Hello all, How often do you feel some 'tediousness' in cleaning brass? And the tarnish comes back too soon? Need clear lacquer to preserve the finish after you're done with the polishing? Certainly not me..well, at least, not anymore. Here's a simple example of how I do it without elbow grease: The above shows the picture of a piece of highly tarnished brass tube. I'll dip it into my pail of 'witch's brew'. Its acidic but does not fume or cause severe burns if you accidentally get it on your hands. Note that I'm not wearing gloves. So I'm dipping part of it into the brew. Duration: just 10 seconds. Withdraw it from the brew. Note the difference? Its brightened but no reddish or pinkish copper on the surface. I rinsed it in cold running water. Wiped it dry with a piece of paper towel. Here's what it looks like after drying. Any fans of bare brass around? So, that's how easy it is for me to clean brass. The cleaned brass will not tarnish for a long time under normal atmospheric conditions. Is the above different from your usual routines on brass cleaning?
The stuff in the pail has been forgotten until today and left in my backyard for close to a year. Now I'm really having some trouble looking for the recipe (as usually the case for all my other things in the house). I only remembered brewing up some wash liquid to clean copper and brass. A little bit of both chemistry and perhaps alchemy I'd say. "Something that's not too aggressive or corrosive which is, easy enough to use in a non-industrial setup. Something that is fast-acting. I was trying to formulate one that wouldn't hurt the bare skin, as long as you don't leave it there for too long. Something that doesn't fume and corrode the surrounding stuffs like muriatic or nitric acids. Something that could completely clean brass without abrasion, and would clean it down to bare yellow or brass-coloured metal instead of leaving a red/pinkish copper hue on the surface. Something that you could leave your brass or copper in it for a few extra minutes without appreciable pitting and etching. Something that has a somewhat indefinite shelf life. Something that can be used without heating. Something that has a micro-polishing action on brass and copper. Something that'd leave a very thin and invisible film that'd protect the metal from atmospheric air and moisture and thus prevent tarnishing to some extents. Something that can be kept in cheap and readily available plastic containers(polyethylene or polypropylene, for example). Something that doesn't smell or fill the air with offensive odours. Something that is water-based, where excess or spills could be easily washed off. And most importantly for me, something that could greatly ease the job of cleaning brass/copper. I'll try to search around and see if I could find my own recipe. I hope I've not thrown it away because I simply couldn't recall the ingredients used. I'd post it here if its found.
Brilliant results - that sure would save some time compared to our normal methods. Hope you find the recipe...looks like it would be useful for all of us.
I'm not exactly certain but I think I might have found it. Looks like it ain't too friendly after all. I'm using it anyway. You can't simply dump the spent liquid into the drain. Here it is. Dissolve the following chemicals into eight(8) litres of de-ionized water: That's my dark red witch's brew. Here're the names of the ingredients: CrO3: Chromium Trioxide. H3BO3: Boric acid. Na2SO4: Sodium Sulphate. NaNO3: Sodium Nitrate.
Yes, something as effective as that would have been commercially available for years if there hadn't been any problems associated with its use by the general pleblic... Edit: Chromium trioxide - Wikipedia FYI - NFPA 'Fire Diamond' Blue (Health Hazard) 4 = Deadly Yellow (Reactivity) 2 = Violent Chemical Change White (Special Hazard) OX = Oxidiser (may ignite organic materials e.g. alcohols, fuels) on contact. On your own head be it!
I would not use anything with Chromium trioxide in, it is intended for use in industrial settings with engineering controls, i.e. not in your garage are home. Its used heavily in chrome plating application. I would be surprised if you could even buy it domestically. I'll stick to citric acid in my ultrasonic tank.
To be honest you can achieve similar results (UK only) with Harpic Max x10. You can make a bath to soak items in if it's diluted with water or you can use a sponge and apply it neat. The parts need to be rinsed in cold water afterwards to stop the corrosive action. I know that there's a similar product in the US because @Norman has some. The active ingredient is hydrochloric acid. Disposal after use might be an issue (or you can keep it in a plastic tub for future use) and gloves are strongly advised or it'll eat holes in your skin... probably!
