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Author Topic:   Identifying and Authenticating Old Sheffield Plate (fused plate)
burwoodhall

Posts: 41
Registered: Sep 2006

iconnumber posted 09-27-2006 01:11 AM     Click Here to See the Profile for burwoodhall     Edit/Delete Message   Reply w/Quote
[26-1210] [08-0503]

I am a first time member and have been searching this site as suggested before posting my question. Please excuse me if my question is redundant of anything already available.

I love collecting silver and have been doing this for about a year now, I have bought several hundred dollars worth of silver books on hallmarks etc, checked out numerous books from the library and searched the web trying to educate myself. Thank you for having this forum site.

As a collector, I am looking for the "Old Sheffield Plate" items and have bought things thinking they are OSP and then find that they are not. Is or are there any "technical" guides that help one determine if an unmarked silver item is OSP because purportedly 75% of the OSP produced was unmarked. The books say that OSP could have seams inside pots, could have tin in places where silver would not show, and has applied edges to hide the layers of sterling, copper, and third metal either another layer of sterling or tin or pewter? But besides this, what other telling signs would indicate an item is OSP based upon its construction? for example how were handles on trays applied? Were knobs and handles made from SOLID sterling either casted or formed and then bolted on? Would a soldered on handle indicate silverplate? Would a silverplated handle and what appears to be an OSP body indicate a transitional period piece (after electroplating came into existance)or would it indicate that the whole item is silverplate and NOT OSP?

How can you tell if an electroplated item is really an OLDER OSP item has been electroplated?

Does anyone have some academic pictures of OSP items with detail shots of how the edges are treated to hide the seams, how ornamentation is treated? How handles are soldered on or whether they would never be soldered?

Is there a scientific test that would indicate OSP vs silver electroplate?

How thick was the layer of sterling in the OSP process?

Thank you in advance...Hilda

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DB

Posts: 252
Registered: May 2006

iconnumber posted 09-27-2006 06:09 PM     Click Here to See the Profile for DB     Edit/Delete Message   Reply w/Quote
Most of your questions are beautifully answered in
Stephen J. Helliwell: Antique Silver Plate, Suffolk 1996
an Antique Collector's Club book

If I would collect OSP I would only buy pieces which are marked, since your monetary outlay is better protected this way.

------------------
Dorothea Burstyn

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blakstone

Posts: 493
Registered: Jul 2004

iconnumber posted 09-27-2006 08:31 PM     Click Here to See the Profile for blakstone     Edit/Delete Message   Reply w/Quote
I'm sure others will contribute with their suggestions, but here are a few of my tips. I catalogue silver for an auction house, so the OSP vs. EPNS question is an academic one for me, since I'm not a collector of either. And remember, these are merely tips: there are no absolute rules.

First, familiarize yourself with styles. Even though old styles are revived, the relatively short-lived OSP popularity and its near-immediate replacement with electroplating make a thorough knowledge of popular styles the first tool in your arsenal.

Second, look for the "lip" on edges: this is created when either the silver sheet has been cut on a bevel and folded back on itself, or a thin, flat wire is applied over a straight cut edge to hid the copper. As a rule of thumb, the longer this lip, the older the piece.

Third, check handles and feet. On Sheffield Plate, these are generally made of two die-stamped halves, soldered together and filled with lead; look for the seam. Electroplated pieces can be plated in the round, and are therefore often cast that way. (And avoid pieces that are damaged here, with the lead exposed and/or coming out of the seam; they are nigh impossible to repair!) Some pieces do have (invariably detachable) sterling handles, but these will always have the proper hallmarks.

Fourth, check the decoration. Since excessive engraving would cut into the copper underlay, OSP surface decoration is often limited to flat-chasing or shallow engraving. Electroplating can be done after this work is finished, so the engraving here can be as deep as the maker wants. (Note, too, that the technique of inserting a thicker silver plaque in the center of OSP salvers and platters for an engraved crest was perfected around 1810-1815; try letting your breath fog up the crest and look for the distinct line of the plaque surrounding it.)

Fifth, train your eye (and nose!) Since OSP has a layer of alloyed silver, it will have the warmth and glow of sterling. The thin coating on electroplate, however, is pure silver: harsher and whiter. (This is one of the most difficlut talents to master but, I find, far and away the most reliable.) Likewise, OSP often has that familiar "silver" smell; EP almost never does.

Like I say, just a few tips; hope they help.

P.S.: My friends here would be think it odd it I didn't inject a bit of my passion: remember that some very fine fused silver plate was made in France as well. These Restauration treasures are often ignored and can be quite magnificent.

[This message has been edited by blakstone (edited 09-27-2006).]

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Dale

Posts: 2132
Registered: Nov 2002

iconnumber posted 09-27-2006 10:55 PM     Click Here to See the Profile for Dale     Edit/Delete Message   Reply w/Quote
Everything Blakstone said; especially the style part.

