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Other Vintage Household Electrical or Electromechanical Items For discussions about other vintage (over 25 years old) electrical and electromechanical household items. See the sticky thread for details. |
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27th Jun 2019, 11:56 am | #1 |
Nonode
Join Date: Jun 2004
Location: Norwich, Norfolk, UK.
Posts: 2,543
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Polishing aluminium
Hi,
I'm restoring a vintage desk fan and would appreciate any tips on how to remove the corrosion and polish the aluminum fan blades to a high shine. Regards Davids
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27th Jun 2019, 12:11 pm | #2 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,996
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Re: Polishing aluminium
The spidery "snail tracks" are very difficult to get rid of because the corrosion goes somewhat more than just skin-deep.
I would start by using fine [1200] Wet&Dry paper - wet - and lots of elbow-grease! Then something like Solvol Autosol once you've got back to good metal. |
27th Jun 2019, 1:01 pm | #3 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,864
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Re: Polishing aluminium
That looks like it goes deep and is indicative of poor grade aluminium sheet in the first place. Be careful, the stuff may be seriously lacking strength n the affected areas.
David
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27th Jun 2019, 1:08 pm | #4 |
Octode
Join Date: Jul 2004
Location: Dundee, UK.
Posts: 1,813
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Re: Polishing aluminium
Soap filled steel wool, e.g. Brillo pads, are generally very good for producing a fine finish on aluminium but David's warning is very relevant.
The probelm with fan blades, assuming the material is basically sound is that any serious abrasion may possibly affect the balance. Scotch Brite pads are available in a variety of grades and will not remove as much metal, if any, as emery based abrasives. Again if the material can stand it, gentle bead blasting would be effective and could be followed by the steel wool. PMM |
27th Jun 2019, 1:19 pm | #5 |
Pentode
Join Date: Apr 2011
Location: Westgate On Sea, Kent, UK.
Posts: 246
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Re: Polishing aluminium
Try T Cut, Brasso or even toothpaste and buff accordingly.
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27th Jun 2019, 1:45 pm | #6 |
Nonode
Join Date: May 2004
Location: Halifax, West Yorkshire, UK.
Posts: 2,587
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Re: Polishing aluminium
I'd seriously consider spray painting those - starting with a suitable etch primer. Sacrilege to some but pragmatism occasionally makes sense in my view. Choice of colours and finishes too!
Alan |
27th Jun 2019, 2:34 pm | #7 |
Dekatron
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 4,934
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Re: Polishing aluminium
Some of those marks look like they could be the beginnings of cracking, especially the one on the third rivet up from the centre. If you wet them and work them with abrasive it may encourage them to go that way, and they do look like they will need a good deal of material removing. As suggested, a good paint job may be the lesser evil.
B
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27th Jun 2019, 4:43 pm | #8 |
Dekatron
Join Date: Jan 2012
Location: Brentwood, Essex, UK.
Posts: 5,337
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Re: Polishing aluminium
At Plessey, the workshop used to use a rag mop wheel on a bench grinder for polishing aluminium alloy. I don't know if this involved any cutting fluid or whether the rag itself was sufficient, but it was used to good effect on the die cast aluminium alloy eddystone boxes used extensively in one of our projects. The highly polished finish avoided the need for painting or other surface preparation.
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27th Jun 2019, 5:05 pm | #9 |
Octode
Join Date: Jun 2004
Location: Reading/Fakenham, UK.
Posts: 1,323
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Re: Polishing aluminium
How about dipping in caustic soda solution? Although if wire wool doesn't do the trick, not sure what will.
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27th Jun 2019, 5:10 pm | #10 |
Dekatron
Join Date: Nov 2009
Location: Lincolnshire, UK.
Posts: 5,000
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Re: Polishing aluminium
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27th Jun 2019, 5:18 pm | #11 |
Banned
Join Date: Oct 2015
Location: Cornwall, UK.
Posts: 849
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Re: Polishing aluminium
Progressive grades of wet n dry with a little clean engine oil.
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27th Jun 2019, 5:24 pm | #12 |
Dekatron
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 4,934
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Re: Polishing aluminium
The blades would have been formed by pressing, so you'd have to believe there could be some residual stress in there, and they already show signs of corrosion. So, it's not hard to believe that it wouldn't take much to initiate stress-corrosion cracking.
B
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Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch. |
27th Jun 2019, 8:05 pm | #13 |
Dekatron
Join Date: Aug 2016
Location: Colchester, Essex, UK.
Posts: 4,106
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Re: Polishing aluminium
Linishing wheel (may be too thin for that)
Looking at the spidery patterns makes me think that a clear lacquer may have been applied, then later corrosion started at a defect- and crept laterally. The pitting at the centre of the spider could indeed be quite deep. Dave |
27th Jun 2019, 11:12 pm | #14 |
Nonode
Join Date: Jun 2004
Location: Norwich, Norfolk, UK.
Posts: 2,543
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Re: Polishing aluminium
Thanks for all the replies.
As feared, it doesn't sound like it's going to be easy. I think I'll start with some wet and dry paper and see how deep the corrosion goes. Regards David
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28th Jun 2019, 8:05 am | #15 | |
No Longer a Member
Join Date: Oct 2016
Location: Maroochydore, Queensland, Australia.
Posts: 2,679
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Re: Polishing aluminium
Quote:
If that works out I would go for 3M aluminium Polish: https://www.academy.com/shop/pdp/3m-...rer-and-polish I used it on the aluminium chassis of a Bush TV22, which was quite corroded before I started. I used 1200 & then 2000 grade paper prior to the polish: http://worldphaco.com/uploads/BUSH_TV22.pdf It took some hours. Get ready for black-grey hands, which will wash up with detergent. The thing I like about the polish (despite that it works really well) on the label it says; 3M will not be responsible for any damage caused by the polish regardless of any theory put forward by a Lawyer ! After reading that I was even more devoted. |
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28th Jun 2019, 9:02 am | #16 |
Dekatron
Join Date: Aug 2003
Location: near Reading (and sometimes Torquay)
Posts: 3,094
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Re: Polishing aluminium
The other possibility is that the original surface finush was anodisation. It is hard to tell from photos.
If you start applying abrasives to anodised aluminium then you have a big job as you then have to abrade it all off before you can get a nice finish. |
28th Jun 2019, 9:59 am | #17 |
Octode
Join Date: Jun 2004
Location: Hampton Vale, Peterborough, UK.
Posts: 1,698
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Re: Polishing aluminium
600 grade wet/dry, used with T-Cut. Do NOT use Caustic Soda dip, as already warned, unless you wish a textured dull grey finish (if there's anything left to show a finish). Could cracks be sealed with superglue? Just a thought.
Tony |
28th Jun 2019, 10:34 am | #18 |
Nonode
Join Date: Mar 2010
Location: Dukinfield, Cheshire, UK.
Posts: 2,037
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Re: Polishing aluminium
I like that. Did you know that if you laid all the lawyers end to end, it'd be a jolly good start? I can't remember who said that.
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Andy G1HBE. |
28th Jun 2019, 11:17 am | #19 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,864
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Re: Polishing aluminium
I don't like the thought of pieces of thin aluminium sheet getting thrown at speed from a disintegrating fan.
A kid at school once threw a 7 inch single record at someone (who ducked in time) and the record embedded itself edge on into a plywood blackboard. Close call! decapitated by Mr Tambourine Man.... doesn't bear thinking about. David
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Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done |
28th Jun 2019, 2:29 pm | #20 |
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Join Date: Oct 2016
Location: Maroochydore, Queensland, Australia.
Posts: 2,679
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Re: Polishing aluminium
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