Aluminium corrosion

[matty]

Hello Everyone,
Picked up a Beirette VSN at the local flea market yesterday, another poor orphan I felt sorry for but I couldn't resist another old communist camera and it was only 50p. (Will try to post some pics in the next day or so.) It looked in pretty poor condition, very dusty and dirty with rust on the metal fittings of the case, the focusing ring was stuck and the shutter was sticking. Anyway got it home and opened it up. It was clean inside so I wiped it down, worked the shutter and popped some oil on the focusing ring and things started to move properly. It doesn't look so bad now so I think it might be usable. The only thing I'm not sure of how to deal with is corrosion on the metal top and bottom, I think its aluminium and there is quite a bit of pitting on it. Does anyone know how to get rid of this? Any suitable chemicals or cleaning agents or do I need to look at using a very fine abrasive?
Thanks
Matty

[Deleted]

I've found that wiping down aluminum surfaces with a microfiber cloth and lighter fluid works well. The lighter fluid seems to get down in the nicks and pits and dissolve the crud and enhances the shine.

[Stephen]

Notes for reference, I worked making aluminium Optical and scientific instruments for many years.

Aluminium is not easy to clean once pit marks are on the surface. Aluminium comes in many forms, along with Dural types, where copper, nickel, etc., is added to give greater strength. Most cameras have pure aluminium, with an anodised surface.

The surfaces of all types protects itself by oxidising, forming a fine layer of aluminium oxide, which is a very hard and tough material, use for abrasives etc.

This oxide is formed very quickly on the raw metal, and in anodised aluminium is forced to form by electrolysis, after cleaning with acid. the oxides dyes and stains easily for colours or is left plain with a satin finish.

The troubles start with damage to the surface exposing raw aluminium and marks appear where it starts, spreading the corrosion marks, and usually making white powder.

Acid from the skin can pit mark cameras etc., as can exposure to salty sea spray.

So once the marks are there and deep, then nothing will improve things much in appearance, but a clean with a weak acid solution, hydrochloric, or sulphuric, then neutralising with soda, then oiling to keep air off it will stop most corrosion.

With cameras, the surface could be bead blasted, or random wire brushed, after cleaning, which will restore a more even finish.

You can use aluminium cleaners designed for car wheels, the best are two part, a prep acidic cleaner, then a waxy polish to neutralise and protect.

If the surface is already beaded satin finish, then you have problems! Only further bead blasting will retain any semblance of the original finish.

If polished aluminium, then used chromium cleaners, metal polishes, and finish off with real car wax.

So, not easy to bring back the old appearance, unless bead blasting is available (note, not grit blasting, but very fine glass bead is used to hammer the surface.

For the Beirette, I would suggest Aluminium wheel cleaners, gently applied in a rotary motion with micro cleaning cloth. Finish with wax, a hard grade car polish, or beeswax furniture polish.

Hope this helps.

Stephen.

[Stephen]

Feb 28, 2013 11:29:40 GMT -5 @wayne said:

I've found that wiping down aluminum surfaces with a microfiber cloth and lighter fluid works well. The lighter fluid seems to get down in the nicks and pits and dissolve the crud and enhances the shine.

Good advice, the reason this cleaning with petrol, or alcohol works, is that the surface of the oxide is porous! This porous nature of the minute layer of oxide is why coloured dye sticks to aluminium so well for multi coloured surfaces.
But is also absorbs dirt and crud, although most anodised surfaces are treated with sealers, but they wear away, and the surface goes dull.
After the cleaning with petrol use a good real hard car wax, Simonize etc, or hard furniture polish, this seals the surface again.
Stephen.

[lloydy]

Would 'Autosol' work ?

autosol.com/

autosol.com/shop/aluminum-polish/

I've used it for many years on aluminium parts, on cars and motorbikes mainly, and it's always worked well on those. It seems just abrasive enough to cut through the oxidised layer the Stephen describes and leave a good finish with a bit of elbow grease.
But as Stephen has already said, deep marks or special finishes are going to be hard to remove and replicate.

[Stephen]

Feb 28, 2013 17:13:28 GMT -5 lloydy said:

Would 'Autosol' work ?

autosol.com/

autosol.com/shop/aluminum-polish/

I've used it for many years on aluminium parts, on cars and motorbikes mainly, and it's always worked well on those. It seems just abrasive enough to cut through the oxidised layer the Stephen describes and leave a good finish with a bit of elbow grease.
But as Stephen has already said, deep marks or special finishes are going to be hard to remove and replicate.

Autosol will work, it is designed to clean steel etc., but is quite OK on aluminium as well. Adding wax afterwards is the key to keeping the finish.
Stephen.

[Stephen]

I did not notice it is the specific aluminium version of Autosol, this should be perfect for the job. I used the Chromium version in the past.

[matty]

Thanks for the advice, once again Camera Collector comes to the rescue, off to score some Autosol now!
Thanks
Matty