Copper versus Brass Plates - Pros and Cons

[knightyo]

Hello,

 

Back around 2008, I used what I "thought" was copper tape to plate the hull of my Syren.  I've always been curious as to why my copper plates didn't ever appear to "age".  Wefalck mentioned in one of my posts that it appeared that my plates were constructed from copper painted paper as opposed to actual copper tape.  This makes sense as you can see that the "paint" is flaking from the paper in the below photo.   Soo..... This is irritating. 

 

Now, how to remedy?  I've been thinking about redoing the plates with legitimate copper tape for the next go-around.  However if I'm going to invest that much time in redoing the plating, I want them to look far more authentic.   The very bottom photo is from Alex Baranov's Cumberland log which I find to be striking.  However Alex creates his plates from brass.  I've been scouring the web for tutorials on this process, but have been coming up empty.  Yes, I've been tempted to send him a message requesting assistance, but don't want to impose; especially if there are readily viewable tutorials out there that I just haven't yet found.

 

Is anyone aware of brass plate tutorials?  I guess I'm not wedded to the idea of brass... I just want my "next" plates to look more like Alex's than my own feeble 2008 attempt. 

 

Alan

 

 

 

 

 

 

 

 

Edited February 14, 2022 by knightyo
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[allanyed]

Your attempt is superior to the vast majority seen on build logs here at MSW.  You show dimples instead of pimples which is realistic, albeit a bit larger on the inside ones than the peripheral rows.  Those indentations on the edges look much closer to scale of using 1/4" nails with 1/2" flat heads.   And, unlike the vast majority of copper sheathing on models we see here, your plates overlap as they should be.  Kudos to you for this.   There is a tutorial by Gene Bodnar at NRG that is not bad, but uses copper tape, not brass.  I don't know if it really is copper or painted as was yours.     https://thenrg.org/resources/Documents/articles/CopperSheathingaHull.pdf

 

On the actual ships the coppering was no doubt green in short order and there are some nicely sheathed models with the plates painted an oxidized copper green as an alternative route you might want to consider.

 

Allan

Edited February 15, 2022 by allanyed

[knightyo]

Thanks Allan, I really appreciate it.  It is mighty tempting to apply an oxidized copper green to these; that's a fantastic alternative idea if I don't in fact replace these plates.  I do have to admit that the out of scale dimples I created have also bugged me a bit, however I suppose a paint application would also fill those in a bit as well.  It looks like there's a good deal to consider on this one. 

 

Alan 

 

[Gregory]

Have you ever worked with copper leaf?

 

The link  above starts off talking about gold, but makes it clear it is copper if you choose it from the various options.

It might make a good covering for your existing work.  My experience is that it goes on almost like  paint and is seamless.

 

I used it to cover the the cupola of the companionway on my Resolution.

 

It goes on as very shiny copper, but a patina can be created in various ways.

 

[knightyo]

Thanks Phil, that cupola looks fantastic.  I might indeed need to experiment with that as well!

 

Alan

[wefalck]

I agree with Allan, that you did a pretty good job at the coppering as such!

 

The question now is, what material did you actually use? This would determine how to repair it short of stripping and re-doing it. The flaking you observe means, that the bond between the 'copper' layer and the backing is failing. Now, whatever you will put on that, be it paint or metal leaf, will come off again, as this bond seems to fail. So that needs to be investigated firs.

 

I have to disagree with Allan over the colour of ageing coppering. The green colour one sees on old coppered roofs is due to copper-sulfates, where the sulfur is derived from the sulfur contained in coal fumes and the likes. Seawater contains sulfate, but it appears that the copper immersed into seawater is rather first oxidise. It forms a very thin reddish-brownish oxide layer that 'passivates' the copper and protects it from turning into copper-sulfate. In the area between wind and water, however, the copper-sulfates may form. This, at least, seems to be my experience.

 

Some ships have been sheathed in Muntz-Metal, which is a copper alloy close to brass, but contains proportionally more copper. One has to check on the Internet, but I think it has not been available before middle of the 19th century, so may not be appropriate for your ship.

 

If you can satisfy yourself, you could try to touch up the areas that have lost the coppering with some rub-on copper paint and then give the whole underwater body a washing in dilute brown paint to blend in those areas. I first would experiment with that off model, of course.

