least 3/16" thick and you may want to glue a piece in between the baffles at the center. I used 1/4" acrylic and if the water level is low on one side of the baffle it bows out about a half inch one of these days I am going to cut a piece to fit between the baffles from top to bottom to help support the baffle and keep it from pulling away from the sides.
If your sump is acrylic then you will want to use weldon not sure which number though.

 

[bizzmoneyb]

Its a 20 gal glass tank with acrylic baffles. I planned to just keep them in place with alot of silicone but a buddy of mine did the same thing and said once he filled the tank the water pressure pushed the baffles out of position, I guess its just not strong enough and i believe silicone doesnt bond to acrylic. anyone else?
and weld on is safe and non toxic for use in water with living things? can you purchase it at a hardware store? seems its kindof only a special order type of thing.

 

[hurt]

I couldn't agree more with natclanwy, as long as you goop it on with a large bead on both sides it will work. I have a 20g glass fuge with acrylic baffles, that's 5 years old now, and the baffles have not budged one bit. You can't even see the seems now, because my fuge is covered in coralline. I have a 1 inch drop over the last baffle, so there is some pressure on it, and none have moved. Goop it on, and you will be fine. But if you don't think you can do that, Weld-on 1001 will work for glass to acrylic.

 

[natclanwy]

Your right silicone doesn't have a strong bond with acrylic which is the reason for the large beads on each side of the baffle. The extra silicone has an extremely strong bond with the glass and creates a channel that will hold the baffle in place, if your acrylic is too thin it will bow in the center and pull the panels out of the channel. I have built two glass sumps with acylic panels and neither have had the baffles come loose the first sump was in use for 3 years before I cut all of the baffles out and redesigned the sump this new version has been running for almost a year with no issues but like I said I need to support the center of the baffle because my baffles are 16" tall and when my sump is low on water the 16" of water on the other side bows the panel a little. This wasn't an issue on my first sump because my panels were only 12" tall.