'How can you tell if an electroplated item is really an OLDER OSP item has been electroplated?'

You generally can not tell with any degree of certainty. My first clue is the style. My second is that if it says Sheffield anywhere on it, it isn't Sheffield.

Later plating is sometimes very hard to figure out, especially if it is well done. It is possible to give electroplate a blue cast which very much mimics the look of Sheffield.

The only other thing I would have to say is to look for a 'grain' which is probably the wrong word. Silver that has been worked by hand frequently shows a 'grain'. Electroplate is a fairly even deposit which is uniform. This is more likely felt than seen. Run fingers lightly over the piece to see if you can detect any direction.

On the end of fusion plate; my understanding is that certain types of items were made from fusion plate well beyond the 1850's. Particularly larger trays and domes as well as hand mirrors and some dresser items. The clue here is to look for a need for strength which neither sterling nor electroplate on brittania metal would give. As well as some types of jewelry, particularly very fancy hair ornaments, made into the 20th century from a copper and silver sandwich. It looks that fusion plate died out in mainline silver, with some few exceptions, but lingered in allied trades for a while.

Did read that well into the 1990's Rolls Royce used sheffield plate for cooling radiators on jet engines. Silver is a great metal for controling temperature.

[This message has been edited by Dale (edited 09-27-2006).]

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ahwt

Posts: 2377
Registered: Mar 2003

iconnumber posted 09-28-2006 12:05 AM     Click Here to See the Profile for ahwt     Edit/Delete Message   Reply w/Quote
Another good book on Sheffield plate is “Sheffield Silver Plate” by G. Bernard Hughes published in both England and the United States in 1970. This book has an excellent chapter on identifying Sheffield plate as well as a very informative chronology of Sheffield plate. For example, the invention of solid plated wire dates to 1770, the introduction of the silver-lapped edge occurred in 1775, while the soldered-in heavily silvered shield for a coat of arms was introduced in 1790.

Hughes also has several chapters that explain the various techniques for decorating, making edges and mounts, making hinges, and other manufacturing processes. Sheffield plate is sterling silver (of various thicknesses) fused over copper and it acquires a bluish tint through the years. The copper that occasionally shows through I think just adds to its charm.

One of the best ways to learn more about Sheffield plate is simply to go to antique shows and ask dealers if they have any Sheffield plate for sale. Good dealers will be glad to show you their wares and to explain these pieces to you. There is of course a danger in this as Sheffield plate can be quite alluring and you are likely to buy some of these attractive pieces.

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ahwt

Posts: 2377
Registered: Mar 2003

iconnumber posted 09-28-2006 12:30 AM     Click Here to See the Profile for ahwt     Edit/Delete Message   Reply w/Quote
You also asked about the thickness of the silver. Hughes in his Chapter 4 states that normal thicknes was one-fortieth that of the ingot: 10-12 ounces of silver to eight pounds of copper. Second-quality Shefield was made from 1815 on wherein the silver was reduced to eight ounces for every eight pounds of copper. Deep cut engraving required at least 14 ounces of silver to eight pounds of copper.

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burwoodhall

Posts: 41
Registered: Sep 2006

iconnumber posted 09-28-2006 01:14 PM     Click Here to See the Profile for burwoodhall     Edit/Delete Message   Reply w/Quote
Thank you all for the great info. I am out of town right now (my only daughter just had my first grand baby)but when I get back home I will be searching for more books. My time now is spent, shopping, cooking, cleaning etc etc...

In the past I've gone to museums looking at silver but of course you can't touch or examine it up close (looking for seams, construction, etc).

Are there any close up pictures on any known websites of OSP items that show magnified details of construction? I have looked at some pieces on the internet but they don't generally show construction details just the object from a distance or a hallmark if available. Do any readers of this site have such close up pictures of their own treasures showing handle application, feet application, rims etc?

I also heard that they tried making OSP flatware too but that didn't work well. Any truth to that? Thank you ALL again. Hilda


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blakstone

Posts: 493
Registered: Jul 2004

iconnumber posted 09-28-2006 03:04 PM     Click Here to See the Profile for blakstone     Edit/Delete Message   Reply w/Quote
quote:
I also heard that they tried making OSP flatware too but that didn't work well. Any truth to that?

Yes; the copper interior couldn't stand up to the constant wear that flatware endures, and the sharp, narrow edges of spoons & forks left too much of the base metal core exposed. There was a technique known as "close plating", where a sheet of silver foil was adhered to steel by means of a flux amalgam, that was used on dessert sets, buttonhooks and other items which required strength. Close plating was the only method of plating steel even after the introduction of electroplating, which tended to rust the steel. As a result, close plating survived well into the 19th century. Close plate items can usually be identified by their steel base which is often exposed, since the technique did not create items which could last too terribly long; certainly not centuries. The "foil" nature of the silver that remains is usually readily identifiable, as is the typical "blistering" that can occur when when the steel core has rusted or corroded in spots.

