Finishing of Kenrick 19th Century Cast Iron

A. Hi Emelia. This isn't an antiquing, appraisal, authentication service, but we'll need at least a photo before a reader can help. E-mail it to mooney@finishing.com. Thanks!

Luck & Regards,

A. In looking at The Chemical Formulary", Volume 5, Chemical Publishing Co., Inc, 1941, Brooklyn, New York [on eBay , Amazon, AbeBooks affil links] it seemed to me that the original brown finish could be:

• antiqued bronze plating ( electrolytically plate a clean iron surface with a copper-tin alloy, and dip in something which forms a brown surface (perhaps a sulfur compound) or they could have been bright bronze which weathered to the brown finish.
• an organic coating. The one I would have you try first is British Patent # 494,963:
  Heat tung oil ⇦this on eBay or Amazon [affil links] 200 gals. for 15-20 min. at 340 °C. until it approaches gelatinous stage and then add sardine oil 20 gal. cool and then add whale oil 60 gal., sardine oil 200 gal. and 1/2 percent by volume of manganese cobalt drier. (If you get this on your clothes, don't bother going home)
• Maybe a cadmium coating with some kind of post treatment, but you don't want to use this one, even if it is original. Cadmium is too poisonous, as it turns out.

So I think an antique bronze or bright bronze from a modern electroplating bath may be the best bet, depending upon how valuable these items are. I bet it would cost you US $20 or $30 a piece to deoxidize, strip, buff, plate, and antique these things to a nice finish.

Being into documentation, I would recommend that you describe the proper treatment for restoring the pieces, to try to avoid someone dissolving them away in the first pickle bath in which they are immersed. I'm not saying platers are stupid, but this kind of thing has happened before. Besides, do a good story on this, and we will publish your article on these pages. A scientific study of restorations makes for the most interesting reading. You know; before and after pictures, a photo op for some laboratory in a big corporation, charts and tables, a picture of you in some old library, blowing the dust off of some tome, it breaks up the dull day.

I would try to find some interested metallurgist in a materials lab who might do an Auger analysis, or somehow find out the composition of the coating and base metal. Armed with an analysis, you might get some plating consultant to write up the procedure to replate them.

A. Hi J.
Please test it with a magnet because my first guess would have been that it might be cast brass or bronze rather than cast iron, which would make the brown color less unusual.
Luck & Regards,


Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. The thing is, Neil, that the original enamel was probably porcelain enamel, applied something like how glass is made--with a ceramic frit that is melted and fused at extremely high temperature (thousands of degrees) onto the cast iron. You can't do that, sorry, so you're restricted to paint (which just isn't as good); but you could look up "baththub refitters" for forms that do such painting. If you want to do it yourself, thread 22525, "Bathtub repainting/refinishing" is about successes and failures at this enterprise.

A. To my knowledge the finish on the "standard" Kenrick door knocker is not documented but porcelain enamel fills the bill, both from my observations of well preserved knockers and because its "hardness" is a real advantage. Whatever the finish used it was essential to prevent "rusting" in the English climate. I don't believe it was a "clear" lacquer or even a "coloured" lacquer [gold, bronze, etc.], which while the latter was used for brass microscopes, magic lantern lenses, etc., it would not able to survive the travails of the weather facing the outdoor knocker. With regard to Kenrick door knockers 2 additional finishes were offered in some cases, namely Berlin Black and French Bronze, at six pence extra [nearly an 30% more than the "base" price for the knocker]. This latter French Bronze finish is not uncommonly seen on late 19th century knockers causing vendors to refer to them as "brass". Incidentally, a local company [?], Porter's Original Paints, now supply a similar product called Liquid Bronze, which can be buffed to a similar finish. On some knockers a true brass component could be ordered -- e.g., the door plate mount --- but given the different moulding/casting procedures required for the separate pieces in cast iron and bronze [different chillers for example], the added expense was substantial. For example Kenrick No. 365 had a base price of 1 shilling and three pence but this became 5 shillings and six pence if supplied with just a brass centre rather than the cheaper cast iron.

