Anchor metal appearance

[Roberto]

My anchor shank has recently taken this appearance, there is a visible line of different looking metal starting out of the hole, different to the touch too it is slightly rougher.
The galvanising has worn out in places, in the area taken by the picture too, the anchor has had a few hundred days underwater.

Just out of curiosity, does it represent anything in metal working? A weld ? Local heat treatment ? Locally worn galvanising due to local stress ?

ps (I am very, very happy with this anchor and have 0% need of changing it, so not looking for answers "this other brand is better built" etc etc)

 

[vyv_cox]

Looks very much like a weld to me. Try filing and abrading to a bright finish on the inner radius and macro-etch it, with HCl. Just brush a bit on and leave it until the surface dulls. A weld should then be pretty obvious as a separate structure from the rest.

HCl is not ideal but probably easiest for you to get hold of.

 

[Roberto]

thank you Vyv I was secretely hoping for you passing by

I do have HCl, I'll try that tomorrow and post a picture.
The shank is flat and looks very much like being cut from a sheet of thick metal plate. not sure why they would put a weld there (?).

I'll try and post a picture of the home made HCl etching

 

[MM5AHO]

And the reason it looks different is that galvanizing reacts differently with different chemistries if steel. Welds should be the same as parent metal normally, but often are not, so you get different thickness of galv. Galv lasts proportional to thickness, so a thicker or thinner area lasts longer or shorter. Looks like the weld had thinner galv just over the weld. Not uncommon.

 

[TradewindSailor]

If it is a weld, please name the maker as the shank should be one piece .... I would never trust my boat to such an anchor.

 

[NormanS]

I don't know what type of anchor that is, but it looks as if it's been shaped by cutting out a wedge, then being bent together, and welded.

 

[J Neeves]

As Geoff says the weld should be stronger than the components it joins, (the welds of your chain should be stronger than the wire from which it is made - and no-one worries about welded chain). Whereas, if it is a weld, it does seem a most unusual method of construction - cutting one steel plate must be easier than cutting 2 pieces, matching them and then welding them - but very strange things happen in the whacky world of anchors.

Maybe, Roberto, when you confirm your findings you can confirm whether you bought the product new, whether it was sold as the genuine article (and you had no thought that it might be a copy) and finally what type of anchor it is (someone will look through your posts and find out anyway!).

But I would be interested in anything Vyv might say about a '2 part' welded shank - realising of course the shank is welded to the fluke anyway (and fluke to shank welds are not renowned for failure - though fluke to shank welds tend to have more meat in them than this one does).

Jonathan

 

[cliff]

If it is a weld, please name the maker as the shank should be one piece .... I would never trust my boat to such an anchor.

Do you never get tired talking utter bollox? Firstly you do not know if the shank was designed as one piece or as a welded profile. Secondly a properly made weld can be, and normally is, stronger than the base metal. - you have a 70,000psi steel?, I will make the weld 80,000psi I am sure viv will come along again and confirm the strength of welds having carried out many 000's of tensile tests in his past. failure in weld but above min base material uts is acceptable though I would estimate I would see base material failures rather than weld metal (I too have carried out '000's of tensile tests in my day.
The biggest problem with welding is the equipment is so easy to get hold off and relatively cheap so we wind up with a load of folk who think they can weld just because they have a "welding machine" and can stick two pieces of metal together - we refer to them as "pontoon welders" - you know - Stick and Twist.
Back to the OP's question - it does look like a weld - either do as Vic has suggested or polish the surface with fine emery 'til smooth and bright then try etching the surface - 2% Nital is a good etchant if you can lay your hands on a small quantity of HNO3 and some Isopropyl Alcohol (one cc Nitric acid to 49ccs IPA - 10% is good for a rough etch - 1cc acid added slowly to 9ccs IPA.
I would think the manufacturer looked the nesting drawings and decided there was too much waste in cutting the shaped profile rather it was more economical to cut or shear the profile straight and then notch and weld - who knows what goes through manufacturers minds - I would not worry about it - think about all the welds in your anchor chain - every link is welded.

 

[J Neeves]

In defence of Tradwindsailor,

Unless Roberto has bought a very unusual, and little known, anchor then what he identifies has never been seen on a well known brand name anchor previously. One might thus assume that as all other shanks have been designed as one piece then this one should be one piece as well. Whereas welds are meant to be stronger than the metals being joined the very unusual practice of joining the 2 pieces of the shank with a weld might raise the very point you make - that anyone can buy a cheap welding machine today - and anyone willing to step outside the norm of shank production (of a one piece shank) might know nothing about welding either. So Tradewindsailor might be talking bollox - but I think he has a valid point and he is right to raise it.

