Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 02-07-2014, 11:06   #1
Registered User
 
rognvald's Avatar

Join Date: Jan 2011
Location: Summer: In the land of Wooly Mammoths
Boat: Pearson 34-II
Posts: 2,252
Images: 2
JB Marine Weld and Crevice Corrosion

For any "Metal Junkies" out there . . . do you think JB Marine Weld will seal very minor crevice corrosion on a stainless shaft after it has been treated with a metal rust remover to neutralize the rust? Is it even necessary? Will it hold up in a marine environment? Any comments will be appreciated.
__________________

__________________
"And those who were seen dancing were thought to be insane by those who could not hear the music."
Friedrich Nietzsche, Thus Spake Zarathrustra
rognvald is offline   Reply With Quote
Old 02-07-2014, 11:20   #2
Senior Cruiser
 
skipmac's Avatar

Cruisers Forum Supporter

Join Date: Oct 2007
Location: 29 49.16 N 82 25.82 W
Boat: Pearson 422
Posts: 12,373
Re: JB Marine Weld and Crevice Corrosion

Is the corroded area under the packing in the stuffing box? If yes, then I would think the friction would wear the JB Weld and not the shaft.

If the area is in an open part of the shaft then I don't see any reason not to give it a try.

By the way, JB Weld Marine grade? Have not seen that. Is it any different than plain old JB Weld (other than charging more to say marine on the tube)?
__________________

__________________
The water is always bluer on the other side of the ocean.
skipmac is offline   Reply With Quote
Old 02-07-2014, 11:48   #3
Registered User
 
rognvald's Avatar

Join Date: Jan 2011
Location: Summer: In the land of Wooly Mammoths
Boat: Pearson 34-II
Posts: 2,252
Images: 2
Re: JB Marine Weld and Crevice Corrosion

Quote:
Originally Posted by skipmac View Post
Is the corroded area under the packing in the stuffing box? If yes, then I would think the friction would wear the JB Weld and not the shaft.

If the area is in an open part of the shaft then I don't see any reason not to give it a try.

By the way, JB Weld Marine grade? Have not seen that. Is it any different than plain old JB Weld (other than charging more to say marine on the tube)?

Skipmac,
It is at the juncture of the top of the rudder and the rudder shaft where the shaft enters the rudder. Here's the info on Marine Weld.
www.jbweld.com/product/j-b-marineweld
__________________
"And those who were seen dancing were thought to be insane by those who could not hear the music."
Friedrich Nietzsche, Thus Spake Zarathrustra
rognvald is offline   Reply With Quote
Old 02-07-2014, 12:02   #4
Senior Cruiser
 
skipmac's Avatar

Cruisers Forum Supporter

Join Date: Oct 2007
Location: 29 49.16 N 82 25.82 W
Boat: Pearson 422
Posts: 12,373
Re: JB Marine Weld and Crevice Corrosion

OK, rudder shaft. I was thinking prop shaft although a rudder post can also have a stuffing box.

So the corrosion was right where the shaft exits the rudder itself as in the part of the shaft that is normally exposed to the water?

What about down into the rudder as well? Did you dig out a little to see if the corrosion penetrated beyond the exposed, visible part of the shaft?

My understanding of crevice corrosion is that it occurs on SS that is enclosed in a wet environment where the water is stagnant and becomes oxygen depleted. SS exposed to open water I would not expect to show true crevice corrosion so I would question what caused the corrosion and if it will continue.

Either way, it sounds like it's not a wear area so answers that concern. My only question is whether or not the JB weld will absorb any moisture or allow moisture to seep under the margins of the repair and stay damp against the underlying SS shaft. That would just exacerbate the problem. Why not just leave it as is, exposed so you can keep an eye on it?
__________________
The water is always bluer on the other side of the ocean.
skipmac is offline   Reply With Quote
Old 02-07-2014, 17:55   #5
Guy
Registered User

Join Date: Feb 2013
Location: So. Oregon, USA
Boat: Seafarer36c
Posts: 4,308
Re: JB Marine Weld and Crevice Corrosion

I have a similar problem but it's pitting not crevice corrosion (I hope.) I have tried JB weld, 4200, 5200 and epoxy and filler. At every haul out they have all been leaking around the shaft. I must not be cleaning the shaft well enough.
__________________
Guy is offline   Reply With Quote
Old 02-07-2014, 18:27   #6
Marine Service Provider
 
boatpoker's Avatar

Join Date: Nov 2008
Location: Toronto, Ontario or Bahamas
Boat: Benford 38 Fantail Cruiser
Posts: 2,593
Re: JB Marine Weld and Crevice Corrosion

JB Weld is great stuff, it does not however, halt corrosion in stainless steel.
The black and white photo below is an x-ray of a stainless steel shaft with one very small visible pit. The other photo is a broken ss shaft with microscopic pits on the surface.
Attached Thumbnails
Click image for larger version

Name:	x ray.jpg
Views:	142
Size:	24.4 KB
ID:	84336  
Attached Images
 
__________________
That hysterical laughter you hear as you sail a way in your "new" boat ..... is the seller.
boatpoker is offline   Reply With Quote
Old 02-07-2014, 18:33   #7
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,342
Re: JB Marine Weld and Crevice Corrosion

I cant zoom the image, but that second pic looks like a very suspect type of break. Almost looks like it was defective to start with. Too much cold drawing?
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is offline   Reply With Quote
Old 02-07-2014, 18:38   #8
Marine Service Provider
 
boatpoker's Avatar

Join Date: Nov 2008
Location: Toronto, Ontario or Bahamas
Boat: Benford 38 Fantail Cruiser
Posts: 2,593
Re: JB Marine Weld and Crevice Corrosion

