Peggy, One of my water tanks has a split in a sharp corner caused by flexing of the tank when filled to capacity. This causes a leak when the boat heels. It is a 25 gallon tank and is built into the boat so removal and replacement means significant surgery to the boat. I'm thinking of replacing it with a flexible tank but wanted your recommendation first. Do you know of any way to fuse the material to stop the leak? Is it possible to use a soldering iron and melt the material in that local area? The split is about 2 inches long? Another option since it is on the top of the tank is to take a piece of poly board and screw it to the top of the tank with a gasket? Please advise on your approach to solve this one. Thanks much dave
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I don't think heat welding it will hold.
'Cuz the same flexing that caused the tank to crack will also break the weld. You could try putting a piece of poly down, with a rubber gasket under it, but I don't think that's gonna work if it's the vertical edge of a corner that's split. If you have enough access from the top to do that, you should be able to get the tank out and drop a new one in with minimal surgery to the boat. The best solution is a new tank. The only other solution that's likely to work is a bladder (ok for water)...but again--if you have enough access to the tank to cut it open and put a bladder inside and connect the fittings to your plumbing, you should be able to create enough access to the tank to remove it. Or...find another location for a water tank.
'Cuz the same flexing that caused the tank to crack will also break the weld. You could try putting a piece of poly down, with a rubber gasket under it, but I don't think that's gonna work if it's the vertical edge of a corner that's split. If you have enough access from the top to do that, you should be able to get the tank out and drop a new one in with minimal surgery to the boat. The best solution is a new tank. The only other solution that's likely to work is a bladder (ok for water)...but again--if you have enough access to the tank to cut it open and put a bladder inside and connect the fittings to your plumbing, you should be able to create enough access to the tank to remove it. Or...find another location for a water tank.
Short Term Fix
May I suggest the following as a fix. It may last for ever but is best viewed as a short term fix. Either way its cheap and worth a try. 1) drill a 1/4" hole at each end of the crack. This is to stop it extending. 2) Fill crack and holes with silicone rubber from a tube or gun. (It is not really for potable water but so little will ever be exposed to the tank water) 3) If deemed necessary make a metal or plastic strap or plate to cover the split and secure with self tapping screws with more silicone rubber. Otherwise its a new tank.
May I suggest the following as a fix. It may last for ever but is best viewed as a short term fix. Either way its cheap and worth a try. 1) drill a 1/4" hole at each end of the crack. This is to stop it extending. 2) Fill crack and holes with silicone rubber from a tube or gun. (It is not really for potable water but so little will ever be exposed to the tank water) 3) If deemed necessary make a metal or plastic strap or plate to cover the split and secure with self tapping screws with more silicone rubber. Otherwise its a new tank.
Clarification
Thanks for the responses. Just to clarify my tank has an indentation in the top of it that is rectangular in shape, right in the middle of the tank and it does not extend to the outer edges of the tank. It is about two inches deep. It is along one of these inside corners that it is split. My idea of a poly board was just to cover the whole indented area, my concern is trapping water in this area that will get pretty rancid very fast. I have access to get at the tank but the tank is too large to remove through the settee openings. I could cut it up and extract it in pieces but I don't think I can get a similar size replacement into the space. I might be wrong so I'll try to limp along this summer and make it a winter project for next year. I'll need to get it out to get the dimensions for a replacement from Ronco. Thanks again. The silicone might be worth a try to get through the summer. Dave
Thanks for the responses. Just to clarify my tank has an indentation in the top of it that is rectangular in shape, right in the middle of the tank and it does not extend to the outer edges of the tank. It is about two inches deep. It is along one of these inside corners that it is split. My idea of a poly board was just to cover the whole indented area, my concern is trapping water in this area that will get pretty rancid very fast. I have access to get at the tank but the tank is too large to remove through the settee openings. I could cut it up and extract it in pieces but I don't think I can get a similar size replacement into the space. I might be wrong so I'll try to limp along this summer and make it a winter project for next year. I'll need to get it out to get the dimensions for a replacement from Ronco. Thanks again. The silicone might be worth a try to get through the summer. Dave
same crack
I have what sounds like the same crack! Been living with it for 2 years. Haven't tried any sealers because I was told nothing would stick. What's that indentation for anyway? Please post whatever you do that fixes the problem
I have what sounds like the same crack! Been living with it for 2 years. Haven't tried any sealers because I was told nothing would stick. What's that indentation for anyway? Please post whatever you do that fixes the problem
Ooooh...idea (maybe)...
