Two months ago I had a PSS shaft seal fitted. Checking it yesterday I saw a white crust had
formed on the carbon block where it mates with the stainless steel block. I didn't look to see
if the face was clean but there is no trace of any water leak.
Is this crust normal ?. Do I need to clean it off ? Is it anything for me to worry about ?.
Advice please.
I got the same crust on my PSS, I think its just salt and calcium, I cleaned it off the seal when I had the thing apart and I now see it has returned.
When I cleaned it off it was defiantly foreign and nothing to do with the seal. I too have no leaks from the seal so it must be just secreting from the film of water that lubricates the seal face.
I wouldn't worry about it,,, just carefully chip it off and give it a wipe
Select to expand quotesamsturdy said..
Two months ago I had a PSS shaft seal fitted. Checking it yesterday I saw a white crust had
formed on the carbon block where it mates with the stainless steel block. I didn't look to see
if the face was clean but there is no trace of any water leak.
Is this crust normal ?. Do I need to clean it off ? Is it anything for me to worry about ?.
Advice please.
Possibly salt, break a piece off and place on tongue to taste it.
It's actually from electrolysis!!
Don't ask me how or why I just have spoken to an expert and that what he said!!!
Thanks guys....Electrolysis... really. Well I know salt water can be one half of a battery so perhaps
it reacts with the steel and produces the crust that stick to the carbon. The people who produce the
product must know it happens but there's no mention of it in the fitting instructions. Hmmmmm.
I wonder if there's any chance of it affecting the prop shaft.
Carbon material is semi conductive, and it will form an electrolytic cell with metal. For example, carbon & ali composite in a very wet area is generally a no no.
Electrolytic damage to a timber hull boat can become a big issue, I turned down a boat in Victoria because it was going to cost approx $20k to fix the damage!
One of the best articles I have read on the subject can be found here waitematawoodys.com/2015/05/15/electrochemical-damage-to-wood-the-marine-version-of-leaky-homes/
It may be worth thinking of taking sacrificial anodes off your boat - I plan to do this next time mine is out of the water.
Regards Neil
That's a good article. On my yacht I have one shaft anode. On my old fishing vessel, Oregon on hardwood frames I used one anode to connect bronze rudder to shaft/prop. Bronze keel cooling and all the skin fittings had nothing. Now 72 years old [I don't own her now] original fastenings still good. No anodes is better than too many.
Couple of weeks ago I was at the slips and there was a 27 foot fibreglass yacht on the slips. It had a lead keel and the owner was just tightening up the bolts as I arrived. He had attached a trawler anode 6 x 4 inches to the bottom of the keel at the trailing edge! Well over a metre from the prop which could have done with a shaft anode. I tried to explain what anodes are for but it was like pissing into the wind!
Have a look here, what these guys don't know about cathodic protection isn't worth knowing!!
www.marineprotectionsystems.com.au/products
Yes, thanks rumble. I just rang D H Porter about the crusty stuff ( I bought the seal from them ) the
guy I spoke to said he had no idea what it was, so he was no help. I'm glad I'm not the only one with
it (jolene). It would be handy if others who have it reported in so we can see if it's a wide spread
problem or if it's just affecting me and Jolene.
Why not try some basic chemistry. Does it dissolve in warm water? Yes, then it is some kind of salt. (Which could still be a corrosion product.)
Put a bit in a nice clear flame. Does it turn the flame a bright yellow? If yes then is is probably sodium, and so plain old salt. If not, what colour?
Write up your results, and someone here who did better at chemistry than I did, will probably tell us what it is.