Finally, sorry to be so boring, but not all cast iron is the same formulation with a higher carbon content [and hence more malleability for superb casting] was used on door knockers [given their "first impression" status] compared with cast iron boot scrapers. But I could be wrong. It would be important knowledge to have as wherever possible the original finish should be preserved.

But for heavily rusted items or those with multiple coats of paint I use a caustic paint-stripper to remove most paint [not always effective, but I haven't used a heat gun ⇦this on eBay or Amazon [affil links] , yet] then any paint remaining using a brass wire brush ⇦this on eBay or Amazon [affil links] . The final finishing I do with a 3000 Dremel ⇦this on eBay or Amazon [affil links] and a Dremel 428 steel wire brush, and a final buff with a cotton Dremel brush. I like to feel that this is how the knocker looked coming out of the mould, so I do nothing more, just keep them free of moisture [hygroscopic crystals] in a display cabinet. Who says collectors are obsessive?

Hi again. Just an update on my previous answer. I supported Ted Mooney's comment about porcelain enameling as a likely finish on cast iron products of the 19th century. I now have some harder evidence to support him. In 1846 Timothy Kenrick of Kenrick and Sons at the West Bromwich Foundry was granted a patent for "the glazing and enameling of cast iron which led to investment and the growth of home and overseas sales"

I think all in all dear friends, that's a QED.

A. Hi Ross. It doesn't look to me like it needs any restoration; I think the recessed areas are supposed to be blackish. A magnet will quickly tell you whether it's cast iron or cast brass.

On the one hand, 'knockoff' can mean a recently made item built by a reputable outfit but in the general style of older traditional items; and on the other hand it can mean "counterfeit". Reputable outfits certainly would not cast the word "Kenrick" into their items; and, although your item is very beautiful and you should enjoy it, I doubt that it is so valuable as to inspire counterfeiting ... so I'd say it's almost surely real.

Regards,

A. If you want all the answers on EVERYTHING about Kenrick door knockers and more, buy or read my 2019 book of 315 pages titled "The Art of the Door Knocker".

? Hi. That's fine Garry, but how does one do that? I'm not seeing your book available for sale anywhere, and WorldCat shows it available only in two libraries in Australia.

Luck & Regards,

A. My fault Ted
The book has door knockers and full catalogues of Kenrick and others plus lots more but focuses on Kenrick. It cost me $40 just to print locally and postage to UK costs 50 GBP and that's the problem. I am a true scientist so the book is right up to the mark. Go to Garry Scroop on the internet to find my sorry sad tale.
Garry

A. Hi Ross

I have 2 examples of the cast iron versions of AKS door knocker No. 313. Both are 22.5 cm or 8-3/4 inches long and 9 cm or 3-1/2 inches at the widest part. The first example I have is what I presume to be an earlier casting, where the only foundry mark is the number '313' which is 'engraved' vertically on the reverse of the door plate at the top end towards the right edge, but nothing else.

The second example I have has 2 foundry marks. Firstly, on the reverse of the door plate are the same markings as on your brass version, namely KENRICK 'embossed' vertically at the top and 313 'engraved' horizontally at the bottom of the door plate. Secondly, on the knocker arm, on the left side of the bottom 'loop', viewed from the back, again 'embossed' is KENRICK & SON(S). I have seen your brass version and there is good evidence that a few of the longer lasting AKS patterns were offered in brass after 1900, and yours is almost certainly original. A brass polish with a tooth brush and then buffed is perfectly acceptable, but to me they never appear as 'sharp' as the cast iron versions. Where I have used the terms 'engraved' and 'embossed'. I am of course referring to how the original casting appears to the modern viewer at this stage. The cast iron version of AKS door knocker 313 weighed 844 gm and cost 1/2d in 1899. All in my book.