my black holding tank  has a crack in it the width of the tank. this is not a sewege holding tank, holds the water from the sink in the kitchen. i tried a plumbers putty that is suppose to work on plastic and is waterproof. checked today and it didn't work, water is still leaking from the crack.

does anyone happen to know what might work to fix the crack?

or------what is the cost to replace one of these? it's a sundowner 7ft wide.

any help would be very appreciated.

okie ann

Buy a new tank.

Most other solutions just don't hold up because of the vibration that horses trailers put up with.

You can fix it, and it may last a couple months. But my experience is that it just won't last long term.

If you try to fix it. Make sure you clean it extremely well.  The grey water always contains a certain amount of grease. Even the natural oils off your skin as you wash. This gets deposited at the crack and prevents fiberglass resiens and other products from really adhering.

the tank is a plastic, not fiberglass or metal. the plumbers putty was suppose to work as it was waterproof i did clean it real good, looks like it didn't hold at all. this putty comes in a tube, called aquamend, underwater repair epoxy putty. now i see that it is for fiberglass,  last time i ask for help from a guy at home depot. will go back and see if i can get somthing else for plastic.

There are many types of plastics, and the glues for one may not be compatible for another. That's the point I was making with my other thread. You have to know what type of material your tank is constructed of, to obtain the correct adhesive.

Devcon has a series of plastic adhesives. One epoxy called "Plastic Welder" is compatible with many types of plastics. Loctite has an epoxy called "Plastic Bonder" that also works on some types of plastics. Lowes and Home Depot don't carry many of the available varieties from each of these manufacturers. I've found a well equipped hardware store usually has a better selection.

Again, if your tank is polyethylene, you will find these glues will not be effective for repairs.

You can buy a new tank for $100 depending on the size and capacity.

http://www.pplmotorhomes.com/parts/rv-toilets-tanks/rv-holding-tanks.htm

If you start spending $20 here and $20 there on products that don't work, It doesn't take long and you could have paid for a new tank.

thanks very much, i am on my way into town and will try again to find somthing. i am about 4 hours from the nearest rv or horse trailer dealer, thats why i wanted to try to repair myself first. it looks like when i took it in last fall to have the rv dealer winterize it, they forgot to add the antifreeze to the holding tank. would make perfect sense, as it was fine when i took it in, and just a few days ago went to dewinterize it. so, i will stay away from them, try to do it mysef come winter.