abalone Posted December 14, 2007 Report Share Posted December 14, 2007 Hi, just noticed my middle brace has fallen off one side in the middle of my tank whilst I was doing a water change. The tank has a large flex so drained a bit of water out.Tank is 1500mm long 600mm high and 500mm wide at each end and is bowing to 510mm in the centre, glass is 10mm thick. What recommendations can anybody make? Is this very dangerous? I guess I could half empty it and try to clamp it and glue it back in place for a day or so. thanks for any help Quote Link to comment Share on other sites More sharing options...
evilknieval69 Posted December 14, 2007 Report Share Posted December 14, 2007 Drop tank level to at least halfway ASAP! It is very dodgy, and if you keep it full it will burst. Its not a small tank to be mucking around with either. I broke the center brace in my 250L tank, and it bowed out about 5mm (10mm glass) I dropped the water level, pulled it back into shape with a clamp and glued a new brace on. A couple weeks later i found that the bottom seam had popped out aswell, obviously from when it popped at the top. I ended up stripping the tank down to 5 bits of glass, and putting it back together fresh. Quote Link to comment Share on other sites More sharing options...
Barrie Posted December 14, 2007 Report Share Posted December 14, 2007 remove as much water as practable and reglue both ends of the brace. Silicone takes at least 1 day per 1mm of seal so at best it will take 5 days to cure... leave as little water as possible in the tank for all this time. If that seal has broken down, have a good look at the rest of the tank . The brace like that has a lot of work to do so you would naturally expect it to go sooner but its a good time to check it all Quote Link to comment Share on other sites More sharing options...
abalone Posted December 14, 2007 Author Report Share Posted December 14, 2007 thanks for that, I will buy a new clamp in the morning and glue it back in place. Quote Link to comment Share on other sites More sharing options...
Warren Posted December 14, 2007 Report Share Posted December 14, 2007 Place a 200-300mm strip of wood between each end of the clamp and the glass to distribute the pressure and avoid breaking the glass from point-loading... Quote Link to comment Share on other sites More sharing options...
Warren Posted December 14, 2007 Report Share Posted December 14, 2007 Just out of interest, I calculated the deflection you should be seeing on the glass. It should be 4.76mm. As both the front and back panels will deflect by the same amount, you should see double this gap between the end of the brace and position it has sheared off the brace (approx 10mm). Is the 10mm you've measure the gap between the brace and front panel or the actual bend in the front panel using a straight end placed alone it's front? Quote Link to comment Share on other sites More sharing options...
abalone Posted December 14, 2007 Author Report Share Posted December 14, 2007 Hi Warren, yes I will put the pieces of timber in to load share. As far as the other part goes, when I removed the lights to clean tank and change water I noticed the glass that sits on top between the lights and braces appeared crooked but upon closer inspection found the top middle brace still glued on at the back of tank and on top but the front had slipped down and was inside tank. I measured the flex using a tape at each end at the top and in the middleat the top. The flex appears equal on the back and front glass (so nearly 5mm each) I hope this is what you meant, Also thanks very much for the help, cheers Quote Link to comment Share on other sites More sharing options...
Pegasus Posted December 14, 2007 Report Share Posted December 14, 2007 Also don't forget, that the bracing strip joints spend their life being exposed... rather than fully submersed.. and often are attacked by the heat of (sometimes quite often).. very strong hot lighting... which would all tend to reduce the life of the silicone holding these parts. It tends to get a lot more brittle, or harder than the stuff underwater.... which IMO is why we often hear of top braces giving way... Some time back I had a five footer in the lounge which dropped the top strip into the tank... on the front only. (S/H tank we bought)... I used long sash clamps.. with (as suggested).. wood braces .. 2"x3" 50mmX75mm is good.. along the front and back, before gently taking all the bow from the glass.... (get some help for this)... and use FOUR CLAMPS. divided evenly. Borrow some... as they are expensive. The water had been reduced to halfway before doing this... then I removed the brace completely and "thoroughly" cleaned up the area of any old silicone.. both on the tank and the bracing strip,.. before replacing the strip and re-sealing. Don't rush to remove the clamps.... give it a few days to "fully" cure, and you should be sweet. If you are concerned... you can also bond an extra rectangle of glass across the brace at each end... so they finish up on the underneath of the top brace... and butt against the front and rear panes of glass at each end. (50mm wide by the brace width will do..)... which will give you an extra area to bond to. So to clarify this bit... Just sit the brace across the top as normal... (unsealed at this point..).. then .. with the brace still loose.. bond your two extra bits onto the brace ... but set them in slightly to allow for the thickness of the front and back glass... which might be say... 10mm... and this will create a sort of step.. that will have TWO areas that can bond to the front and rear panes.... and so give you a bit more security. You "can" of course do it without clamps... if you can get a bit of help. This way you use the strong sticky fabric tape... (usually silver)... that they use for joining carpet and such... (is it called Duck Tape).. or something over here...? Get someone strong to pull the front and back in so that they are straight once more.. (after the water has been reduced of course)... then stick the tape well down the back and front to hold it in position... (avoiding where the brace will go of course).... ensuring that the front and rear are dead true and square as you attach the tapes... A few strips across from front to back will hold it in place... and you can get this tape from a local hardware or the Warehouse for about eight bucks. Hope this helps... and good luck with the project. Bill. Quote Link to comment Share on other sites More sharing options...
abalone Posted December 15, 2007 Author Report Share Posted December 15, 2007 Worked a treat, thanks everyone. Quote Link to comment Share on other sites More sharing options...
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