Yeah. Thanks for the advise and concerns, guys. I knew about the dangers and risks associated with Chromium Trioxide. Simply one of the nastiest to be around if you're not careful. Its a proven carcinogen too. You sure wouldn't be able to buy it domestically, @Gary Waller. In fact, I actually synthesized it from Lead Chromate yellow pigment with concentrated sulphuric acid.(Both are nasties too). You're right, @David Shouksmith. Its truly as effective as I've demonstrated earlier. Simply as amazing as shown in the pictures. Everything done under 10 seconds. No tricks. Naturally, it comes with equally negative traits as well. No other acids that I know of (except nitric acid), could act as fast as this on brass and yet result in a brass or yellow-coloured surface on the piece. All other acids would preferentially corrode the zinc and produce a reddish or pinkish hue instead. Yes @presscall , some PPE would be required. Certainly not rubber gloves. Perhaps HDPE or PTFE gloves. Something that's resistant to a highly oxidizing acid. I have tested with hydrochloric acid too, @ColinG . Even at high (fuming) concentrations (its available here as a mosaic cleaner), its not a match for the 'witch's brew' in terms of speed and finish. Let me guess...you wouldn't want this stuff for Chrismas.
I figure the stuff I restore has typically 50-90 years of dirt and corrosion. Taking a day or two with citric acid to get it cleaned off seems to be in character for it. Hydrochloric acid--did that for a bit using "concrete etch" (alias muriatic acid). It certainly is fast but way too nasty to bother with. The fumes when mixed into water are brutal, nevermind a splash from the solution that inevitably finds the gap in your PPE. Chromium Trioxide? The SDS for that reads just like the one for methyl-ethyl-death! Mike.
You can still buy products containing hydrochloric acid domestically but not any that contains Chromium trioxide or chromic acid.
Some thoughts: the dark skin is an oxide of the metal involved (brass, copper) So to get it bright as shown, this skin is dissolved. Most oxides however protect the metal also. The clean look is more a cosmetic idea/look then functional cleaning of dirt. Overhere we have a product called DASTY sold as a de creaser and very effective for clening lamp parts. Another product is the anti calque cleaner for your batroom cleaning. Not completely harmless, don't sok it to long. But it works well.
I can imagine that trying to buy the ingredients for that concoction could well result in a 4am battering down of the front door and confrontation with the local armed response unit I'l stay with my trusty clock cleaning solutions.
Haha. Yeah. I believe only Chromium Trioxide is highly restricted due to its toxicity and carcinogeneity. The remaining stuffs are not particularly controlled but rarely sold to the public as they are not consumer products in any way. Nevetheless, I did not buy any of those. When properly treated with the concoction, brass will retain bright and tarnish-free for a considerable lenght of time. Even where its frequently wetted with water. And without lacquer too. Its both water and fuel resistant. I've never seen any product on the domestic market that works like it. Too bad its highly toxic.
Yes @WimVe , the dark patina and oxide film actually protects the underlying metal. Its natural passivation. Some of us prefer the classic patina look. Others prefer the bright new look. I have no preference. I love them both.
The very least I could do is to reduce the hexavalent CrO3 to a much less hazardous trivalent green chromic oxide. I believe its easily reduced(chemically). I think there's a product called Iron Out in powder form. Might contain some Sodium Sulphite or sort of, for the purpose. Or I'd just keep it contained in the drum at the backyard. I doubt anything much would happen if I simply flush it down the bowl.
Stick to the elbow grease. Much prefer to disassemble and clean a lamp with a beer in hand rather than be handling such chemicals. No need for it.
I might have guessed. Perhaps I'd just stick to the first two. Just a thought, similar stuffs might just be still in use in the industry, at least in developing countries where the regulations and enforcements on environment protection and safety are less emphasized.
