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Old 4th Jan 2012, 5:43 pm   #1
Ian - G4JQT
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Default Cleaning irregularly-shaped parts

How do forum members clean the metallic mechanical bits for a restoration? Particularly irregularly-shaped parts like bulb holders, and various brackets and fixings?

I’ve got a 600ml ultrasonic bath which on the whole gives pretty good results (but perhaps a bit small), using just a strong solution of Flash-type floor cleaner and warm water. (I’ve been meaning to see how effective meths or white spirit is to clean stuff, but that’s better done outdoors I think, and switched off safely at the end of a long mains-extension lead…)

But the bath is not suitable for very small parts as they fall through the basket and rattle in the bottom, which is supposed to be bad for the transducer; neither is the bath much good for removing rust or other types of corrosion.

Aluminium parts come up nicely in a dishwasher or in a solution of caustic soda and I have tried the electrolysis method for steel parts with some success. But I guess I’m after some fluid (acid) I can just chuck stuff in (particularly steel) that is the chemical equivalent of using a wire brush and electric drill!

And what about further corrosion prevention? Without re-plating or painting, is there anything that can be applied? (Just keeping restored items in a dry atmosphere will of course help.)

I’ve looked in the forum archives and Kurust, Jenolte and Finnigans rust beater are mentioned, but it seems they leave behind some primer coating that can be pained. I just want bare metal. Waxoyl was also mentioned. Is this some sort of thin film of oil? Does it protect against corrosion for long?

Thanks and regards,

Ian
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Old 4th Jan 2012, 5:55 pm   #2
MichaelR
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Default Re: Cleaning irregularly-shaped parts

It is not a complete solution for all things but for screws and various small bits and pieces I have found a solution of warm water and lemonjuice to be surprisingly effective.

For rust removal my ideal would be one of these "sandblasting" machines, I would be keen to know if anybody has used them effectively.

Mike
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Old 4th Jan 2012, 6:34 pm   #3
kalee20
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Default Re: Cleaning irregularly-shaped parts

Lemon juice? I use vinegar!

Generally, I'll leave in paraffin or white spirit overnight, and clean with a toothbrush, and sometimes with wire wool if there is surface rust.

Then, a clean with detergent and sometimes a soak for an hour in vinegar, followed by a good rinse, and maybe a sluice off with more white spirit.

An empty squeezy bottle such as what 'Flash' or 'Cif' comes in, is excellent for paraffin and white spirit. But wash out thoroughly and dry first. Then you can spray the stuff exactly where you want it, with a bit of force behind the spray.
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Old 4th Jan 2012, 6:37 pm   #4
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Default Re: Cleaning irregularly-shaped parts

I restore acoustic gramophones, so always have many small screws, clips and other small bits to clean. I use a small Dremel hobby drill, with steel brushes to remove rust, and brass brushes for polishing. Sounds drastic, but it's not powerful enough to remove plating, and if it happens to catch your finger, doesn't do any harm. There are also small felt polishing pads available, to be used with metal polish, but have never needed to use them yet, as the wire brushes leave everything sparkling.

Barry
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Old 4th Jan 2012, 7:24 pm   #5
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Default Re: Cleaning irregularly-shaped parts

A long time in an ultrasonic cleaner does wonders, a long time is hours.
 
Old 4th Jan 2012, 9:12 pm   #6
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Default Re: Cleaning irregularly-shaped parts

I have used ultrasonic baths professionally for decades and would recommend the cleaning agents (and all the tech info supplied) made by the Decon company http://www.decon.co.uk/. Unfortunately, there are number of these for different types of materials and they are are quite expensive, but...they are the dogs' whatsits. For tiny parts, put them in a beaker with enough fluid so that the beaker sits on the cage bottom, but surrounded by water.

Light (i.e. non-dense) solvents like alcohol are not so good in an ultrasonic bath; the dense solvent like Freons and carbon tetrachloride generally did better but are no longer an option. Irrespective of whether you have an ultrasonic bath or not, always do your homework on the chemical compatibility of any cleaning agent on the material. Most of us have got caught out at one time or another and damaged or ruined something

Regarding sandblasting, in recent years there has been a big take up of blasting using baking soda! Not sure about the Uk, but you can buy soda blasting kits in the US cheaply. It is not so aggressive as sand nor does it have health issues. Check out You Tube for videos of people (often with home built kit), doing all kind of wondrous jobs using soda blasting. Seriously impressive cleaning method.

