Electrolysis - A Superior Cleaning Process. Updated October Based on experience, recent discoveries and feedback from internet friends. Latest additions :. Hydrochloric Acid in car batteries.
You will need to register before you can post: click the red register link or the register tab, above, right. Switch on supply and note current flow you should see some bubbling around the item you wish to clean - if not then the supply is connected incorrectly! Cuprous chlorides are very unstable mineral compounds. Electrolysis cleaning brass of the electrode used, allow the liquid to evapourate and dispose of the remaining debris in a responsible manner. As said many times, Electrolysis cleaning brass first before cleaning thin or hardened items or any component that is likely to be under considerable stress.
Bare ass twinks. Step 1: Materials
By schouw Follow. The downside aside from cost is, as I mentioned, the chemical byproducts - hexavalent chromium being the nastiest. Of course you can do it with re-bar, sheet metal or any similar material and it should work just fine. In fact, a member on here did a few axe heads awhile back using this method and they turned out fantastic in my Electrolysis cleaning brass. Those Stepmother slut came out great by the way, I am thinking of doing some of mine! In the end, you get tarnished aluminum, while the tarnish is removed from the brass, bronze or silver you started with. The difference is that the grime no longer sticks to the metal. I did this lightly each time i took them out, then used a little water and soft toothbrush, dipped them in water to rinse before repeating the electrolysis. This is a good way to clean up detailed items, where mechanical polishing could cause damage. To help the reaction run, we add salts as reactants, and use hot water to speed things Electrolysis cleaning brass. It is always good to have different options available. An Danske stripper adapter. Answer 1 year ago.
This is a easy way to electrochemically clean up brass, bronze and silver items that are badly tarnished.
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- Electrolysis is a simple and effective way to age brass quickly with minimal effort.
- This is a easy way to electrochemically clean up brass, bronze and silver items that are badly tarnished.
Toggle navigation Swingley Development. The book is by H. Plenderleith and A. They say that there is no problem cleaning brass by electrolysis unless the brass contains some lead. If it does, the brass will become pitted. The obvious problem is: How is anybody to know whether the brass contains lead?
I suppose you could dip a small corner of the piece into the bath and watch it over a short time. If it gets clean without pitting, then go ahead with the whole item.
Brass as well as bronze is always an alloy. When you electroclean an alloy, one metal can leave the surface before another, and can result in a frosted or pitted effect. It depends on how "active" the respective metals are. It makes sense that lead in the mix would be a worse case.
I have tried electrocleaning brass in the past and had pitting problems every time. I ignored them and tried for myself I found a user Stanley that badly needed electrocuting. One of the brass adjustment nuts is captive unless you remove the pins that hold the thing together.
I didn't want to wreck the plane, by either taking it apart or by pitting the knob, so I did a test first. In that test the brass didn't get clean, it got tarnished. But it also didn't get pitted, and the iron lost its rust as expected. I decided the damage from electrocuting the with the brass nut in place was likely to be less than the damage I'd create by trying to take the plane apart, so I just went for it and electocuted the plane.
The plane was in the bath for probably 4 hours 2 sessions in consecutive days , and the brass knob didn't have any pitting, although it was tarnished. The electrolysis loosened the adjuster from the underlying rust and made it very easy to turn. Unfortunately there are some places on a I just can't reach to scrub them with a scotchbrite pad, but I think I've cleaned it off enough to use it.
On a side note, does anyone have any good suggestions for removing the gunk after electrolysis in impossible to reach places? Just some personal experiences, I hope they help. In my experience, you definitely won't clean the brass with electrolysis, but if you want to clean the rest of the piece, it probably won't damage the brass too badly.
Lead is was? I dunno what requirements casting might impose: my experinece is limited to the machine shop. It seems to me that one easy way around this problem is to "mask" any part you don't want exposed to electrolysis or the alkaline solution itself.
The easiest way would be to cover the brass or whatever with a coat of vasoline. Vasoline petrolatum is basically half-way on the thickness scale between mineral spirits and paraffin wax - and all three are essentially the same stuff alkanes. Vasoline doesn't dissolve in water, doesn't conduct electricity, and wipes off leaving no nasty residue and will clean up completely with mineral spirits.
