Hi folks, I just aquired a Tilley Guardsman in chrome which I have never seen before. This is heavily tarnished and I remember on a previous thread there was mention of a citric acid bath recipe. Does anyone know the concentration required and the length of time immersed? Also the cage is heavily rusted. Are these still available, or is there another solution to this common problem. Many thanks D.
The Guardsmans tank will be plated in Speculum, not Chrome. I have not used a citric acid bath on Chrome or Speculum, only on Nickel plate on Brass and bare Brass. Citric acid will leach Zinc out of the Brass, so long immersion periods are bad. Anyway for Nickel... For Nickel plate I use a B&Q bucket full of hot water and add about one or two tablespoons of citric acid crystals, I guess it depends on how fast you work. Wearing Nitrile glove and safety glasses I take each part needing treat and dunk it and immediately get to work with a stiff toothbrush or a non-scratch sponge and clean it until I'm satisfied that polish will do the rest of the job. Once I'm finished with a part it goes in a bucket of clean water and is then rinsed off. If the Nickel plating has been physically damaged it may lift revealing some of the Copper plate underneath, but only in tiny patches that are not noticeable. There is a lot more on using citric acid to clean unplated Brass over at Classic Camp Stoves. You could also try the advanced search here, just remember to set the 'Match posts made' option from 'the past year' to 'anytime' If the cage is badly corroded then replacing it is the simplest option, there are always a few on ebay and I'm sure some people here might have some in their parts piles.
I have seen that longer exposure to citric acid will make the plating on a guardsman fount go a dull blue-grey colour which does not polish off. A wipe-down with warm citric solution on a sponge, thereafter neutralized with warm soapy water is safe enough. You can also add a few drops of dish washing liquid to the citric acid solution. But try a good kitchen cleaner like Handy Andy beforehand to remove any dirt and oiliness from the metal. By the way, citric also removes rust from steel very effectively. I soak rusty bails and globe cages for a few days sometimes and then clean up with a scouring pad and/or steel wool. Note that any plating on the steel will be gone!
Thanks folks, I'm glad I picked your brains before going ahead!! And what is speculum anyway? I tried putting it in a Google search but all that comes up is gyneacological tools.
Speculum is what Tilley called the plating on post WW2 lamps. Quite what it is remains a mystery but one formula for speculum is:- 16.5 parts tin, 32 parts copper, 4 parts brass, 1.25 parts arsenic. As some sort of confirmation, the Oxford Dictionary defines Speculum as “a mirror usually of polished metal, especially in a reflecting telescope. Also Speculum metal as “An alloy of copper and tin used as a mirror”. ::Neil::
Hi Neil, I'd be interested to know what methods you use for cleaning nickel plated brass. So far the acid bath works for me as I like to remove the oxides that have built up on the surface as gently as possible without having to resort to purely mechanical means such as polishing. Thanks, Ellie
HD While awaiting Neil's response... For lamp tanks I usually use, these days, a proprietary brand of engine cleaner that is detergent based. I find that vinegar and citric acid are often a bit harsh on well worn speculum or nickel. The advantage of using a detergent-based cleaner is that you don't have to worry about emersing the whole tank and letting it fill up. I'll find the original container for the engine cleaner and post its composition. If the inside of the tank is really cruddy, I use "Marine Clean" - which I also use as a last resort for caked-on organic residue anywhere on a lamp or stove. I usually use 1:3 vinegar:water for the brass bits (burner etc), being careful not to leave in for too long. Cheers Tony
Thanks Tony, Yes, it would be interesting to know what is in that cleaner you use. I already use marine clean those tanks that have the putrid green gunge in them. HD
I generally just use a modern kitchen cleaner and then maybe Autosol. A lot of lamps don't have a great deal of nickel so you can't get too aggressive or you start to show the brass. I tend to be a pretty idle old git so never bother to get a mirror shine. Clean will mostly do it for me. ::Neil::
Caustic Soda to clean really gungy tanks (insides of). A fairly weak solution will do... Gunk/Jizer for lightly dirty tanks
Speculum metal: https://en.m.wikipedia.org/wiki/Speculum_metal If you google "speculum plating" you can find whole books about it. Tony
Before I came across it here I was only familiar with it as an alloy used in the mirrors some of the early large astronomical telescopes. I have no idea why Tilley used it or what is actually in their mystery alloy. My best guess is that because it is a single step plating process that it offered some kind of cost saving over a three stage copper, nickel and chromium plate.
