Re-galvanize anchor chain

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Explosions!

vyv_cox: The reason for explosions is NOT Lead. In fact I have never met a galvanized anchor with lead in it.

In the base of some anchors eg. CQRs there is a welded in void. This comes from welding the STEEL wedge shape into the gap between the blades. These voids must be drilled before putting in the bath. Afterwards a few drops of zinc and a blow torch sorts out the hole.

If you read the term and conditions, it is all there. The problem with Wedge is the terms and conditions are on the back of the bill. You do not get that until after the job is finished! They are not really set up for re-galvanizing which requires much longer in the cleaning baths.

Google "zincofuoco". www.zincofuoco.it. Ask for translated pages, and try to read the pre-conditions and descriptions of the process. All that information on the Wedge site would be a start.

The last time I had one galvanised I suggested that Wedge make a work sheet and user information online for anchors and chain. Then they would not mess up every time. CQRs should be drilled 1/2" from the ridge on either side through the blade material thickness into the void. They seem to pride themselves with quick turn around time, but actually we want quality and care. What is wrong with waiting a month instead of their current record of 3 days, including delivery!
 
halfway said:
vyv_cox: The reason for explosions is NOT Lead. In fact I have never met a galvanized anchor with lead in it.
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Sorry, you are incorrect and ill-informed. I saw the failed anchor, it clearly had a one-inch pour hole for lead, which was empty. I looked inside and it was obvious that it had contained lead, or some other low-melting metal. I picked it up and it weighed far less than it should have done.

Spade anchors have lead in their tips (although the manufacturers shyly call it 'ballast' rather than lead.) They come with a warning that the galvanizer should be informed if they are to be re-coated so that he can remove the lead first.

Older CQR anchors, Simpson Lawrence made, had lead in their tips.

Anderson anchors have lead in their tips.

Manson Ploughs (like the one I saw) have lead in their tips.

I believe that many others do too, although I have been unable to come up with names.
 
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Lead or not in the anchor, its not the lead that causes the explosion. In fact it used to be practice in the industry to add lead to the melt, to about 1% by weight.

Molten zinc is usually held at about 450 deg C. for galvanizing. Any cavity in a steel fabrication has a chance of trapping moisture inside. If the cavity is sealed with moisture inside, that water will boil rapidly, then turn to superheated steam, and build a pressure that the steelwork was not designed for. The result is an explosive rupture of the steel, mostly along the weld as that is the weaker point, and the ejection of the contents, but submerged in zinc.
The sudden release of the pressure means an expansion of volume of the superheated steam, but as this was under molten zinc, there results a massive eruption in the zinc, splashing molten metal upward.
If it were pure dry lead occupying the cavity, it would simply melt. Lead melts at about 328C. In molten zinc the lead (being about twice as dense) mostly sinks to the bottom of the tank of zinc, but some goes into solution in the zinc. If it melted still contained in the cavity, it would just stay there, and solidify as the anchor cools after galvanizing.

It doesn't take much longer to clean the steel for re-galvanizing an anchor that to clean for a newly fabricated anchor. The hydrochloric acid used to clean the steel dissolves the zinc of the old galv quite quickly (making zinc chloride and hydrogen), but it consumes more zinc than is consumed in cleaning new steel.

Cavities of small volume (say under 50cc) require one hole to release pressure.

Cavities of larger volume require two holes. One to let air out, the other to let molten zinc in. The problem, (other than those above) is one of buoyancy. Unless the air can be replaced with zinc, it causes the steel item to float in the zinc. Zinc and steel are of similar density, steel a little heavier, and any significant air inside makes steel buoyant.
The upside of letting zinc inside the cavity is that it gets galvanized too, and to the same extent as the outside. These holes are usually called "vent and drain" holes in the industry.
 
vyv_cox: Did I say not say there were no anchors with lead in. What I said was I had never met one. Maybe that is because it is only worth re-galvanizing those anchors that get used and the boats I associate with use their anchors! Lead is soft and after a few years you would see the lead being deformed and marked in the pour hole. Lead is easily scratched and simple to drill. Even hitting it, will sound different. On a CQR there are two welds down the sides of the insert and the inset has a ridge in the middle. A 1 inch hole would disrupt that pattern noticeably.

However, I did call Simpson Lawrence tech. dept. over the void issue, and they also assured me that their CQR anchors have no lead.

MM5AHO: It is not the zinc that is the issue with re-galvanizing it is all the rust, gunk, and ****. Getting through to clean metal all over is critical before the dip. It requires care and costs in acid. Without full cleaning, the zinc looks like a bad case of chicken pox!
 
halfway said:
However, I did call Simpson Lawrence tech. dept. over the void issue, and they also assured me that their CQR anchors have no lead.
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My apologies if I was incorrect. I have found many references to lead tips in CQR anchors, including the one I quoted about older Simson Lawrence ones. I accept the SL statement.

However, the Plough, a CQR clone, most definitely does have a lead-filled tip, shown on many websites.
 
Halway wrote:

MM5AHO: It is not the zinc that is the issue with re-galvanizing it is all the rust, gunk, and ****. Getting through to clean metal all over is critical before the dip. It requires care and costs in acid. Without full cleaning, the zinc looks like a bad case of chicken pox! "

Yes thats right. Galvanizing isn't just a coating, its an alloyig reaction and it doesn't take place with oxidised steel. All rust etc must be removed. But thats what the acid immersion is for. It will clean inside cavities provided it can get in and out and when depeleted, that fresh acid will get in. A tiny hole typically doesn't let enough acid flow. Caviteis require longer acid immersion.
But acid isn't all that expensive, and cleaning rust doesn't consume much of it. Consuming old zinc uses a lot more acid.
 
Sorry Vic that is Steel. It is welded in and galvanized on the top. I think it is a forging. It is the basis of the strength of the point.

(Well actually it is mud on the point.)
 
halfway said:
vyv_cox: If you could point to a picture of a lead plough it would help with identification. I looked and there were very few pictures from below. I did however find a picture of one labled as a Genuine CQR which was actually a fake.

The best picture of a standard CQR looks like:

http://upload.wikimedia.org/wikipedia/commons/archive/d/d9/20060514130758!Anchor_CQR.jpg
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http://www.hillarysboatshop.com.au/home.php?cat=107

http://en.wikipedia.org/wiki/Anchor#CQR.2FPlough
Quote
Owing to the use of lead or other dedicated tip-weight, the plough is heavier than average for the amount of resistance developed, and may take a slightly longer pull to set thoroughly. It cannot be stored in a hawse pipe.
 
vyv_cox: That picture on the shop site gave me a chuckle. Draw an imaginary line across the base and then a line down from the mid joint to the base line. This anchor has more metal behind the hinge! I suggest that this one needs someone to stand on it, to make it set.

Notice how the welded frame construction is welded to the top of the blade whereas the CQR is welded onto the forged V insert at the back of the blade V. I would suggest that anchor would never get used enough to ever need re-galvanizing. Who makes it? Is there a manufacturers site? It is strange they do not even reference the manufacturer.

As for the Wiki entry. Could I refer you to the shaping of the shank on the so called genuine CQR photo. Try finding the source of that picture! Wiki is not evidence. Just popular truth.
 
VicMallows said:
Not really worried WHAT is in the tip.....all I know is that once it has dug in it is
excellent;...but other than in soft mud trying to get it to dig in is a real pain. Lived with it OK for 25 years, but think maybe time to try a 'modern' anchor.(No, not starting that debate on this thread!)

Vic
Click to expand...

I reckon it's inevitable - quite clearly a chain reaction !
 
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