No, I haven't tried this myself, but I'm pretty confident it would work. So, someone with a rusted brass-backed saw can run the experiment: cover the back with vasoline and electrocute away.
Then report back to the porch with details. Heck, in theory you could cover the entire handle of a saw in vasoline and derust the saw without removing the wood!
Regards, Don Berry Thomas E. In experimenting, I've cleaned up some hardened grease covered tools that cleaned up just fine. Have also cleaned up some paint and glue covered chisels and planes that solvents and strippers had no effect. Would suggest that in using your method, watch it closely and often. I think the effervescent action of the breakdown of water into hydrogen and oxygen would get under any protective coverings.
I like electrolysis because it is forgiving to the iron or steel content of the tool only if I forget to remove the tool in time. Paint, japanning and other finishes, however, suffer. Trevor cites a conservator's refererence that confirms the observations of several galoots: some brass gets pitted when you're using electrolysis to remove rust from iron Regards, Don Berry.
Don My experience has been that if emersed long enough, the electrolysis removes dirt, grease, oil, paint, glue, etc.
It has probably been laying on the sea floor for decades, and in addition to the tarnishing, it is encrusted in the carbonate shells of marine organisms and other forms of grime. For a high polish use something like Brasso or any proprietary metal polish and cardboard - ideally corrugated box stuff. There are safety precautions that need to be taken and i feel researching and learning is the best way to do things. It goes on the negative pole of the AC adapter. On the forth picture I have simply rubbed the grime of under running water with my fingers, and on the last picture, I have removed the last of it with a scrubbing sponge to reveal a nice and shiny bronze handle.
Electrolysis cleaning brass. Step 1: Materials
Cleaning Brass by Electrolysis
The term does not imply a valence state as does cupric-divalent copper or cuprous-monovalent copper. The cupreous metals are relatively noble metals that frequently survive adverse conditions, including long submersions in salt water that will often completely oxidize iron.
Cupreous metals react with the environment to form similar alteration products, such as cuprous chloride CuCl , cupric chloride CuCl 2 , cuprous oxide Cu 2 O , and the aesthetically pleasing green- and blue-colored cupric carbonates, malachite [Cu 2 OH 2 CO 3 ], and azurite [Cu 3 OH 2 CO 3 2 ] Gettens The first step in the electrochemical corrosion of copper and copper alloys is the production of cuprous ions.
These, in turn, combine with the chloride in the sea water to form cuprous chloride as a major component of the corrosion layer:. Cuprous chlorides are very unstable mineral compounds. When cupreous objects that contain cuprous chlorides are recovered and exposed to air, they inevitably continue to corrode chemically by a process in which cuprous chlorides in the presence of moisture and oxygen are hydrolyzed to form hydrochloric acid and basic cupric chloride Oddy and Hughes :.
The reactions continue until no metal remains. This chemical corrosion process is commonly referred to as 'bronze disease. If the chemical action of the chlorides is not inhibited, cupreous objects will self-destruct over time.
Copper objects in sea water are also converted to cuprous and cupric sulfide Cu 2 S and CuS by the action of sulfate-reducing bacteria Gettens ; North and MacLeod In anaerobic environments, the copper sulfide products are usually in the lowest oxidation state, as are the ferrous sulfides and silver sulfides. After recovery and exposure to oxygen, the cuprous sulfides undergo subsequent oxidation to a higher oxidation state, i.
The whole chemical reaction generally proceeds along the same lines as those described earlier for iron. Upon removal from a marine encrustation, copper and cupreous artifacts are inevitably covered with varying thicknesses of a black powdery layer of copper sulfide that imparts an unpleasing appearance. The stable copper sulfide layer does not adversely affect the object after recovery from the sea as do copper chlorides; copper sulfides only discolor the copper, imparting an unnatural appearance to the metal, and are easily removed with commercial cleaning solvents, formic acid, or citric acid.
See North and MacLeod  for a detailed discussion of the corrosion of copper, bronze, and brass in a marine environment. Three effective chemical treatments are discussed below.
Consult the bibliography for further information. In some instances, it is necessary to mechanically remove gross encrustation and corrosion products from the artifact to reveal the preserved surface of the metal. This step is facilitated for sea-recovered cupreous objects because the marine encrustation will form a cleavage line between the original metallic surface and the encrustation.