Quote:
Originally Posted by Cheechako View Post
I cant zoom the image, but that second pic looks like a very suspect type of break. Almost looks like it was defective to start with. Too much cold drawing?
Wish I had a higher resolution shot of that one but it was taken years ago on a Sony Mavica 1.6 megapixel camera. Lab tests gave no indication of manufacturing flaws ...... strictly corrosion. This shaft was on a boat that had not moved in about ten years, the stagnant water sitting in the cutless bearing was the culprit.
__________________
That hysterical laughter you hear as you sail a way in your "new" boat ..... is the seller.
boatpoker is offline   Reply With Quote
Old 02-07-2014, 20:07   #9
Senior Cruiser
 
skipmac's Avatar

Cruisers Forum Supporter

Join Date: Oct 2007
Location: 29 49.16 N 82 25.82 W
Boat: Pearson 422
Posts: 12,373
Re: JB Marine Weld and Crevice Corrosion

Quote:
Originally Posted by boatpoker View Post
Wish I had a higher resolution shot of that one but it was taken years ago on a Sony Mavica 1.6 megapixel camera. Lab tests gave no indication of manufacturing flaws ...... strictly corrosion. This shaft was on a boat that had not moved in about ten years, the stagnant water sitting in the cutless bearing was the culprit.
Do you know the scale of the black and white photo?
__________________
The water is always bluer on the other side of the ocean.
skipmac is offline   Reply With Quote
Old 02-07-2014, 20:49   #10
Marine Service Provider
 
boatpoker's Avatar

Join Date: Nov 2008
Location: Toronto, Ontario or Bahamas
Boat: Benford 38 Fantail Cruiser
Posts: 2,593
Re: JB Marine Weld and Crevice Corrosion

Quote:
Originally Posted by skipmac View Post
Do you know the scale of the black and white photo?
Don't know the scale but I could barely fit a pin head in the pit.
__________________
That hysterical laughter you hear as you sail a way in your "new" boat ..... is the seller.
boatpoker is offline   Reply With Quote
Old 03-07-2014, 16:30   #11
Marine Service Provider
 
OceanSeaSpray's Avatar

Join Date: Aug 2013
Location: New Zealand
Boat: Custom 13m aluminium sloop
Posts: 414
Re: JB Marine Weld and Crevice Corrosion

Cleaning out the pits, using a drill bit if needed, and filling with high-strength epoxy filler, is normally a successful way of dealing with pitting/crevice corrosion (same mechanism and process), but on a stainless stock it leaves open the question of why it is pitting. This is not really a location with stagnant water anyway.

In this sense, it is unlikely to solve the actual problem. Here are a couple of questions I would try answering first:

- What is the grade of the metal in the rudder stock?
- Is it solid or hollow?

If I got the wrong answer to either of those, I would think about building a new rudder on a new stock.

I remember a yacht arriving in the Marquesas many years ago with no rudder (and a piece of floorboard at the end of the spinnaker pole hanging off the stern): the rudder stock was a heavy wall stainless pipe pitted all around at the insertion point in the fiberglass foil.

If you decide to patch up the corroded area, you need to go back to bright metal and then passivate the surface using pickling paste (not some hardware store DIY rustkill stuff). Get some from a workshop and be careful, it is highly corrosive.
__________________
"The case for elimination: the only equipment that never needs maintenance and never breaks down is the one you don't have on board."
OceanSeaSpray is offline   Reply With Quote
Old 03-07-2014, 17:17   #12
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,342
Re: JB Marine Weld and Crevice Corrosion

The problem with corrosion is you don't know how far the damage has gone. The pits may be from end of a micro crack. They may not also.
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is offline   Reply With Quote
Old 03-07-2014, 19:17   #13
Guy
Registered User

Join Date: Feb 2013
Location: So. Oregon, USA
Boat: Seafarer36c
Posts: 4,308
Re: JB Marine Weld and Crevice Corrosion

You bet and there are way more pits than cracks. If every pit had a crack there would be no ships, bridges, airplanes or spaceships.
__________________
Guy is offline   Reply With Quote
Old 05-07-2014, 00:07   #14
Registered User

Join Date: Oct 2013
Location: Vancouver Canada
Boat: Sutter England Carter 1 ton,37 ft
Posts: 12
Re: JB Marine Weld and Crevice Corrosion

I once had a neighbor who forgot to winterize His 4 cylinder engine . In the spring the-expanding ice had cracked his block. He cleaned and ground the crack and then used j b weld on it. It was cast metal. I thought no way--this will never hold as it was a large crack. He used the boat every summer for 4 years with no issues..that made a believer out of me





Sent from my iPad using Cruisers Sailing Forum
__________________
Cephious1 is offline   Reply With Quote
Old 05-07-2014, 10:03   #15
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,342
Re: JB Marine Weld and Crevice Corrosion

Yeah the stuff is pretty good sometimes. The custom Aluminum triple sheave on a watermaker /gen set I built cracked on the end sheave in the Bahamas. I JB welded it and it lasted until I returned to the States a month or so.
__________________

__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is offline   Reply With Quote
Reply

Tags
corrosion, marine

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Rudder Stock Crevice Corrosion Cruisin Cat Construction, Maintenance & Refit 15 29-04-2013 17:57
Crevice Corrosion On Rudder Stock stevensuf Construction, Maintenance & Refit 4 19-10-2012 13:07
Crevice Corrosion - Is My Rudder Toast ? funjohnson Construction, Maintenance & Refit 41 14-11-2011 22:14
Spreader Weld lockie Deck hardware: Rigging, Sails & Hoisting 3 14-05-2010 18:38
Crevice Corrosion Triton318 Construction, Maintenance & Refit 6 05-10-2008 14:37



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 02:14.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.