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Re: [PSUBS-MAILIST] Hot-galvanize stainless steel ?



Alec - during diving in the baltic I found the wreck of a 
modern sailboat maybe just 2 years underwater. 
I salvage a rigging terminal made from unpainted stainless steel. 
It has very bad big corrosion holes in many parts.. 

Is there a material I can put between the both - key and hole 
which is : 
- not metal 
- can be loaded with the weight pressure of the keel 
  (load area is 3600 mm2 with a load of 3 N/mm2) 
- is just 1-2 mm in tickness ? 

see you - Carsten

Alec Smyth schrieb:
> 
> Carsten, maybe I'm misunderstanding it, but as I understand your description
> you would have:
> 
> - A stainless shaft (or "key")
> - A stainless insert for it welded into a dropweight of plain steel
> 
> If you galvanize the drop weight (with the insert already welded of course)
> then the key and the key-hole would be of different metals so the corrosion
> problem would be worse than if they were both just SS. Wouldn't it be enough
> to just paint the drop weight like the rest of the sub for corrosion
> protection purposes, but leave the key-hole unpainted? If you wanted to get
> really fancy, you could sleeve the shaft in plastic like nylon or teflon, to
> prevent it from sticking after a year in the water.
> 
> rgds,
> 
> - Alec
> 
> -----Original Message-----
> From: MerlinSub@t-online.de [mailto:MerlinSub@t-online.de]
> Sent: Thursday, January 24, 2002 11:49 AM
> To: personal_submersibles@psubs.org
> Subject: Re: [PSUBS-MAILIST] Hot-galvanize stainless steel ?
> 
> "Dan H." schrieb:
> >
> > Carsten,
> >
> > Why not just weld in a stainless steel plate with your key way already
> > in it into a hole cut in your steel weights.  Instead of cutting out the
> > key in the actual steel weight, weld in a piece of stainless for the key
> > to fit into.
> 
> That it exact was I want to do. Maybe my description was a little short.
> 
> > Even if you had the whole thing galvanized and it didn't
> > take well to the stainless it wouldn't matter.  Actually, the part of
> > the key way in contact with the key will probably wear through the
> > galvanize in time anyway just from rocking back and forth in use, won't
> > it?
> 
> That is exact the question - would the galvanize hold on the stainless
> - or not ? I think that if the zinc gives way from the key-hole - we
> have a direkt contact from two parts of Stainless steel with a very
> little
> gap filled with saltwater between them - all the time in seawater -
> maybe
> the hole year. That should generate maybe a corrosion problem - and if
> one of the key-hole surface has to much structure on it - the key will
> not turn.
> 
> Maybe it would be better to make the key-hole-plate  from normal
> carbon steel. I am not affraid that the zinc gives way during
> "Using the key". If I use it - the drop weights gives way and the
> sub is not longer able to dive - so the weight will be lost and will not
> repaint..
> 
> >
> > Just a question; why didn't you use lead for your drop weight?  There's
> > so much more weight for the area it takes up.  A ton of old tire weights
> > doesn't make that big of a pile.
> >
> Maybe I will do it - a drop weight build from 1/3 inch strong steel
> plates
> as a box - and than filled with lead. It will be depents on the final
> weight calclulation - some month before CSSX contact the water in our
> river.
> 
> Carsten
> 
> > Dan H.
> >
> > Carsten Standfuß wrote:
> >
> > > Hi submadmans and ironheads,
> > >
> > > One question about metalurgy :
> > >
> > > Is it possible to Hot-galvanize stainless steel ?
> > >
> > > I want to build the drop-weights from normal mild
> > > and cheap steel and hot-galvanize it.
> > > The release-key will be made from stainless steel (SS).
> > >
> > > For the reason that the welded key-hole inside the
> > > dropweight can be made easy from the same plate as
> > > the key and with the same waterjet cut - I ask this
> > > unuseual question.
> > >
> > > drawing without scale : (and below 40 KB :-) )
> > >
> > > I = Stainless steel release key
> > > O = Stainless s. hot galv.? key hole
> > > = = mild steel hot galv.drop weight
> > >
> > > _____________________________________
> > >
> > >                  IIIIIIIturn90°
> > >                  I
> > >     =========    I    ========
> > >    ==========OOO I OOO==========
> > >   ===========  IIIII  ===========
> > >
> > > _________________________CS-1/2002___
> > >
> > > And please - I know that a full SS drop weight will fit
> > > the problem.. .. but I have three weights of 1,3 ts -
> > > means it generate another one..
> > >
> > > regards - Carsten