Holding tank/corrosive contents

[Bob L]

I went to the local metal scrapyard for the first time today - I don't know how to explain it - I thought the stories of mountains of stainless steel and junk that could be bought by the pound were urban legends... but they were true... oh, the sight of it... can't type... all verklempt now... need a moment...

OK. I bought a stainless steel cylindrical tank to use for my unconventional holding tank, and a 1 1/2" handicap toilet rail, the curved, flanged ends of which will be converted into intake/outlet fittings. However, I was so obsessed with the idea of a non-permeable holding tank, I didn't think of an obvious problem - the contents corroding the tank!

I'm not talking about my contribution, but the saltwater used to flush. Will the salty contents corrode the stainless steel? If so, should I install a zinc? (Or just take zinc supplements?)

Or should I scrap this idea (sorry) and use plastic instead?

Thanks in advance for the comments.

Bob

[Curmudgeon]

The problem isn't so much saltwater - it's the liquid waste - urine is extremely corrosive. My boat had an aluminum holding tank that was riddled with pinholes from interior corrosion. Peggy Hall is the rec.boats.building guru for on-board sanitation and in the article http://www.amazing.com/cruising/fvf.html she stresses that "no metal of any kind should ever (be) used to hold sewage.

[Tim]

I agree. Holding tanks are made of plastic for a reason. You are asking for trouble if you use any sort of metal in this application.

As to overall head/holding tank information, I'll defer to the "head mistress", who has put way more thought into this (ahem) crappy situation than I ever care to.

The Head Mistress Forum

[Bob L]

Rats. No loss though. The tank I bought looks like a really tall fire extinguisher. I think I can turn it into a fireplace. Or a grill. Otherwise I'm out $10. Thanks!