Hi, A good way to clear tarnish from Speculum plated tanks, is to use a product called Bar Keepers Friend. It's a powder and I just daub it onto bundles of 0000 wire wool, but scuff the wool out first, taking the edges off; that way, you can without that much pressure being applied, safely reveal most of the speculum, a new or as good as, without baring the copper under plate. It's also very good, used in the same way to make glass's or globes, that are moderately scratched or lightly scorched; back looking much clearer and shinier, it's still surprising to me, just how good a product it is ! It can be found in eBay, so I buy 4 bottles at once and am good for a year or so easy. Jon .
... Well it was originally oxalic acid; but what appears on the market today is citric acid: http://www.barkeepersfriend.com.au/pdf/MSDS_Bar%20Keepers%20Friend%20Cleanser%20&%20Polish_2015.pdf Tony
... although the "Bar Keepers Friend" spray foam contains both citric acid and oxalic acid; http://www.barkeepersfriend.com.au/pdf/BKF-Spray-Foam-Cleaner-SDS.pdf Cheers Tony
Well after all that, I used Neil's method and started with Gumption Kitchen cleaner and a stiff brush. Then some vigorous and lengthy rubbing with Autosol. Where the speculum had lifted, this was rubbed off to reveal brass freckles, only seen on close inspection. When the citric acid arrived I risked the rest of the bits,ie the cock, pump knob and collar with a 20 miniute immersion, before a polish with Autosol and this didn't seem to do any harm. The cage is still in soak in the acid, this will be followed with a rubdown and a spray of barbeque silver paint. below some before and after pictures.
Neil, Tony, Tacho + HD . . . I've been using that Barkeepers for yonks now and swear by it, it's really good at giving a uniform "all over" skin or metal detox, particularly if it's used with the four zero wool; it's the step before, either moving on to the Solvo autosol/ soft rag . . or the usual final Brasso rub up. Marvellous powder it is, a "must have" but keep the marigolds on . . . Ace on scratched glass too, the finer ones, ect . . . . Jon .
You can also get Barkeepers as a liquid. We stock both types in B&Q. I assume it is the same stuff in a liquid carrier. Not tried either yet but I will. ::Neil::
Thanks for your advice everyone, it hasn't turned out too bad after all. Barbecue silver was the only solution for a badly corroded cage but personally I would have prefered a darker silver. The control knob was too hard to remove so left well alone. Ready to fire up tonight for the first time in decades.
That's a lovely job and spritely with it, a very clean cage re-spray also; shifting years of rust completely from Tilley cages, can really be a struggle. Was it done the hard way, . . . or ? Jon .
Thanks Neil, I'd not known of the liquid BKF, I'll see if there's some in Hudd's branch ?! It'll be interesting to see if through its use, any of the "grist' stages can be cut back on; though I'd imagine it only giving a good result, if it's applied with a soft cloth. Ta, Jon.
Thanks Jon,The cage was soaking for two days in the citric acid bath after a couple of members suggested it and this got the worst off. Then a wire wheel on the drill did the rest down to clean steel. After the respray a couple of hours in the oven at low heat to speed up the curing process and hey presto!! There is some pitting left by the corrosion but only visible very close up.
Ha ha, . . done the hard way then ! It does my bonce in within all the weld areas, so much so I put off doing them, but they have to be done sooner or later ! I find the the easiest way to get into the steel to steel joints, is to buy the very course wire wool (long job/ but worth it !) and unravel it all (or to a yard & a half, ect), then either plat it (too intense, most days ) or warp it into a strong enough wire rope; then grip the cage in the vice and do the obligatory back 'n forth okikoki ! It beats the neck ache of the "near too' finger crunching Brillo efforts & the above above method does work & is quicker; it's just remembering it smartly in time, umpteen jobs morphing/ where's the nearest Oasis, ect. I've some scans that need down sizing, re the sprucing up of cage frames . . . I'll add them later on; it might be a helpful idea, though a bit excessive ?! Oh, my ovens brand spank BTW, it just gets my food for now, but it'd be worth experimenting with a cheap market stall mini; testing on a dry boned fount first, just to see how the solder holds up, ect ? I'm on with some ATM and it's already turned into a quest again . . . searching for the Sun & a hand behind the back . . . . Jon .
