Holy Breaking Hose Clamps, Batman

[bobk]

When I requested a mechanic referral a week or so ago due to a coolant leak (port 6V92TA), we found a a clamp on a coolant pipe had broken but stayed in place and looked fine. Pressure testing reproduced the leak and the hose clamp was changed. End of story? Not!

The next day, 70 miles further south, another one broke, also on the coolant side. So I started changing clamps as PM. By the time I was done, I found one more broken clamp on the starboard side engine and one of the double clamps on the washing machine discharge.

Why so many all at once? These were a mixture of small cheap clamps and the more expensive types with indented rather than cut through threads on the band. Some were much newer than others. What they all had in common was exposure to muriatic acid fumes when a mechanic cleaned one of the cooling systems using the Genesis method. I requested he use non-volatile phosphoric acid, but what does a chemist know? (Karl, don't bite my head off.... I like your method but I never liked having such a volatile, corrosive acid in the ER.)

Anyway, this is for info only for our friends here. Meanwhile, I need to buy some larger clamps to finish the project after we reach Port St. Lucie.

Bobk
Chateau de Mer
lying Isle of Palms

 

[MikeP]

Same thing happens in areas exposed to chlorine fumes from tablets like calcium hypo used in systems such as the galley maid waste treatment system or similar units. The clamps in my starboard eng room and under the cabinet in the master SR where the canisters holding the tabs are located, have to be replaced every couple of years or they will fail. In the case of the master SR, that includes the muffler clamps on the starboard side. They initially turn rusty and if left alone, will snap at the point where the screw tightens the band.

I wouldn't think one exposure to muriatic fumes for a brief period would do anything at all but maybe so - is it possible the mech could have spilled the solution on the clamps?

 

[Genesis]

Bob, I would never use muriatic acid in a confined space for "in-situ" cleaning; phosphoric yes, but not muriatic.

With that said the most-likely cause of the failures is crevice corrosion and unrelated.

 

[bobk]

Karl,

Sorry, I didn't re-read your method but thought/recalled that you used muriatic in the proceedure. We certainly are in agreement. Unfortunately I tossed the broken clamps and never thought to look carefully at the breaks. They all had a bit of rust on them and the breaks were at the perforations in the band.

Mike, no way these were splashed with acid unless the mechanic sprayed the ER. Not likely. But right after the cleaning was done, there were signs of slight corrosion. That was five years ago.

Bobk

 

[MikeP]

Just ran across this info which I had never known about prior to my personal experience with the chlorine tabs/hose clamps. Was doing some searching based on this thread.


"Noteworthy
Chlorine (like that in salt) can eat thru and destroy the thin protective layer of passivation that protects stainless steel from corrosion. If chlorine gets on your stainless, clean it with fresh water immediately. Chlorine is to stainless, like cancer is to the human body.

Consumer Alert!

Never use muriatic acid to clean tile or stone grout around a stainless steel refrigerator or appliance. The fumes are enough to permanently discolor the stainless. Always remember - it's stain-less - not stain-proof."

The above is from this site:
http://www.estainlesssteel.com

It appears to me - I'm no chemist - that both compounds can attack the protective layer of SS.

 

[Tinker]

There is a place in fort pierce called turner industrial suply. On orange ave they should have everything you need and at reasonable prices. There is also a shop next door that can make rudders trim tabs etc. maybey try the tstyle clamps or the constant torque ones. My uncle was sending pictures of the piers on north hutchinson island under water at the same time we we under in va beach. Giant storm.

 

[jim rosenthal]

Useful to know this stuff, and thanks. I think the OEM clamps on most marine diesels are much better than what we commonly buy, unless we shop very carefully. I have used and recommended AWAB clamps in the past with good results. They cost more, but seem worth it. I also use T-bolt clamps, but you have to watch not making them too tight- they can crush what they are put onto.

 

[rsmith]

Useful to know this stuff, and thanks. I think the OEM clamps on most marine diesels are much better than what we commonly buy, unless we shop very carefully. I have used and recommended AWAB clamps in the past with good results. They cost more, but seem worth it. I also use T-bolt clamps, but you have to watch not making them too tight- they can crush what they are put onto.

AWABS should only be used on soft silicone hose. They are designed to not damage the soft hose. they do NOT bite hard enough into regular hose to keep it from slipping off fittings. Ideal has 2 different quality clamps make sure you use the 316. Regardless hoses and clamps should be replaced every 5-7 years.

 

[bobk]

I'm back in Port St Lucie and did a count of the hose clamps (not including the rebuilt starboard engine as these are all new AWAB). Would you believe more than 110 clamps????

I followed up with Turner and they gave me a fair price, but the guy who runs Designated Engineer in Ft. Pierce is likely to be much better and offered to quote. Then the work begins. I can probably reach 50-60% of the clamps to replace them, but will need some one more limber than I am to get into the difficult places. I'm considering using a guy who works as a helper for one of the mechs here as he charges only $20/ hour vs $80-90 for mechs.

By the way, Turner said that AWABS should be used on reinforced hose. They are a quality hose clamp that ought to work fine on any hose, but may be over kill in some applications. So be it. I do not want another hose clamp failure. Four in one trip is enough!

Bobk

 

[magnawake]

Wow, Bob.. well glad yall made it there. I was thinking of changing all my hoses and clamps, just to be sure. That is before we go cruisin next summer. Till then I have to go back to work. Whew, the life of a contractor. Feast or famine.