When the artifacts are removed from gross encrustation, superficial encrustation is often deliberately left adhering to the surface of the artifact due to the fragility of the artifact or to avoid marring its surface. Careful mechanical cleaning and rinsing in water may be all that is required to remove this remaining superficial encrustation. In other cases, all adhering encrustation can be removed by soaking the object in percent citric acid with percent thiourea added as an inhibitor to prevent metal etching Plenderleith and Torraca ; Pearson ; North Citric acid should be used cautiously, as it can dissolve cupric and cuprous compounds within the artifact.
The artifact is completely submerged in the solution until the encrustation is removed. This may require an hour to several days, during which time the solution should be stirred to keep the acid concentration evenly distributed.
When a specimen is very thin, fragile, has fine detail, or is nearly or completely mineralized, any acid treatment may be too severe. In these cases, the artifact can be soaked in a percent solution of sodium hexametaphosphate Plenderleith and Werner to convert the insoluble calcium and magnesium salts in the encrustation to soluble salts, which can be subsequently washed away.
Following any necessary preliminary treatment, the conservation of chloride-contaminated cupreous objects requires that the adverse chemical action of the chloride be prevented. This can be accomplished by:. The first three alternatives can remove cuprous chlorides and reduce some of the corrosion products back to a metallic state; however, they are best used only on objects with a metallic core.
If carefully applied, these treatments will stabilize the object and maintain a form approximating its original, uncorroded appearance. If misapplied, they can strip the corrosion layer down to the remaining metal core.
Jedrzejewska draws attention to the fact that stripping, especially by electrolysis, may destroy significant archaeological data such as tool marks, engraved lines, and decorative elements, as well as alter the original shape of the object.
For these reasons, the corrosion layers of any metal artifact should never be indiscriminately removed. The treatment should strive to preserve corrosion layers in situ through very controlled electrolytic reduction or alkaline dithionite treatment.
The chemical techniques described do not strip the corrosion layer. Rinsing in a sodium sesquicarbonate solution removes the cuprous chlorides from the artifact, while benzotriazole and silver oxide seal the cuprous chlorides from the atmosphere. The chemical treatments are applicable to substantial objects as well as to completely mineralized pieces. It is generally regarded as an obsolete technique, except under certain circumstances already mentioned in the section on the galvanic cleaning of iron.
Either 2 percent sodium hydroxide or 5 percemt sodium carbonate can be used for the electrolyte. A mild steel anode can be used, but Type stainless steel or platinized titanium is required if formic acid is used as the electrolyte.
The same electrolytic setups described for iron or for silver below are used. Precise data concerning optimum current densities for cupreous artefacts are not available. Plenderleith and Werner state that the current density should not be allowed to fall below 0.
Keel states that a current density above 0. Along these same lines, Pearson correctly observes that care must be taken when electrolytically cleaning marine-recovered mineralized bronze in order to prevent damage to the artifact surface by the evolution of hydrogen gas.
Current densities, both within and in excess of the given ranges above, are commonly applied to different cupreous objects.
In general, the same procedures regarding current density that are described for the treatment of iron apply to the treatment of cupreous artifacts. The main variations in treatment involve the fact that the duration of electrolysis for chloride- contaminated cupreous objects is significantly shorter than that for comparable iron objects.
Small cupreous artifacts, such as coins, require only a couple of hours in electrolysis, while larger cupreous specimens, such as cannons, may require several months.
Since then, it has also been found to be effective on cupreous objects. A complete description of the treatment can be found in the file on silver. Alkaline dithionite treatment will destroy any patina on the surface of the cupreous object, but it effectively removes the bulk of the chlorides in the shortest period of time; further, it reduces some of the copper corrosion products back to metal. There are three different chemical treatments available that are used to stabilize the artifacts while leaving the corrosion layers intact: treatment with sodium sesquicarbonate, with sodium carbonate, or with benzotriazole.
A summary of cupreous conservation techniques can be found here. When bronzes or other alloys of copper are placed in a 5 percent solution of sodium sesquicarbonate, the hydroxyl ions of the alkaline solution react chemically with the insoluble cuprous chlorides to form cuprous oxide and neutralize any hydrochloric acid by-product formed by hydrolysis to produce soluble sodium chlorides Organ b; Oddy and Hughes ; Plenderleith and Werner The chlorides are removed each time the solution is changed.