[allanyed]

2 hours ago, wefalck said:

Seawater contains sulfate, but it appears that the copper immersed into seawater is rather first oxidise. It forms a very thin reddish-brownish oxide layer that 'passivates' the copper and protects it from turning into copper-sulfate. In the area between wind and water, however, the copper-sulfates may form. This, at least, seems to be my experience.

Thanks for this information Eberhard, it makes for a very good day for me learning something new first thing in the morning! 😀 Is the below from the Constitution what your are referring to color wise?  

Allan

[wefalck]

Yes, the copper seems attain this dull reddish-brown colour under water. Another example here from HMS GANNET:

 

 

The greenish colour seems to be more in the area of changing exposure. I don't have a picture at hand, but on ships taken out of the water, the dull reddish-brown colour of oxidised copper seems to extend over the bottom. However, it also depends on the environment in which the ship is kept. HMS GANNET is in a dock of Chatham dockyard and I don't know how saline the water is - the salinity would change during the tides, as it is located at an estuary.

Unfortunately, there are not too many operational ships with coppered bottoms around anymore, so that one can have look, how the operational environment effects the appearance of the bottom. I remember having seen the 'Stockholm Briggen' (a replica built some years ago), laid up for winter in Stockholm harbour and as she was riding quite high, one could see that the waterline was marked by a green-greyish corrosion layer, while the copper above and below had this dull reddish-brown colour. However, the salinity of the Baltic in Stockholm is quite low.

 

To the contrary this is what happens when a coppered ship sits in a dry-dock for a few years:

 

 

As the Fragata DON FERNANDO II E GLÒRIA had been moored off Lisbon in the Tagus river before beeing restored, perhaps one can find some pictures that show her bottom, when she was taken out of the water. However, this would again reflect what happens to the copper in a brackish environment and when stationary.

 

BTW, CUTTY SARK's bottom is covered in Muntz-Metal rather than copper.

Edited February 15, 2022 by wefalck

[knightyo]

6 hours ago, wefalck said:

The question now is, what material did you actually use? This would determine how to repair it short of stripping and re-doing it. The flaking you observe means, that the bond between the 'copper' layer and the backing is failing. Now, whatever you will put on that, be it paint or metal leaf, will come off again, as this bond seems to fail. So that needs to be investigated firs.

 

Yep, I've been pondering this as well; additionally, anything applied over the top might actually accelerate the flaking just due to added weight.  It seems like if the plates are to remain on the hull,  some type of medium would need to be applied which would flow into the edges and dimples of the plates in order to keep everything locked into place.  The unfortunate part of this plan however, is that the plates overlap each other from the top down, so there aren't "shelves" along the tops of the plates that a sealing agent could rest upon.  

 

I just found the tape I used back in 2008.  It turns out that it was 1/4" .0015 Copper FOIL tape.  This does seem to explain the current dilemma.   I think I have some Googling to do on this issue.

 

Alan

 

[wefalck]

Did this foil tape have a paper backing, or just an adhesive, but on a paper carrier? From the first photograph it appears, that there is some paper from which the copper has been flaked off, correct?

 

I am curious about this, as I have some very thin copper tape, but it is self-adhesive on a protective paper-backing.

 

There are probably different varieties, but there is also one that is used in making stained glass windows or 'Tiffany'-work - the pieces of glass are framed with the tape and then soldered together. So the adhesive should be pretty good.

 

It looks now that the very reason of the overlapping on the prototype - to prevent ingress of water and nasty beings, defeats your ideas of infiltrating the material to re-enforce the glueing.

 

Metal objects are traditionally coated in a special varnish to prevent tarnishing, which at least over here in Europe goes under the name of zapon-varnish. It forms a very thin, continuous, practically invisble layer. Minwax has a similar effect und is also used by museums. After patching up the bad places, you could apply a coat and this should prevent at least for some time the flaking. The varnish can be dissolved easily with acetone and Minwax dissolves in alcohol I believe, making this procedure reversible to a degree.

Edited February 15, 2022 by wefalck

[Roger Pellett]

For those interested, the book Ships’ Fasteners by Michael McCarthy and published by Texas A&M Press includes a chapter on Muntz Metal and its relationship to composite ship construction.

