Stainless Steel Corrosion hole repairs.

[paulcierra26]

I have a set of Stainless Steel "Duoprops that I aquired for my Volvo Penta DP-S Leg.
The props do not have any collision damage but one prop has a salt water corrosion hole about the size of the end of a pencil and the other prop has a corroded section on one blade about the size of a dime with a couple pin holes that go right thru the dime sized area.
Can these props be repaired?
Other than the couple of corrosion holes the rest of the props / blades look fine, at least to my untrained eye.
Is this kind of damage normal ?
I wonder why 99% of the rest of the prop surface area looks near new but yet still succombed to small very specific damage to the areas as described above.

 

[Bondo]

Re: Stainless Steel Corrosion hole repairs.

Can these props be repaired?

Ayuh,...

Only a qualified Prop Shop can answer that question,...

I would Think they could weld them up,...
But the guy with the props In Hand, will know for Sure...

 

[Frank Acampora]

Re: Stainless Steel Corrosion hole repairs.

Contrary to what most people think, stainless is not impervious to salt water corrosion. There are various degrees of resistance to corrosion depending upon alloy used to cast the prop.

I have a couple of props with pitting and have been advised by a prop shop that it is not possible to fill them; the weld will pop right out again. I did not believe them and asked a welder I know who is top at his craft. He agreed with the prop shop.

As far as your props, there may have been a weak spot where the alloy was not mixed well and corrosion started there. It is also possible that something was stuck to those areas and accelerated the corrosion there.

 

[luv2b0at]

Re: Stainless Steel Corrosion hole repairs.

Did you buy the props new. If not, they could have been welded before and the area popped out on you.

There is another theory that as the prop is used, there are small areas on the prop where the water is vaporized. As the vapor is created and returns to liquid, ultrasonic frequencies are emitted.

Here is a quote from a web site on the subject:

"The chemical applications of ultrasound, "sonochemistry", has become an exciting new field of research during the past decade. The history of sonochemistry, however, begins in the late 1800s. During field tests of the first high-speed torpedo boats in 1894, Sir John I. Thornycroft and Sydney W. Barnaby discovered severe vibrations from and rapid erosion of the ship's propeller. They observed the formation of large bubbles (or cavities) formed on the spinning propeller and postulated that the formation and collapse of these bubbles were the source of their problems."

Here is the web site:

http://www.scs.uiuc.edu/suslick/britannica.html

i don;t know where or why I heard about this before, but it stuck and I have always remembered it.

Hope this helps.