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burwoodhall

Posts: 41
Registered: Sep 2006

iconnumber posted 09-28-2006 04:21 PM     Click Here to See the Profile for burwoodhall     Edit/Delete Message   Reply w/Quote
Hum "close plating" thats helpful and new to me. It makes me think of these knives I have back home. I have 4 old silver handled knives whose blades show this "bubbling" or blistering and I thought the blades were just silverplate that had separated from the base metal through breakdown of the base metal. thus I thought the entire knife was just silverplate since I figured the blade was electroplate.

Is it possible the knife blade is close plate and the applied handle could be sterling, should I look at those handles more closely, they're worn smooth near the area where one usually finds the hallmarks? Or is it more likely the whole thing would be routinely silverplate?

So, do you know when they began or created this "closed plate" method? It sounds like close plating was similar in design to OSP except that the thin sheet of sterling in close plate was "glued/bonded" to steel and the OSP was hammered/pressed or forged onto the base metal?

did they do close plate in the 18th century?

Also do you know what kind of cement they used to bond the fork or knife blade base down into the handle? Is something available today to "reglue" these items that have dried out and fallen out of their handles? I am here in Florida and I just went though a wash tub, yes a wash tub, of old silver plate at an antique mall.

I found 4 pieces of coin and two knives and two matching wierd pronged forks that scream old and German. I just located on the internet info that says one impressed mark (pomegranet over a R) means Augsburg. R is the date letter and based on the style of the R could be 1783 or 1806 based upon the Pomegranet over a T that I found associated with another object which supposedly is 1811. on the otherside of the knife/fork handle is an impressed FED or EED. On the blade of the knife is H. Mueller below which is Wurtzburg with 2 dots over the u. The fork neck and tongs and knife blades look like they are solid silver but could they be "closed plate" with no bubbling?

Very interesting...Thank you....

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burwoodhall

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Registered: Sep 2006

iconnumber posted 09-28-2006 04:30 PM     Click Here to See the Profile for burwoodhall     Edit/Delete Message   Reply w/Quote
This is Hilda I spelled 2 words wrong. It is Wurzburg and H. Muller..

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blakstone

Posts: 493
Registered: Jul 2004

iconnumber posted 09-28-2006 11:02 PM     Click Here to See the Profile for blakstone     Edit/Delete Message   Reply w/Quote
The close plating process was patented in 1789 by Samuel Roberts, a Sheffield plater. Most pieces date from the 19th century, though, and up through WWI – not coincidentally concurrent with the 1913 invention of stainless steel by Sheffield native Harry Brearly. I don’t recall ever seeing a close plate set with sterling handles, but they may well have been made, but – again – they would both be marked accordingly. (Close plate is sometimes, but by no means always, marked “PS” for “plated steel.” ) Close plate flatware is usually limited to fruit or dessert sets with ivory, mother-of-pearl, ebony, etc. handles, but certainly whole flatware was made in the process. A wide variety of nutcrackers, corkscrews, skewers, carving sets, etc. were made this way: pretty much anything that required the hardness of steel.

An item was completely fashioned out of steel and then brushed with sal ammoniac (acting as a flux) and then dipped in molten tin. Silver foil was then applied and the whole item burnished with a hot soldering iron. This melted the tin and, with the help of the flux, fused the silver to the steel.

I don’t know if the process extended into Germany, but it was, as I say, the only way to silver-plate steel. Your Augsburg set with the year letter “R” below a pinecone (not a pomegranate - a pinecone has been the symbol for Augsburg since before the 13th century) might be 1806, but is more likely from 1831 – the third cycle of Augsburg date letters. The maker “FED” (there was no “EED”) was Friedrich Ernst Dassdorf, master 1803, d. 1841. He could have made something in 1806, but the “FED” mark is more common later; his early mark was “FD”. H. Müller (or Mueller) is almost certainly the cutler (knife blade maker – a different craft from silversmithy with a different guild); Würzburg is a German city in Bavaria about 150 miles from Augsburg.

Hope this helps!

PS: Blades and tines were generally fixed into hollow handles with pitch (a sort of tar) or, less commonly, plaster (which didn't hold up as well). There are some talented craftsmen today who can repair these, but they are few and far between; try checking the ads in Silver magazine (shameless plug).

PPS: I know what you mean about not being able to examine items in a museum, but you'd be surprised how accommodating curators can be when you get to know them; they're just as proud of their collections as anyone else! Also, you might try previewing sales at upscale auction houses (another shameless plug).