Last edited by Bazz4CQJ; 4th Jan 2012 at 9:17 pm. Reason: comment on blasting
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Old 4th Jan 2012, 9:23 pm   #7
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Default Re: Cleaning irregularly-shaped parts

Quote:
Originally Posted by Ian - G4JQT View Post
I guess I’m after some fluid (acid) I can just chuck stuff in (particularly steel) that is the chemical equivalent of using a wire brush and electric drill!
I have had good results with this stuff http://www.hammerite.co.uk/guide/rust_remover_dip.jsp
It's available from Halfords etc. It dilutes 9:1 and lasts very well.
Leaves bare metal.
Usual disclaimer..no connexion etc just a satisfied user.
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Old 4th Jan 2012, 11:04 pm   #8
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Default Re: Cleaning irregularly-shaped parts

I made a chance discovery a few months ago when I tried to clean the inside on our kettle. We are on a well/spring supply which is high in iron and coates the inside so you can't see where the water level is. I have several times scrubbed it with detergent with limited effect and was experimenting with various cleaners, I squirted a small ammount of dishwasher rinse aid into it intending to boil it up, I forgot about it and when I next looked it was as clear as new. I have just done it again this evening, I squirted a couple of ounces into it then filled it with warm water and in about half an hour it was as clean as a whistle. Dont know how this will work with other things but it sure gets rid of iron stains.

Peter
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Old 5th Jan 2012, 5:07 pm   #9
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Default Re: Cleaning irregularly-shaped parts

Another thing to consider for removing corrosion from metal items is alloy wheel cleaner. The stuff that you apply with a brush is a fairly brutal organic acid, which will happily dissolve pretty much anything non-ferrous. It works a treat on discoloured brass and copper - though it will dissolve those right off if they're just plated onto steel. Just brush it on, agitate it a bit, then rinse it off.

I've put small brass screws that were just lumps of verdigris in a saucer of the cleaner, then taken them out after 30 minutes to leave them sparkling and clean after prodding them with a toothbrush.
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Old 5th Jan 2012, 11:59 pm   #10
Ian - G4JQT
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Default Re: Cleaning irregularly-shaped parts

Thanks for the suggestions everyone. A bigger bath is on the cards and 1.3 litres seems about as big as I'll need if it will fully submerse a normal-sized tuning capacitor.

I'll also certainly investigate the Halford's rust remover suggested by Dave and the alloy wheel cleaner suggested by richrussell, though can you give me more details? I guess there are various types of alloy cleaners out there that work more effectively than others in this application.

Regards,

Ian
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Old 6th Jan 2012, 12:07 pm   #11
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Default Re: Cleaning irregularly-shaped parts

You might have to try different alloy wheel cleaners to find which one works best for the sort of thing you're trying to clean. I found them to be quite variable - but I suppose there's a difference between cleaners designed to be used every week as part of a car washing routine, and ones designed to be used just once to clean up a severely dirty wheel before repainting it.

The stuff I've been using for cleaning up brass light switches is from an alloy wheel repair kit. The kit's in a cardboard box about A5 size, but 2 inches thick. It's got the bottle of cleaner (some sort of organic acid), a brush, a can of silver spray paint, a can of clear lacquer and a sort of shower cap to protect the tyre from being sprayed silver. Obviously you only need the cleaning solution not the rest of the kit!
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Old 6th Jan 2012, 8:12 pm   #12
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Default Re: Cleaning irregularly-shaped parts

There are clearly a multitude of alloy wheel cleaners on the market, but my general experience of them is this;
  1. all of the ones I've checked out have been very strong alkaline solutions, even those described as "acid" (being a chemist, I always have some litmus papers stashed in some corner or other)
  2. generally, I regard them as too aggressive to use on any alloy wheels belonging to me (at least for anything more than 10 seconds), let alone anything more delicate. Show me some wheels with the lacquer peeling off in droves and I'll show you some wheels which have probably been generously doused with alloy wheel cleaner.

But as a last resort, I'd certainly start off using a very dilute solution if I did go down that route.
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Old 6th Jan 2012, 8:33 pm   #13
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Default Re: Cleaning irregularly-shaped parts

Have you tried soaking items in Coca Cola?

Last edited by Mike Phelan; 7th Jan 2012 at 9:50 am. Reason: Added missing "?"
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Old 7th Jan 2012, 9:58 am   #14
Mike Phelan
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Default Re: Cleaning irregularly-shaped parts

Brass items can be cleaned by clock cleaning fluid like Horolene, but don't soak them for too long.
Most are a mixture of detergent, ammonia and oleic acid.

For alloy items like IF cans, dishwasher is favourite. The tablets contain sodium carbonate (washing soda) which partially turns into sodium hydroxide (caustic soda). This etches aluminium.

I use Fertan rust remover for steel; it has tannic acid in it whereas most rust removers (and Coca Cola) use phosphoric acid.

After these cleans I tend to throw all the small items like screws into a jar with cooking oil and white spirit, shake them about for a few days and leave out on a paper towel.
When the spirit has evaporated they are heated on a gas ring to below red heat to harden the film of oil.
If you remember the state of the old "chip pans" you will know what I mean. The process is known as Parkerising.
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Old 7th Jan 2012, 1:53 pm   #15
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Default Re: Cleaning irregularly-shaped parts

Oxalic acid is handy stuff to have around. It comes in a powder form and can be mixed up in large quantities so large parts, like a rusty chassis, can be totally submerged. It's also used as a wood bleach and for removing rust stains from fabrics.

David
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