Without seeing the tank--and I'm having trouble visualizing exactly what the top looks like--I dunno if this will work or not, but since it's just an extension of the fix you asked about in the first place, it should: Cut the entire indentation out...put down a PVC, or poly (ethylene or propylene, doesn't matter) "cover" secured with self-tapping screws and a rubber gasket under it to seal it....which is the same way retrofit inspection port flanges are secured and sealed. That SHOULD be a permanent fix, and cutting out the entire indentation will also eliminate any water getting trapped between it and the "cover."
Without seeing the tank--and I'm having trouble visualizing exactly what the top looks like--I dunno if this will work or not, but since it's just an extension of the fix you asked about in the first place, it should: Cut the entire indentation out...put down a PVC, or poly (ethylene or propylene, doesn't matter) "cover" secured with self-tapping screws and a rubber gasket under it to seal it....which is the same way retrofit inspection port flanges are secured and sealed. That SHOULD be a permanent fix, and cutting out the entire indentation will also eliminate any water getting trapped between it and the "cover."
If this leak is not a critical seam,
or even if it is, you could try welding or get someone who does that. Harbor Freight has a plastic welder for about $20 that uses a compressor (not included). It consists of a heater like a big soldering iron but it has a hole through it where the compressed air blows out. You just heat the plastic with the heated air until it melts back together. It is really not that hard. You just need to melt it thoroughly and locally around the cracked area. You did not say what material it was made from. Is it polyethylene? If that welding doesn't work, you could just weld or bolt on a sheet of thick stiff plastic sheet. Look in the phone book for plastic suppliers. If you cut out the "indentation", leave some sticking down inside (maybe an inch or so) and run the new screws into that - but not through it. That will keep the screw hole bottoms from becoming a leak source.
or even if it is, you could try welding or get someone who does that. Harbor Freight has a plastic welder for about $20 that uses a compressor (not included). It consists of a heater like a big soldering iron but it has a hole through it where the compressed air blows out. You just heat the plastic with the heated air until it melts back together. It is really not that hard. You just need to melt it thoroughly and locally around the cracked area. You did not say what material it was made from. Is it polyethylene? If that welding doesn't work, you could just weld or bolt on a sheet of thick stiff plastic sheet. Look in the phone book for plastic suppliers. If you cut out the "indentation", leave some sticking down inside (maybe an inch or so) and run the new screws into that - but not through it. That will keep the screw hole bottoms from becoming a leak source.
Thanks
Peggy and Patrick, Thank you, great advice. Peggy you are a goddess as always. I can only think the indentation is for some mounting purpose, maybe a hold down device or to clear an obstruction in another application. O'Day probably got the tanks at a discount from an RV supplier or something. I have a tool like a rotozip that will be perfect for cutting out the entire top indentation section and I can leave generous low stress radii in the corners. A plastic cutting board from the local supermarket should serve the purpose to cap the tank with a gasket. Thanks again, Dave
Peggy and Patrick, Thank you, great advice. Peggy you are a goddess as always. I can only think the indentation is for some mounting purpose, maybe a hold down device or to clear an obstruction in another application. O'Day probably got the tanks at a discount from an RV supplier or something. I have a tool like a rotozip that will be perfect for cutting out the entire top indentation section and I can leave generous low stress radii in the corners. A plastic cutting board from the local supermarket should serve the purpose to cap the tank with a gasket. Thanks again, Dave
Removable Hatch
Dave, While you are cutting a hole and fitting a panel, why not fit a sealing hatch as is used on dinghy buoyancy tanks. My last boat came with one as standard and we could get into the tank to give it a good clean. You would be surprised the amount of bits that tanks accumulate over the years.
Dave, While you are cutting a hole and fitting a panel, why not fit a sealing hatch as is used on dinghy buoyancy tanks. My last boat came with one as standard and we could get into the tank to give it a good clean. You would be surprised the amount of bits that tanks accumulate over the years.
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