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burwoodhall

Posts: 41
Registered: Sep 2006

iconnumber posted 09-29-2006 12:54 PM     Click Here to See the Profile for burwoodhall     Edit/Delete Message   Reply w/Quote
Thank you so much. I am so amazed and appreciative of all this knowledge you have about silver. Where ever did you find the info that translated FED to a name and the pinecone info? I found a site previously that appears very helpful and complete (I won't mention the name because it might not be consistent with this sites rules) but it showed the mark under Germany pre 1886 and said it was a pomegranet mark used since 1763 so hense my reference to that. As soon as I have access to a digital camera I'll try my luck at posting some detailed pictures of my (hopefully OSP tray) to see if my instincts were right on this one piece and if not learn from my mistake. Again, thank you and everyone who participated in this discussion. Hilda

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swarter
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Registered: May 2003

iconnumber posted 09-29-2006 11:28 PM     Click Here to See the Profile for swarter     Edit/Delete Message   Reply w/Quote
quote:
How can you tell if an electroplated item is really an OLDER OSP item has been electroplated?
Does anyone have some academic pictures of OSP items with detail shots of how the edges are treated to hide the seams, how ornamentation is treated

One way to tell OSP is that the construction techniques were the same as for silver - you can see hammer marks and center punch marks (if the bottom is exposed), neither of which would you see on electroplate.

Here are two OSP pots, a Rococo coffee pot of the 1770's on the left, and a Neoclassical covered jug of somewhat later vintage.

In the pictures below, the coffee pot is early and shows the way seams are hidden - the spout was cast in two halves, and the seamed joints are covered by beaded strips. The jug shows the way the coppeer edge on the lip is hidden by applied beading, and the reserve shows the thickness of the silver layer by showing no copper in the bright cut engraving. There is also some "bleeding" of copper where silver on the high points of the embossed swags is wearing away.

The coffee pot also has a seam, visible on the inside, that is detectable on the outside only by a faint line of air bubbles barely visible in the solder. There are also hammer marks visible inside. The making of jug is more sophisticated, and is better finished, showing little of the hammering and seaming.

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burwoodhall

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Registered: Sep 2006

iconnumber posted 10-01-2006 01:17 PM     Click Here to See the Profile for burwoodhall     Edit/Delete Message   Reply w/Quote
Thank you for the excellent info and the time you spent putting up these excellent photos as examples for readers interested in OSP and in response to my request. This was very helpful. In looking at the pictures I am curious as to how the craftsman treated the area of the tip of the pour spout as that is a circular opening and would show the 3 layers of fused metal but doesn't appear to have an applied rim, right?


also, since the construction of these pots consisted of thin fused sheets of silver/copper/silver which was cut stamped and moulded together, are these items rather light in weight and "flexible" as opposed to rigid in the body and thus subject to easily being dented?

Wonderful pics thank you again...Hilda

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burwoodhall

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Registered: Sep 2006

iconnumber posted 10-01-2006 01:19 PM     Click Here to See the Profile for burwoodhall     Edit/Delete Message   Reply w/Quote
PS: The silver mounts that attach to the wooden handles are ornate and lovely on the pitcher, are they cast sterling silver or are they also fused plate. I am wondering how sturdy that would that be if they are just thin OSP soldered onto a pot?
Thank you again..Hilda

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swarter
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iconnumber posted 10-01-2006 06:29 PM     Click Here to See the Profile for swarter     Edit/Delete Message   Reply w/Quote
I have not compared like objects, but OSP pieces are not particularly light, as the metal sandwich is probably thicker than the metal used in most pure silver objects, but the amount of silver put into a solid silver object is determined by the maker, perhaps based on how much the buyer is willing to pay. The thickness of OSP was supposedly more or less standardized by the technology, although I believe the thickness of the metals changed as the technology improved.

The ferrules used to attach the handles are not hallmarked, so they were probably not solid silver, although small silver objects could escape the hallmarking. They are shaped and not cast.

The tip of the spout does not show the copper edge - it probably has a layer of silver along the edge, although it is not visible as such. The "sandwich" is usually visible, as it is on both of these pieces, along the bottom of the foot portion where it contacts the table surface and wears as a result.

[This message has been edited by swarter (edited 10-01-2006).]

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Kimo

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iconnumber posted 10-02-2006 11:42 AM     Click Here to See the Profile for Kimo     Edit/Delete Message   Reply w/Quote
In general, layering of sheets of metal will normally create a stronger, stiffer material than something made of a single material. It is kind of like a plywood board is stronger and stiffer than an equal thickness board made of solid wood.

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swarter
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iconnumber posted 10-04-2006 01:07 PM     Click Here to See the Profile for swarter     Edit/Delete Message   Reply w/Quote
This thread, Questions about old Sheffield Plate, should be of interest, as it contains additional information about OSP.

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