Question for Viv, corrosion.

[nimrod1230]

I have a stainless steel waterlock. All seems in very good condition and rhe welds are very good quality. I have two holes about 2.5mm diameter well away from any welding influence. Both appear to have grinding marks around them for no apparent reason. No fasteners or contact points inside or out. Any comment from an expert?

 

[Lucky Duck]

An image of Donald Trump on a water lock, beats the usual suspects on toast, vegetables, etc I suppose

 

[RichardS]

Surely that can't be corrosion? It looks as if something has been fixed to the waterlock and then removed, rather cack-handedly. :ambivalence:

Richard

 

[lpdsn]

An image of Donald Trump on a water lock, beats the usual suspects on toast, vegetables, etc I suppose

But wouldn't you need patches of rust to represent the hair?

 

[nimrod1230]

It certainly does look as you describe. Nothing attaches and in fact the surface was covered by 3mm solid rubber sheet. The holes are rough, Matt inner surface rather than drilled. Both show what appears to be the start of a crack, both running in the same direction. Enough salt water in the bilge to prompt the initial search and lead to this point.

 

[NormanS]

It's definitely stainless? The welds look more like alloy.

 

[Tranona]

I have a stainless steel waterlock. All seems in very good condition and rhe welds are very good quality. I have two holes about 2.5mm diameter well away from any welding influence. Both appear to have grinding marks around them for no apparent reason. No fasteners or contact points inside or out. Any comment from an expert?

If it was covered by rubber sheeting then it could possibly be crevice corrosion. The grinding marks suggest it was very thin where the holes are.

Either have a plate welded over the damaged area or replace the unit with a plastic or GRP one.

 

[PaulRainbow]

Surely that can't be corrosion? It looks as if something has been fixed to the waterlock and then removed, rather cack-handedly. :ambivalence:

Richard

I agree, those holes have been drilled, IMO. Looks like it had a bracket that was badly removed and the aforementioned piece of rubber stuck on the seal it all up. Welding a plate on would be a reasonable answer.

 

[sarabande]

Looks as if the drilling has been done at an angle, with the chuck abrading the steel wall.

 

[vyv_cox]

They look like drilled countersunk holes to me, with grinding marks made during removal or possibly during the drilling. It is possible that some minor corrosion has taken place at the hole but the major damage is mechanical.

Vyv