|Treatment of salt in the pores of cas...
Post Number: 1149
|Posted on Saturday, May 12, 2012 - 02:39 pm: ||
Posted for Dick Day
Treatment of salt in the pores of cast iron parts of marine engines.
By Richard A. Day Jr.
The restoration of antique Marine engines long exposed to salt water demands treatment of the residual salt in the pores of cast iron parts. Many restorable and rare antique salt water marine engines have been destroyed by well-meaning individuals and organizations by allowing them to dry out in storage or on exhibition. The cause is cast iron is porous and salt water penetrates deep into the surfaces. One only has to look at the surface cracks which look like freeze cracks to know the artifact is in serious trouble which will probably only get worse unless properly treated. As the rusting penetrates chunks of the surface iron slough off exposing further areas to further exposure of the salt in the iron. The most vulnerable areas of marine engines are the internal cooling water passages. They are also the area’s most difficult and critical to get access to for treatment. In many cases the internal damage is too great to correct as it is inaccessible. This means a replacement part must be found or recreated the latter being complicated and too often beyond reasonable investment.
It was common practice for old time watermen to save their nearly worn out cast iron cylinders, cylinder heads, exhaust, intake manifolds etc. by filling the water passages with used motor oil or placing those parts in containers full of used motor oil. This practice allowed quick restoration of a needed engine to operation while waiting for a replacement part to arrive from the maker which could be weeks or months. They knew letting air get to the salt would destroy any further use of the old part if it was left exposed to the air.
It should be noted that many antique marine engines were painted sometimes multiple times on their exposed surfaces so the salt penetration is often much less serious on those surfaces but it can be still present.
Having turned the rim on down deep salt pitted cast iron flywheels as much as 3/32” within 24 hours one can see the air interacting with the salt in the freshly exposed iron surfaces. Painting the surface seems to cure the problem but it doesn’t really solve the long term problem as the salt is still present under the paint. The currently known best permanent solution is raising the temperature of the cast iron to drive the salt out of the iron. An alternative solution which does have some complications if one wants to occasionally run the engine at shows is to fill the water jackets with undiluted automotive anti-freeze to keep the air away from the salt in the iron.
The “Oldest known” Palmer Model B is now owned by Ernie Darrow. email@example.com .
It was purchased from Palmer Bros. November 10th 1899 by Mr. Adams. Used in a small boat in ferry service from New Haven, Ct to East Haven, Ct
It was passed on to his son in law Charlie Avery of East Lyme, CT. He used it in various boats over the years in the Niantic, CT area. Ernie purchased it from Charlie in 1992. This engine is an example with reasonable care an engine used in salt or brackish water the water jacket should not easily rust out or crack. This engine spent all of its working life in salt water and the water jacket is clean and has no cracks or repairs today in 2012 at 113 years of age. The water jacket has been kept it full of diesel fuel for the 20 years that Ernie has owned it to keep air away from any salt in the pores of the cast iron water jacket.
Filling the cylinder water jacketed parts with used Motor oil or typical automotive Anti-Freeze also works very well. Anti-freeze is a lot easier to clean up from a leak than used motor oil. Diesel leaks can cause fire hazard problems. I have run into rusting problems with storing steel gears in Diesel. Not sure how cast iron responds to long term diesel exposure when compared to anti-freeze. Anti freeze works well in applications where the engine is to be run from time to time at shows.
Diesel or motor oil don’t mix with water and would be very difficult to deal with for engines used at shows.
For engines run at shows drain off the anti-freeze and run with fresh water in the system. After the show drain the fresh water and replace the anti-freeze with the same anti-freeze removed before the show. Use short lengths of 3/8’ dia. plastic tubing for filling the water jacketed parts from the lowest portions of the water jacketed parts. Tape the tubing to the side of the water jackets to act as a gauge in the event a leak develops. To save on the amount of anti-freeze required use small pieces of brass scrap shim stock to block off bronze water piping by simply loosening the flange cap screws and slipping the shim stock between the flange and the gasket to the cylinder wall.
With undiluted anti-freeze any small residual pockets of water left in the jacketed parts there is also no danger of freezing in storage during the winter.
Freezing is not the problem for long term storage!! Salt expansion from moisture in the air in the iron is the problem! In cast iron the way to remove the salt/rust from the water jacket is to slow heat/cool the item to a very high temperature to drive the salt out of the iron.
Some small cast iron items have been successfully dealt with by heating in a backyard barbeque. Larger items and rare items should be dealt with by professionals.
One only has to see on http://www.ghcoates.com/Barker.htm the remarkable work done by the George Coates group to understand just how badly salt deteriorated cast iron can be brought back from a seemingly total loss.
George Coates, GH Coates, LLC
120 H James Way, Elkton, MD 21921
It has been my experience this group is a rare find when it comes to antique cast iron restoration particularly salt water damaged engine water jacketed parts. They also manufacture parts for the Schebler Model D carburetor.
The following is a warning to those wanting to restore a salt water damaged item.
The typical automotive dip tank may remove oil and grease but I have seen no example where it could or has dealt effectively with salt in cast iron. In my opinion caustic soda or acid treatments do more damage than removing any salt from salt damaged cast iron.
Post Number: 124
|Posted on Sunday, May 13, 2012 - 11:12 am: ||
I used to have an MD17C in my sailboat. After using the engine in salt water I would flush it with freshwater and leave the freshwater in it until I next used it.
If the boat were not to be used for a month or so I would flush it with fresh then replace the fresh with anti-freeze.
Post Number: 1151
|Posted on Wednesday, September 19, 2012 - 07:07 pm: ||
A bump to move this timely write-up higher up the list. Fall is here in the northern hemisphere and it might be wise to review this again...