gully27 Posted February 25, 2015 Share Posted February 25, 2015 (edited) Hi all just after some hints and tips in a problem I am having with my bait tank I made. I made a aluminium tank with 2 windows in it so my little girl can watch the fish swimming around if she gets bored but I have used 5mm Perspex in it I bolted and glued it but it keeps cracking dose any one have any tips that could help me thanx Edited February 25, 2015 by gully27 Link to comment Share on other sites More sharing options...
Geoff Posted February 25, 2015 Share Posted February 25, 2015 Where do the cracks origionate from , the bolt holes ?? Do both sides crack or only one , if one , which side. When u fit new perspex how long before the cracking occurs , on the first outing or some time later Have u spoken to the perspex supplier about the problem Geoff Link to comment Share on other sites More sharing options...
Zacnoel Posted February 25, 2015 Share Posted February 25, 2015 (edited) Hi gully 27 My suggestion would be to replace the Perspex with Lexan , they are identical in appearance but with Lexan you can bend it in a vice or clamp and it will hold its shape. You can even belt it with a hammer and it won't break. It's tougher than Perspex and more maliable. If you purchased the perspex from a polycarbonate supplier they should be able to help. I'm not sure of the price difference but if you have to keep replacing the Perspex well ............$? . Also the tank looks quite large, I'm guessing between 80 and 100 liters, that's a fare bit of water preasure trying to get out, it may be as simple as the 5mm being to thin and the constant flexing and bulging of the Perspex as the boat moves is creating fatigue. As you would know, bend a piece of Perspex too far and it will snap or crack. Maybe 10mm is the go - good luck Edited February 25, 2015 by Zacnoel Link to comment Share on other sites More sharing options...
SquidMarks Posted February 26, 2015 Share Posted February 26, 2015 Can suggest to mainly attach the perspex using sillicon (do not use the bolts to tighten the perspex,its just there to hold it in case the sillicone fails, the sillicone will do the sealing and holding). That involves drilling holes in perspex that are larger than the bolts (smaller than bolt heads and nuts of course) and having the sillicone 'ooze' out of the bolt holes.This way, there is nothing to hold back the perspex from expanding/ contracting or the sillicone flexing if it needs to. In regards to water pressure.. water pressure on an object is proportional to the containers depth regardless of width. so unless the tank is really deep, water pressure should not be snapping 5mm perspex. Link to comment Share on other sites More sharing options...
gully27 Posted February 26, 2015 Author Share Posted February 26, 2015 Thank for all the help guys I have got in contact with a guy from a Perspex company and he is sending me some polycarbonate high inpact sheet and in 6mm and told me to drill the bolt holes 10% bigger then the bolt to if it dose flex it don't ride on the bolt so I will give this a go and see what happens Link to comment Share on other sites More sharing options...
Guest no one Posted March 2, 2015 Share Posted March 2, 2015 Are you sikaflexing the holes? Link to comment Share on other sites More sharing options...
gully27 Posted March 2, 2015 Author Share Posted March 2, 2015 Yer it will have sikaflex all the way around it I am going to try it with out drilling and bolting it and see if it keeps a good seal and don't leak Link to comment Share on other sites More sharing options...
Guest no one Posted March 2, 2015 Share Posted March 2, 2015 Mine leaks at the bottom, a bit but it's nothing major, I just stick the bilge on for 10 seconds every hour. Link to comment Share on other sites More sharing options...
chocolate Posted March 2, 2015 Share Posted March 2, 2015 I have a bait tank just a little bigger, But I don't have any windows. A few things I think could cause your problems, Your tank might flex a little, Your tank might not be straight / even on the front so when its put together it cracks due to stress, Also when drilling holes in Perspex even after tightening your screws due to stress/Harding slightly of sealer its cracks, When sealing the Perspex and the pressure on Perspex holes /screws /sealer/ tank not straight/ banging from hitting waves just presser on the boat its self can cause this there are lots than cause this. Sikaflex or MS1 from worth products is the stuff but its that good you don't need bolts. Sealing if done propyl will last for along time, In saying this I would seal inside and out. Sikaflex in white you can get 2 types one that goes hard quick and one slow and they have white, Get the slow curing one, Ms1 they have black and white but I only recommend black there is a difference with the 2 white is not as good. Ms1 is called windscreen sealer but is the same as Sikaflex. I at the moment am doing transmon repairs on my boat and I took of some brackets of the rear of the boat that had black MS1,took the screws out and used a scraper to take the bracket of and so did the outer layer of glass as well its good stuff if used correctly. Good luck. Link to comment Share on other sites More sharing options...
Zacnoel Posted March 2, 2015 Share Posted March 2, 2015 Did someone say preasure ? Link to comment Share on other sites More sharing options...
chocolate Posted March 3, 2015 Share Posted March 3, 2015 Yeh Zacnoel. What's the issue. Link to comment Share on other sites More sharing options...
Zacnoel Posted March 10, 2015 Share Posted March 10, 2015 (edited) No issue dude - I made the same comment in an earlier post and was hold that there is no preasure present in a bait tank. See the third and fourth posts Edited March 10, 2015 by Zacnoel Link to comment Share on other sites More sharing options...
chocolate Posted March 10, 2015 Share Posted March 10, 2015 Pressure on screws when tightening them up, It might be ok and look ok but after a while due to pressure on the screws and flex etc. It cracks, So it in my opinion just use sealers on there own. No prob Zacnoel. Link to comment Share on other sites More sharing options...
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