Holding tank replacement for a Hunter 280

[Peggie Hall HeadMistress]

You might try Dura Cast in Florida. They were the OEM for the plastic holding tank on my 1997 Hunter 310

You need to know that the DuraCast (aka DuraWeld) standard wall thickness--which was also Hunter's OEM wall thickness--is only .25", which isn't strong enough to support the 8.333 lbs/gal. weight of water and sewage in a tank larger than about 10-12 gallons without being supported on all vertical sides. They will make 3/8" tanks, but for a considerable upcharge.

One of main reasons I recommend Ronco is their 3/8" standard wall thickness that gradually increases for tanks over 40 gallons.

----Peggie

 

[Tim22]

One factor to consider about tanks -- a rotomolded tank should last for the lifetime of the boat, or yours....
Unless you physically break a rotomolded tank (with a large hammer?), it should not need replacement, and I would be hesitant to go back to the OEM vendor.
BTW, looking at the site for the Florida company, it appears that they are welding up their tanks. This can work fine, but the technique is tricky, and it's easy to get a poor-penetration weld. I have one welded custom plastic tank and it's working fine, but the guy that did the work was very skilled. (It was a custom shape not in the Ronco catalog, and having them make a steel mold was more $ than my budget allowed.)

Just to set the record straight, my tank broke at one of the connection fittings when I was trying to re plumb it. Not the fault of the tank, just an over zealous owner. Also, the original tank and the replacement were both rotomolded. No welding. I did order a thicker version for the replacement.

Tim

 

[Peggie Hall HeadMistress]

Y'll might enjoy a brief intro to PE (polyethylene) tank mfring:

Actually there is some welding in a rotomolded tank: the female threaded tank fittings are spinwelded into the tank. Spinwelding is a type of heat welding in which a special tool is used to simultaneously melt new PE and the edges of the hole so that they run together to form a single mass that's often a bit messy, misleading inexperienced owners to mistake it for some kind of sealant.

Those female threaded fittings and the male thread-barb hose fittings are NPT ("national pipe thread") standard, which is very slightly tapered--too slightly in such a short amount of threads to see the taper with the naked eye but tapered enough that over-tightening the thread-barb male fitting will cause the female threaded fitting to crack...not always immediately...sometimes it doesn't happen until there's a change in weather/temperature that causes a part to expand or contract...which is why you should only tighten the hose fitting NO MORE THAN a quarter turn past hand tight..just hand tight if you're a gorilla. Never use any sealant on the threads, only a generous amount of Teflon tape on the male fitting threads.

--Peggie

 

[Alan Gomes]

Actually there is some welding in a rotomolded tank: the female threaded tank fittings are spinwelded into the tank. Spinwelding is a type of heat welding in which a special tool is used to simultaneously melt new PE and the edges of the hole so that they run together to form a single mass that's often a bit messy, misleading inexperienced owners to mistake it for some kind of sealant.

I picked up a tank from Ronco once (they are just down the freeway from me) and watched them install the spinwelded fittings while I waited. It was really cool to see how they did that.