Copper plating any advice on the jig

[Bob Cleek]

7 hours ago, RichardG said:

I think the problem with scale in terms of getting it accurate from viewing distance is valid. You would not able to see any specific nailing pattern. This is a picture of the Constitution's coppering.

 

So although the nailing pattern disappears, the hull plates do not look smooth even when viewing from a distance. Now I need to go out and see from how far away I can see the rivets on a semi trailer 😀.

Yes, well... that's USS Constitution's coppered bottom after her latest restoration, I believe. As discussed here in another post which included pictures of that copper being applied, it was noted that "the hull plates do not look smooth even when viewing from a distance" because the workmen who applied them did a poor job of it. Critically, they used carpenter's hammers to drive the copper tacks instead of a proper coppering hammer with a wide slightly convex face which drives the tack nearly flush with the plate without unduly denting or distorting the plate. The object of it all is to make the bottom as smooth as possible. The more texture to the bottom, the more resistance to the water and the slower the boat sails.

 

Ham-fisted workmen making a mess of USS Constitution's copper plating using flat faced sharp edged carpenter's claw hammers:

 

 

Cutty Sark's newly replaced bottom sheathed with Muntz metal (a type of patent brass) showing the use of proper hammers by skilled workers:

 

 

 

Close up of Cutty Sark's Muntz metal sheathing:

 

 

Coppering hammer:

 

 

 

See:         C. DREW Coppering Hammer (numismalink.com)              

 

Edited July 28, 2021 by Bob Cleek

[rwiederrich]

I designed a copper plate simulator by way of using a piece of wire fence.....drywall sand paper and a wash bin roller.

 

The simulated nail imprints are convincing IMV, and from a scale distance look fine.  Here is a batch of finished strips and applied strips.

 

This method is fast and I think is accurate enough in my scale of 1/96 

 

Check out my *Glory of the Seas* Log in the scratch build section.

 

Rob

Edited July 28, 2021 by rwiederrich

[knightyo]

Just a quick note about copper tape.  This zoomed-in photo shows the copper tape I used for my Syren.  The tape was applied around 2008 or 2009.   In the middle section, you can see where "flaking" is taking place.   I'm not sure if all copper tape is like this or not.

 

Alan

 

 

[Jaager]

16 hours ago, Bob Cleek said:

Yes, well... that's USS Constitution's coppered bottom after her latest restoration, I believe.

It looks horrible and tacky,  I wonder if the copper on a roll that is used for roof flashing was used.  It looks so thin and dents so easily.  The lengths of the "plates" look too long.

If the ship is afloat, what is below the waterline is unseen.  I would wonder if Boston harbor is warn enough for there to be a problem with shipworm mollusk larvae?   If the gauge of the sheathing is as thin as it appears, blunt force scrapping of barnacles. mussels, and seaweed would probably damage it.

[Roger Pellett]

Do modern marine anti fouling paints provide protection from shipworms?

[Jaager]

If the coat is continuous with no communication between seawater and wood, in theory the microscopic larvae would not detect the presence of wood to invade it.

 

I think I wrote this before,  I do not think that the actual copper was the protection from the mollusk.  It was a protection for the fragile protection layers.  The copper was also a surface that offered a less tenacious hold for seaweed and barnacles.  There was the actual plank bottom, then a a tar - felt - organic fiber layer that was toxic for the larvae, then a softwood sheathing, then copper.

The mollusk lives its development, and wood eating stage within a single piece of wood. It does not migrate to another board.  The softwood sheathing scarfs up the microscopic wood seeking larvae.  The joins of copper plate to copper plate was not welded.  Water must have been able to penetrate. The gaps would have been a wide open highway for  microscopic larvae. 

[RichardG]

5 hours ago, Jaager said:

I wonder if the copper on a roll that is used for roof flashing was used.  It looks so thin and dents so easily.

According to Mark Staniforth's "The Introduction and Use of Copper Sheathing - A History" they used copper between 20 and 32 ounces per square foot in the Royal Navy. If my Google search is correct, that's 22 - 19 gauge. 0.027" to 0.043", 0.69 to 1.09 mm. 

 

"In the 1927-1931 extensive restoration of Constitution the final restoration report tallied the following about the copper:

 

Ship has been copper sheathed from keel to 23’ 6” aft and to a height of 21’ 0” forward – 3,400 sheets of copper, 14”x 48”, in various weights; 28-oz. between keel and shoe, 26-oz. at turn of bilge and at water line; remainder 22-oz., all of which is secured to wood planking by 1 1/8” and 1 ¼” copper sheathing nails.  Approximately 12.5 tons of sheathing copper, 1600 pounds [copper] sheathing nails,  38.4 tons new copper fastening[s] used; 4 tons old copper fastening [reused?], 8 tons old copper left in ship; a total of  63.7 tons of  copper now in the ship. [Commandant, U.S. Navy Yard, Boston, “U.S. Frigate CONSTITUTION (IX21) – Research Memorandum”, 1931, 60.]" https://ussconstitutionmuseum.org/2015/08/12/copperbottomed/

 

You can see a video of them preparing the sheets here 

 

 

 

 

Edited July 29, 2021 by RichardG

[wefalck]

@knightyo, it appears that you picked copper-painted paper, rather than real copper-tape. Copper-tape today is available in various thicknesses and presumably with various adhesives. It seems to be used in various industrial applications as conducting tape. Another tradtional handicraft application is in stained-glass window and object fabrication, where each piece of glass is surrounded by copper-tape that is folded into an U-shaped channel; the pieces then are soft-soldered together. This tape is much thicker than that for industrial applications.

 

I probably made this point earlier: coppering in seawater develops after a while a dull brownish-red oxidation surface. So the question is how you want to present your model, in working-day appearance or as a show-piece of your craftsman skills.

 

In the latter case, I would not worry too much about the initial appearance of the copper, it will develop a dull reddish surface over the years, if not varnished.

 

I don't know how at that time the sheet-copper was treated after rolling, but I could imagine that it was given a rub down with chalk after annealing between and after the rolling passes to remove scale. So, the plates probably would have had a clean uniformly copper-coloured satin surface. Therefore, I would not worry about giving the plates a different appearance. Any colour differences would even out after a while in the seawater.

 

The effect of 'coppering' is probably based on a collection of processes, also depending on the species against which one wants to protect the ship. The copper plates are applied over a layer of tarred felt. Tar contains lots of unhealthy compounds, including polycyclic aromatic hydrocarbons (PAHs) and phenols, which probably would cut short the life of many nasty little things. The copper itself is smooth, making it difficult for barnackles and seaweeds to get a foothold. If they can get a foothold, say at the seams, they may dissolve some of copper - while copper is an essential element for many living things, too much of it is not very healthy. Then the copper surface is constantly, but slowly, eroded by forming copper-oxides and -sulfates, which again makes it difficult for unwanted growth to get a foot-hold. So overall, the copper-sheathing is a 'defence in depth', with various complimentary mechanisms.