Successive rinses continue until the chlorides are removed. The object is then rinsed in several baths of de-ionized water until the pH of the last bath is neutral. In practice, the superficial corrosion products are mechanically removed from the metal objects prior to putting objects in successive baths of 5 percent sodium sesquicarbonate.
For the initial baths, the sodium sesquicarbonate is mixed with tap water; de-ionized water is used for subsequent baths. If the chloride contamination is extensive, baths prepared with tap water can be used until the chloride level in the solution approximates the chloride level of standard tap water.
De-ionized water is then substituted. This procedure is very economical when processing objects that require months of treatment. Initially, the baths are changed weekly; as the duration of treatment progresses, the interval between bath changes is extended. Monitoring the chloride level by the quantitative mercuric nitrate test enables the conservator to determine precisely how often to change the solution.
In lieu of a quantitative chloride test, the qualitative silver nitrate test can be used to determine when the solution is free of chlorides. The cleaning process is slow and may require months and, in some cases, even years. The sodium sesquicarbonate treatment is often used by conservators because, unlike other cleaning treatments, it does not remove the green patina on the surface of cupreous objects.
This treatment may encourage the formation of blue-green malachite deposits on the surface of the objects, which will intensify the color of the patina. If malachite deposit formations occur during treatment, the object should be removed from the solution and the deposit brushed off. On some bronze pieces, this treatment will result in a blackening of the surface, which obscures the original green patina and is difficult to remove.
This blackening is attributed to the formation of black copper oxide and appears to be an inherent characteristic in some cupreous alloys. Sodium Carbonate Rinses The sodium sesquicarbonate treatment outlined above has been the standard treatment for fragile cupreous artifacts with chloride contamination and for artifacts that have a patina that is desirable to preserve.
In practice, however, conservators find that the treatment often enhances the patina, making it much bluer in appearance.
In other examples, it has considerably darkened or blackened the patina. First, the treatment may require well over a year before all the cuprous chloride has been converted. It has been shown that sodium sesquicarbonate a double carbonate forms a complex ion with copper and therefore preferentially removes copper from the remaining metal Weisser This can be potentially structurally damaging over a prolonged period. It has also been shown that a mixture of carbonates, including chalconatronite, a blue-green hydrated sodium copper carbonate forms over the patina and also seems to replace other copper salts within the patina Horie and Vint This creates a color change from malachite green to blue-green, which in many cases is undesirable.
In the objects the author has examined the blue-green color can be found in cross section from the outer corrosion crust extending down to the metal substratum. The stabilization of actively corroding archaeological bronzes remains a difficult problem for conservators. At the present time no known treatment can be called ideal. Bronzes which cannot be stabilized by this treatment should be stored or displayed in a low relative humidity environment.
Weisser suggests that if previous treatments with BTA have not been successful, the objects can be treated with 5 percent sodium carbonate in distilled water.
The sodium carbonate removes the cuprous chlorides and neutralizes the hydrochloric acid in the pits. Sodium carbonate, unlike sodium sesquicarbonate, which is a double carbonate and acts as a complexing agent with copper, reacts relatively slowly with copper metal. Still, in come cases, slight alterations in the color of the patina can occur. Benzotriazole The use of benzotriazole BTA has become a standard element in the conservation of cupreous metals.
BTA follows any stabilization process and precedes any final sealant. In some cases, it can be a single treatment unto itself. When marine cupreous objects are conserved, however, BTA is usually used in addition to some other treatment, such as electrolytic reduction or alkaline rinses, which remove the bulk of the chlorides.
For artifacts from a fresh water site, it may be the only treatment required. Treatment with BTA does not remove the cuprous chloride from the artifact; rather, it forms a barrier between the cuprous chloride and moisture of the atmosphere. In this method of cleaning Madsen ; Plenderleith and Werner , the benzotriazole forms an insoluble, complex compound with cupric ions.
The precipitation of this insoluble complex over the cuprous chloride forms a barrier against any moisture that could activate the cuprous chloride and cause bronze disease. Tests at the British Museum Plenderleith and Werner indicate that if active bronze disease is present, all attempts to stabilize the object with BTA may fail due to the widespread distribution of cuprous chloride in the corrosion layers.