However, just to contradict myself, Roberto does appear to have used his anchor fairly extensively without any problems which suggests maybe the welds are top notch - or maybe he was lucky (there are examples of anchors being used for weeks - without issue - and then inexplicably failing under quite benign conditions, maybe illustrating we cannot take short cuts in anchor design and production).

I'd still like a second opinion on shank welding and look forward to a more knowledgeable comment than anything I can make.

Even more interesting might be a comment from the manufacturer of that brand of anchor, though your comment Cliff that this was a cost effective way of using the steel has great merit (as the reason it was done). Whether the practice of a 2 piece shank has merit awaits that more knowledgeable post.

Jonathan

 

[vyv_cox]

A welded shank like that one is new to me but as Cliff says, no reason to doubt its integrity. Welding done properly is perfectly acceptable and is common on many components that are far more stressed than an anchor shank. Gas pipelines snaking across Europe, for example, with pressures of 400 bar inside them. Loss of a bit of galvanising is hardly cause for concern.

I would have suggested Nitric acid in ethanol (nital) but thought that obtaining it might be more problematical. Be aware that HCl will remove the galvanising pretty smartly so restrict it to the steel, I use a plasticine dam for this kind of thing.

 

[J Neeves]

Nital has been mentioned a couple of times. I tried to get some here and though I could buy litres of it (at some significant cost) I could not source 5ml. What sort of outlets/people would sell small lots in the UK. I wanted it to etch galvanising in polished sections.

Jonathan

 

[vyv_cox]

Surprisingly to me, Amazon sell nitric acid in 500 ml bottles for about £13. We always mixed our own 2% nital in ethanol but I assume that it would make little difference to use methylated spirits.

 

[Deleted member 36384]

It does not look like a weld to me, why does the feature not extend above the hole? Notice how the feature tapers from a width equal to the OD of the hole to something less towards the bottom. Is it held in place with a pin through the hole and the hole causes water to coalesce and thus more water runs down this area? The colour difference also extends along the base of the shank a bit. It looks like a rust stain.

 

[J Neeves]

BlowingOldBoots

You could be spoiling an excellent story! and be right.

Jonathan

 

[vyv_cox]

Second photo looks very weld-like to me, but you might be right. Etching it should tell.

 

[J Neeves]

Surprisingly to me, Amazon sell nitric acid in 500 ml bottles for about £13. We always mixed our own 2% nital in ethanol but I assume that it would make little difference to use methylated spirits.

It never crossed my mind that Amazon would sell Nitric (or any other acid) - so I did not check. I'll have a look.

Stg13, or its equivalent is not much, anyone need 495mls? Meths is a cheaper and more easily obtained option, ethanol is also available (fashionable heaters, for our bitter winters).

Many thanks

Jonathan

 

[Bloomy]

The anchor you are looking at is a Rocna. It has two aluminium ID plates, one either side. One is missing and one is covered with tape. Corrosion from the alloy ID plates bridges the sticky label that holds them on to the shank. This corrosion then spreads creating the white spotty appearance. The hole in the anchor shank will hold corrosion allowing it to weep out down both sides of the shank removing the galvanizing.
Regards
Bloomy

 

[Roberto]

Update

Thanks all for the replies.

I used a wire brush over the area on both sides of the shank, I put a few drops of HCl but could not see any effects, so I poured a bit more; the area did not look affected by the liquid, the acid was in an old bottle I gue"ss it may have lost some of its strength (?)

Anyway, this is one side of the original hole

this is the other side

The anchor shank has another hole, where oddily enough the "stain" appears one one side only

this is the same second hole, on the other side, no stain is apparent

When stowed on the bow roller, the anchor does not have a securing pin, the two holes are "empty".

The original question is more of a curiosity, weld or not weld with the experience I have had with this anchor I have no reason to change it

 

[cliff]

Surprisingly to me, Amazon sell nitric acid in 500 ml bottles for about £13. We always mixed our own 2% nital in ethanol but I assume that it would make little difference to use methylated spirits.

Be very careful using meths - it evaporated very quickly increasing the % concentration. Not so much a problem on the specimen but in the container it could be. IIRC around 25~30% the Nital solution becomes "unstable" Well it does when mixed using IPA and don't ask how I know!
Thanks for the tip for Nitric

 

[cliff]

Whether the practice of a 2 piece shank has merit awaits that more knowledgeable post.

Jonathan

Yep, I am only a Metallurgist with 35 years experience in fabrication / welding in the Oil, Gas and Power Generation industries so obviously don't have sufficient knowledge to comment.
As Viv has already pointed out "Welding done properly is perfectly acceptable and is common on many components that are far more stressed than an anchor shank." As Roberto has covered the manufacturer's plate we do not know who made it.