Re: SM 2000 head backflow and holding tank leak -second attempt
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Thanks James. This is good information.
Epoxying in a fiberglass tube riser will be my next/third attempt… if the sanitary hose solution doesn’t hold up.
From: main@AmelYachtOwners.groups.io <main@AmelYachtOwners.groups.io> On Behalf Of James Alton via groups.io
Sent: Tuesday, June 23, 2020 2:50 PM
Subject: Re: [AmelYachtOwners] SM 2000 head backflow and holding tank leak -second attempt
I have built a few custom holding tank systems for boats (Not yet on an Amel) that have so far proven reliable. I think that the most important step if you want to minimize problems is to eliminate ALL metal in the system that is exposed to the corrosive contents. Polyester/glass will work, Epoxy/Glass is better IMO because Epoxy does a better job to contain odours and is not as prone to water absorption. I also apply a barrier coating on the inside of the tank prior to closing it. It may not be essential to add a barrier coating since I build the tanks I have built used epoxy resin but I tend to go with belts and suspenders on these kinds of projects! The suggestion of using hard PVC pipe to reduce odours is a good one and far superior to using hose, even the best sanitation hose. If you want to take it a step further you can use fibreglass pipe that can be fibreglassed right to the tank, eliminating a lot of the leak prone joints. You can buy polyester/fiberglass exhaust pipe in various sizes and a few shapes. The pipe is a little thin I think.. While you can bond some materials such as PVC to a fibreglass tank, the bond is quite poor structurally as compared to properly joining two compatible pcs. of fibreglass. It’s not hard to cut a fibreglass pipe if needed for service in the future and either glass it back together with wraps of glass tape/epoxy or in a pinch you can put in a length of hose until more permanent repairs can be made. While time consuming compared to the normal methods of running hose, it is possible to make custom epoxy fibreglass piping to the exact non clogging (gentle curves) shapes desired and to make them strong which is my preferred method. I like to make the pipe walls about as thick as the tank and glass the joints together. All of the tank input pipes that I have installed come in at the very top of the tank with no downward extension. I am not sure why the pipe apparently extended to the bottom of your tank which as you suggest would appear to create a siphon effect, keeping pressure on your back flow devices. Sorry for the problems, best of luck in finding a solution that works for you.