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09-10-2009, 06:51
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#1
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Registered User
Join Date: May 2009
Posts: 41
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Monel vs Stainless
How can you tell the difference between monel and stainless, for example, when a seller tells you that the fuel tank is monel? What are the best materials for water and deisel tanks?
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09-10-2009, 07:11
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#2
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Registered User
Join Date: Aug 2009
Location: Sarasota, FL
Boat: All kinds of 'em, from 9' dinks to 100+' motoryachts, power or sail...
Posts: 89
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Good question on how to tell the difference. Not sure there...but I do know monel is supposed to be a superior alloy to stainless steel in terms of corrosion resistance etc. Very expensive stuff. Probably not something you're going to go buy these days for a fuel tank or whatever, but if it's there, and in decent shape, I'd leave it right where it is.
Rob
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USCG Lic. Capt. Rob Welling
Professional Delivery Captain
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09-10-2009, 07:58
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#3
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Registered User
Join Date: Jan 2009
Location: SW USA
Posts: 74
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Monel has a somewhat duller appearance as it has no chromium. It's a nickel-copper alloy. The K-500 version includes some titanium for strength. I had some valve stems made of K-500 monel for acidic salt water service (oilfield, produced water in a CO2 flood) where 316 SS was dying in 3-4 months. Last I knew, those valve stems had lasted 6 years.
If you attempt to polish a small section, it will be pretty obvious that it's not SS due to the dull appearance. It will look much more like nickel than like chrome. Monel is very, very corrosion resistant, but is typically much more expensive than even 316L stainless.
Monel is a superior fuel tank material, hard to imagine anything better. If you could afford it, it would probably be great for water tanks, too, but at the high end these are usually 316L stainless.
I am aware of only one US production boat manufacturer who has used it for fuel tanks - Hinckley - but there may be others.
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09-10-2009, 08:11
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#4
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Registered User
Join Date: Jul 2009
Boat: 48' 1963 S&S yawl
Posts: 851
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We have monel tanks. it's a dull grey and the fittings are (supposed to be) bronze rather than stainless or plastic. If exposed to spray, it may have some greenish flecks.
I can maybe take a pic this weekend.
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09-10-2009, 08:19
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#5
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Registered User
Join Date: May 2009
Posts: 41
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Thanks, that is what I needed. Asking because I might go look at a boat adv. in YW and didn't want to go in blind. After monel and 316 what is next best?
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09-10-2009, 08:39
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#6
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Registered User
Join Date: Jul 2009
Boat: 48' 1963 S&S yawl
Posts: 851
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Polypropylene or aluminum I'd guess for water. I don't like the idea of fibreglass tanks.
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09-10-2009, 08:51
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#7
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Registered User
Join Date: Aug 2006
Location: Skagit City, WA
Posts: 25,483
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I havent looked but I dont believe monel will normally be magnetic....? Stainless will often be magnetic... at least slightly... Monel is extremely good stuff but you dont see it much anymore, although I think it's still available readily for prop shafts.... you wont see any rust on monel.
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09-10-2009, 08:54
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#8
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Registered User
Join Date: Feb 2008
Location: Eastern Seaboard
Boat: Searunner 34 and Searunner Constant Camber 44
Posts: 949
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Quote:
Originally Posted by karlhead
Thanks, that is what I needed. Asking because I might go look at a boat adv. in YW and didn't want to go in blind. After monel and 316 what is next best?
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Ultra High Molecular Weight Poly Ethelene (UHMW, UHMWPE; UHMW-PE) comes to mind.
It's rated as food grade and is very chemically resistant
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Regards,
Maren
The sea is always beautiful, sometimes mysterious and, on occasions, frighteningly powerful.
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09-10-2009, 08:58
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#9
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Registered User
Join Date: Jul 2009
Boat: 48' 1963 S&S yawl
Posts: 851
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Quote:
Originally Posted by Cheechako
I havent looked but I dont believe monel will normally be magnetic....? Stainless will often be magnetic... at least slightly... Monel is extremely good stuff but you dont see it much anymore, although I think it's still available readily for prop shafts.... you wont see any rust on monel.
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Monel is non-magnetic. It can get a kind of dark green corrosion on it, but not significant (even after 45 years).
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09-10-2009, 09:09
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#10
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Registered User
Join Date: May 2009
Posts: 41
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Quote:
Originally Posted by Maren
Ultra High Molecular Weight Poly Ethelene (UHMW, UHMWPE; UHMW-PE) comes to mind.
It's rated as food grade and is very chemically resistant
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If I have to fabricate a tank will this stuff work? I mean that most tanks are shaped irregular so does this stuff come in sheets, rolls, etc.?
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09-10-2009, 11:04
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#11
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Registered User
Join Date: Aug 2006
Location: Skagit City, WA
Posts: 25,483
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If you can sketch it, try Tank Depot...
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09-10-2009, 11:36
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#12
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Registered User
Join Date: May 2009
Posts: 41
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Thanks. I'll file this site.
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09-10-2009, 14:12
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#13
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Registered User
Join Date: Feb 2008
Location: Eastern Seaboard
Boat: Searunner 34 and Searunner Constant Camber 44
Posts: 949
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Quote:
Originally Posted by karlhead
If I have to fabricate a tank will this stuff work? I mean that most tanks are shaped irregular so does this stuff come in sheets, rolls, etc.?
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It does come in sheets. Try garland manufacturing or any of number of others
Another alternative that comes to mind (for water and wastewater) since you mention the irregualar shape is a flexiable tank that hardens.
You put the flexible out tank in the space, inflate it and insert a UV bulb which hardens the tank. Then you put in the liner tank which is made up of food grade polythene.
Cheechako: I checked your link for any reference to UHMW with no results, were you speaking of something like plastic or ... something else?
__________________
Regards,
Maren
The sea is always beautiful, sometimes mysterious and, on occasions, frighteningly powerful.
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09-10-2009, 16:09
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#14
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Registered User
Join Date: Aug 2006
Location: Skagit City, WA
Posts: 25,483
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They made a great custom Plastic Blackwater tank for me. reasonable prices. Nice thick stuff like 3/8. Have to ask if they do diesel tanks though...
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09-10-2009, 16:15
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#15
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Registered User
Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 20,420
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Quote:
Originally Posted by S&S
Polypropylene or aluminum I'd guess for water. I don't like the idea of fibreglass tanks.
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Fiberglass tanks for water are great way to go - jellycoat inside. Gellycoat is inert to water and does not rust. But a GRP tank probably just possible in a new build.
The MONEL things we have here are - more goldish in colour than SS and (...) more expensive - how much would a tank be??? (A monel rivet is 200% the price of SS I guess (?)).
b.
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