Best Way to Clean a Brass Valve?

Depending on your resources, soda blasting or dry ice blasting would work.

Mechanical buffing, depending on the detail of the casting, might work, too.

Brasso? Wadpol? For the final polish.

Don't have the access to soda or dry ice blasting unfortunately.

Have been doing the mechanical buffing but am still left with lots of hard to get at places, which is where this 2-3mm build up is- From the little I've seen (net wise) it looks as if an acid may be the answer.

I'm hedging towards very hot water and bleach as we don't really have a place to deal with acid in any quantities over about a cup full.

If you cannot get dry ice to blast it, then try to find a supplier of plastic bead blasting powder. This stuf can be applied with a conventional sand blasting attachment on an air compressor.

Build yourself a small cabinet with perspex front so you can collect the plastic beads for re-use until the job is done.

Alternatively, can you dismantle the valve? You might then find that standard machining processes can be used to dress each surface of the valve.

Is the "patina" also on the external surface?

Sounds like it might have experienced sea water or sewage from the build-up you describe.

Have a think about thermal properties of the materials. It might be that by heating the valve (check for rubber seals etc) that the crust might have a different thermal expansion rate and may release at higher (or lower) temperature.

Do you have a picture or part number? Some local "friends" might be able to give me a hint to pass on.

One final question. Are you certain it's patina and not some poorly applied protective coating? I've seen some attempts to protect older components in situ (2m below ground level) using hand applied 2 part epoxy. Not a pretty outcome, but probably effective.

Will check with other Depts, may have bead blaster. Unfortunately can't get the valve fully dismantle nicely owing to some of the corrosive influence. So the blasting may not get all the areas.

The patina is almost everwhere except under whats left of the paint work. It is definitely NOT an applied protective coating

The (explosion? &) weather proof signal section has a label which says F.Bamford (Inst) LTD. Theres a serial & drg#. Nom Bore 3", Flow Switch-Tag No FSH 63010.

The main body has large site glasses (that have also taken deposits of the 'patina') but I can not find any reference to manufacture on any of the castings.

having trouble with getting a camera for a pic.

Sounds like it might have experienced sea water or sewage from the build-up you describe.

One would hope that this valve was not used for sea water/black-water operations. One should never use 60/40 or 70/30 brasses on any sea water systems as they do last very long and can be outright dangerous if used in marine environments, as the sea water leaches the zinc out of the copper/zinc matrix and leaves you a porous copper components of the valve.

Naval brass (62% Cu, 36,75% Zn and 1,25% Sn) is okay for for valve spindles, etc., as the small percentage of tin prevents the leaching of the zinc.

For sea water applications your best valves have marine grade bronzes for for the body and lid castings and super alloy components (monel), i.e. spindles, discs, seats and split pins. Although stainless steel components can be used the previous mentioned materials are preferred.

Maybe blast it with a mildly aggressive medium such as walnut shells?

If it's anything like the green build up we used to get on our effluent line valves, steam cleaning may work. Failing that you will need something like walnut shells to shift it.

For some possible leads, google "F Bamford Valves" and see what comes up. Compressors and vandal proof items plus marine flowmeters and such.

A valve with a sight glass may have been part of a flowmeter.

Been on the site - didn't think to go there- Your right, it is a flowmeter - but no clues to best ways to clean - Found out our automotive section has a small blasting unit so will wander over next week and give it a run - I've got a number of bodies that I can test the blasting on.

....all mimsy were the borrogoves, and the mome rath outgrabe. Etc, etc.

You might try dilute hydrochloric or dilute caustic soda, but either might attack the zinc in the brass so I'd do a spot test first. Anything with ammonia in is likely to attack the copper.

Not trying to be funny, but if you can't tell a non-return valve from a flowmeter, should you really be doing training?

Cheers......Codey

It is covered in green patina. It appears as if this corrosive process has interacted with the product it carried and has built in to large chunks of green stuff.

Try to confirm the compound which made-up the green stuff, it may be cuprous oxide or copper sulphate (if interacted with sulphur). Then to get compatible cleaning agent which reacts with it.

Simply immerse the item in a proprietary brand of cola overnight. Rinse to drain with water afterwards. Hey, Presto!

In Perth too!

I keep a litre of flat 'Coke ' on hand for just such jobs. Easy as pie.

I question your use of it as a training aid in what type of training or course you are giving. The condition of the valve is educational. To make it shine and look new will not educate them on material choice or chemical effect on material better then to see the results first hand.

Primarily the item is more for this is what ones is and this is how it works. The fact that it has had a corrosive attack is secondary - But it is useful also. On similar bent to what your talking about, a section of another of the flow valves has had a 'neat' piece of corrosive attack - When I was dismantling it two brass studs tore out of their location in such a manner that both of them ended up with needle point ends. The result was so neat and clean that one lecturer wanted to know why the unit had needle valves fitted - and those we are keeping along with the section they came from with a majority of the 'green' material.

by the by re cleaning I'm not concerned if I get the brass shiny I am just wanting to clean it up more for a 'health' aspect than prettiness.

Heloise, in the USA newspapers, says that vinegar will do lots of things. It's cheap enough to give it a try.

A paste of vinegar and table salt cleans copper and most copper alloys quite well. It is somewhat more aggressive than cola but it's also relatively non-toxic, although the stuff you clean off of this valve may not be. This combination is mildly abrasive, which hastens the cleaning process. When you are finished it will be clean but not polished. Brasso will brighten it, but be prepared to remove the polish residues with a wooden toothpick.

I cleaned a telescope I dragged out of a swamp with vinegar and salt. Worked very well.

I don't like ammonia...though it works well, it smells awful.

http://www.finishing.com/#archives may provide you a most appropriate solution.

Good luck.

try toothpaste...

try covering in HP sauce and leave overnight, it is mildly acidic and cleans brass great