Crossbrace repair-FAIL

cryotek74 · Nov 13, 2015

My used 125 gal cross brace was not looking all that strong good. The brace is a 3/8" glass that is 8" wide. It was siliconed in place but the silicone had come loose. I thought I would redo it using Gorilla glue. "tough, expanding and sticks to everything" is what their website says. I used 80 grit sandpaper to rough up the glass. Followed the direction. The next day I went to remove all my bracing and clamps. I gave the aquarium a little pull and the glue failed to hold and the brace became loose.

What glues or adhesives have you all used successfully in the past to glue structural glass in place?? The aquarium is 72" long and 24 high so it does have a good amount of pressure pushing on the glass when full. My alternative is to build an aluminum cross brace and put across the top. Or i go full fancy and have a customer wood lid made with bracing integrated in it. Although I have used my budget for the project already.

Thanks in advance for the help.

ReefMadScientist · Nov 13, 2015

My man, superglue would not hold glass panes together nor any bracing

As you mentioned, you will have a lot of load on that glass so glue would not do.

I've used this before to repair a 150g tank that is still holding strong. You can get clear or black colorations. As for bracing, you should post up your plan so we can see if it will hold long-term.

kschweer · Nov 13, 2015

For the cross brace I would reccomend using RTV silicone. It is a silicone adhesive which is stronger than a normal silicone.

143MPCo · Nov 13, 2015

My first concern is why did the original silicon used come apart, it could have been for any number of reasons but my first guess would be someone used the incorrect type. If you aren't opposed to re-siliconing it, I would use a room temperature vulcanization silicone sealant like momentive rtv108. The bond strength (when fully cured) is second to none, care should be taken to not squeeze too much of the silicone out of the joint when clamping.

I will note that they're many brands of silicone that you will come across, research them! ...once FULLY cured most are reef safe, there is not enough information on mold inhibited additives to call them safe or unsafe but recommend you stay away from any that note the additive on the packaging.

You MUST remove any left over silicone/glue in order to insure yourself a proper bond, you noted you sanded the glass but, I would also soak a rag in acetone and let it permeate the area to be bonded in order to produce a clean surface before apply your choice of silicon.

cryotek74 · Nov 13, 2015

There is a plastic 2" strip across the top of the aqurium that is siliconed in and bound by the top rim brace. it has slack in it so it had slipped. The glass brace was siliconed in but it didn't look perfect so i choose to remove it and redo it. I've been weary of using silicone as it is a sealant more than a bonding and structural component. It looks like RTV108 is a very popular RTV to use in aquariums for its strength.