 

According to the book, Muntz Metal is a 60-40 copper zinc alloy.  It was patented by Birmingham England metal founder George Muntz In 1832.  By 1840, it was available in quantity.  It’s ease in rolling  into thin sheets and reduced copper content gave it a cost advantage over copper.

 

In 1847, Muntz lost his patent protection and needed to look for new products.  He discovered that by further reducing the copper strength of his alloy to 56% it gained considerable strength, comparable to wrought iron.  He then developed a line of Muntz Metal bolts.  When composite ship construction  began, treenails could no longer be used to secure wooden planking to iron framing.  Iron bolts in contact with tannic acid bearing oak planking were subject to corrosion.  The solution was Muntz Metal bolts.

 

Cutty Sark, beloved by thousands of ship modelers is a composite hull ship.

 

Roger

[rwiederrich]

Plus the varnish may similarly react with the metal finish and aid its retention to the paper backing.  In essence *gluing* it to the backing.

 

Rob

[wefalck]

That's what I was implying ...

 

[knightyo]

1 hour ago, wefalck said:

Did this foil tape have a paper backing, or just an adhesive, but on a paper carrier? From the first photograph it appears, that there is some paper from which the copper has been flaked off, correct?

 

I am curious about this, as I have some very thin copper tape, but it is self-adhesive on a protective paper-backing.

 

There are probably different varieties, but there is also one that is used in making stained glass windows or 'Tiffany'-work - the pieces of glass are framed with the tape and then soldered together. So the adhesive should be pretty good.

 

 

 

The tape does indeed have a paper wax-type backing.  The copper peels off of the backing for installation, and has an adhesive on the back side; there's definitely nothing but "sticky" copper on the back side.   I've tried to replicate the flaking on a sample piece I just took from the roll, but ironically could not get it to flake.  I'm a little mystified.  If I can get the nerve up, I might try to further "flake" that section of the hull when I get off work. 

 

 

 

 

[wefalck]

Yes that looks like the tape I've got.

 

Somehow, that 'flaking' is a bit strange. With real copper one shouldn't have flaking, but a whole sheet coming off.

[rwiederrich]

17 minutes ago, wefalck said:

Yes that looks like the tape I've got.

 

Somehow, that 'flaking' is a bit strange. With real copper one shouldn't have flaking, but a whole sheet coming off.

I agree.  Copper tape once removed from its paper backing does not flake.  It is entirely copper, it would de-glue and come off the hull as an entire plate..  Not like what might be seen on a silver plated copper ring.  Then again...that doesn't *Flake*, but wear's off.

 

I'm not entirely sure what type of copper plating the O/P originally used on his hull.  Without actually seeing with my own eyes up close...and only having the image he provided...it looks more like some form of etching is taking place then *flaking*, where as a touch of paint and some varnish might just be the corrective ticket.  Short of removing it all and re coppering.   That just doesn't sound fun at all.....not even just now as I said it.

 

American pennies are copper plated zinc...and the copper doesn't flake off but can be rubbed or polished off.   Interesting situation...we have here.

 

Rob

[catopower]

Knightyo, I don't mean to be disputing your memory on your build. But, I have seen this kind of thing before. And as I recall (my own memory may be very disputable here), it wasn't so much an issue of the copper flaking off, but some coating/finish applied to the completed model that has worn or flaked off, leaving partial exposure.

 

Or possibly that something spilled on the copper which was not initially noticeable, but caused the copper beneath to tarnish at a different rate from the rest of the hull. Maybe something like CA that was used to help affix/repair some tape that didn't adhere well?

 

This small blemish aside, you're coppering job looks excellent. 

 

 

Edited February 15, 2022 by catopower

[knightyo]

I think the mystery has been solved.  I very gently felt the areas of concern under my magnifying station using a few different instruments, and could not feel any "edge" to the discolored areas at all; I could have sworn that there would have been edges.  I think the hypothesis that the plating has been affected by accidental contact to some other substance is correct.  I also worked around one of the edges to see if I could get it to flake, but there was no discernable transition from area to area. 

 

Now I feel comfortable moving forward with trying to "age" them a bit more, especially if something can be applied which will slightly fill the dimples bringing them a little closer to scale.  I still have the jig used to create these plates; I might press a bunch more plates and then experiment on them with different mediums. 

 

Thank you everyone for your help with this!  I sincerely appreciate the input; especially for something that I should have been able to figure out on my own. 

 

Alan