Cleaning Brass by Electrolysis

[Joe]

Oxalic acid - you can get it in loads of places.

Including rhubarb leaves.

- Joe

[Nick]

Oxalic acid - you can get it in loads of places.

Including rhubarb leaves.

Indeed, which is why you shouldn't eat them... you can extract oxalic acid from rhubarb leaves, however, its far cheaper and easier to buy it !

Here a photo of some oak French doors that were BLACK with stain as they are completely exposed to the prevailing winds & weather (we are on top of a hill) - I used oxalic acid gel to clean them.... (Osmo sell it as their "wood reviver" but I made my own [eventually!] - the door on the left has been brushed with Osmo UV 420 oil - the one on the right is after oxalic treatment but before oiling)

[dennishoy]

This appears hard work and electrolysis attacks the zinc element of the brass leading to surface discolouration (i.e. the copper begins to show through).

I use horolene concentrate from a supplier like this....

http://www.cousinsuk.com/catalog/7/1125/1350.aspx

I mix one part Horolene with seven parts water and use it again and again until it no longer works.
Immerse the item in warn solution for 10-15 minutes. Repeat until clean.

Horolene is just ammonium oxalate with a bit of green liquid soap added - you can make it easily from an oxalic acid solution - a teaspoon of oxalic acid crystals in a cup of warm water - plus a few ml of concentrated domestic ammonia solution and a couple of teaspoons of green liquid soap.

Soak for about 10 minutes - not more, rise thoroughly with distilled water, then methylated spirits, then dry with a hair dryer etc.

You can make a litre for well under a quid - Horolene is about 20 quid /litre

Oxalic acid is widely used for bleaching wood in cabinet making and restoration (removing stains from oak etc.) - you can get it in loads of places - I bought my last lot from a well known auction site... also used by bee-keepers as a safe treatment for varroa infestations...

Note that oxalic acid is toxic and you should avoid getting on your hands...

I get the impression there may be additional stuff in it.... I've tried a made-up oxalic acid solution a couple of times and it leeches the zinc from the brass leaving a 'coppery' surface stain which has to be removed by metal polish. Horolene doesn't exhibit this effect and leaves a nice, shiny brass finish (unless you forget and leave it in the cleaner overnight... Dohhh.). I bought a 5 litre can of Horolene a few years ago for £40 and am still using it. There is a newer alternative (called Horogrene ??) which has no ammonia or other unpleasant smell. I've not tried this, but read somewhere that the old stuff may be discontinued at some time due to environmental issues.

[AlanBeckett]

I'm not convinced that this Christmas theme is a good idea
Can I have the uual one back please?

Alan

[Joe]

The 'Change Theme' box should still be at the bottom of the screen.

- Joe

[Nick]

Another resurrected thread...

Just used some oxalic acid to clean some rather mucky bits from a DAC90A that's in the shed - in particular, the cord drum from the tuning capacitor... very rusty, it was...

Ad hoc chemistry - about two not-very-heaped teaspoon-fulls of oxalic acid crystals to about a litre of warm water - stir well with something plastic... Wear gloves and do not inhale the fumes - its toxic stuff - keep it away from animals, food, yourself etc.

Came up magic in about an hour - nice & shiny now... I should really start another thread on this as oxalic acid doesn't really clean brass, so much as leach all the zinc out of it leaving it copper-coloured... its really good at attacking oxides, hence it targets the rust and leaves the steel bits untouched...

           

Here's a hint - that tub does NOT contain creamy Greek yoghurt. Do NOT put it on your muesli and adding honey to it is a definite no-no

[Mark R]

No it is ok Nick meandered back.

cheers Mark

[dennishoy]

Nick, Phosphoric acid is used in many proprietry solutions for cleaning rusty ferrous items. The oxide (rust) is converted to a phosphate which also passivates the steeel underneath.

I found this gobbledegook too, if you can make any sense of it:-

"A method is disclosed for coating rusted metallic surfaces which comprises (a) removing loose rust particles by superficial surface treatment, (b) applying a coating containing about 55-95% by weight of an aliphatic(meth)acrylic monomer having at least two sites of polymerizable unsaturation and having a 25.degree. C. vapor pressure of no greater than about 0.5 mmHg and a 25.degree. C. viscosity in the range of about 3 cps to about 100 cps, about 0.5-5.0% by weight of a peroxide curing system and about 5.0-35.0% by weight of a drying oil-based oxygen scavenger system, and © allowing the coating to cure under ambient conditions."

So there you go.... no excuses for a rusty chassis now.