Any tips for removing corrosion from cast aluminium?

[tekno.mage]

I've found a small Burgess three-wheel bandsaw lurking in the back of the barn. It was in a bit of a state, but the motor works and there are a number of fences, jigs and fittings for it and a new blade. I'm planning on setting it up with a fine-ish narrow blade and using it for small work, to save swapping blades over all the time on the larger Kity bandsaw which we normally use for ripping logs.

Trouble is, the table and fences are cast aluminium and have suffered from that horrible corrosion that affects old aluminium so consequently nothing moves freely.

Anyone know of a quicker (ie chemical) way than mechanical scrubbing or abrading to remove this? I've tried various kitchen/bathroom type cleaners and vinegar, but rubbing with a copper pan scourer had more effect than any of them!! Unfortunately the top of the table is of a ridged design, so cleaning it all up will take an awful lot of rubbing with the scourer :-( I'm also concerned about scratching it up too much, I'd like it to end up nice and smooth and polished so the wood slides over it easily.

tekno.mage

 

[TEO]

This stuff is brilliant, sorted out loads of corroded ali on an old motorcycle I used to have, don't see why it shouldn't work on your saw.

http://www.mothers.com/02_products/05100-05101.html

sorry, don't know how to insert the link properly,
HTH,
T

 

[bugbear]

Trouble is, the table and fences are cast aluminium and have suffered from that horrible corrosion that affects old aluminium so consequently nothing moves freely.

Anyone know of a quicker (ie chemical) way than mechanical scrubbing or abrading to remove this? I've tried various kitchen/bathroom type cleaners and vinegar, but rubbing with a copper pan scourer had more effect than any of them!! Unfortunately the top of the table is of a ridged design, so cleaning it all up will take an awful lot of rubbing with the scourer :-( I'm also concerned about scratching it up too much, I'd like it to end up nice and smooth and polished so the wood slides over it easily.

tekno.mage

When cleaning small tools made from Aluminium (pad saw handles, hacksaw handles), I've had success using the small brass brushes sold for suede shoes.

Presumably a large brass wire brush (not cheap) should work in the same way.

Certainly a steel wire brush is out - it would make terrible scratches.

BugBear

 

[shipbadger]

Can I suggest a fibreglass scratch brush, not the smaller propelling type but the sort with string or cloth bound round the outside. Suppliers include Shesto, Expo or Squires or your local model shop. You should also be able to obtain brass wire scratch brushes from the same source. Don't use acid based cleaners, think about what happens if you leave rhubarb in an aluminium saucepan. The fibreglass brush will also come in handing for removing light rust from other steel tools, they get into nooks and crannies better than wet and dry paper. Your Burgess saw is obviously a later one than mine if it has grooves on the table, mines flat. If it had been flat I'd have suggested a Garryflex block, same suppliers as above.

I have a 32 tpi blade for my saw and it's amazing how thinly you can cut with it installed.

Tony Comber

 

[Digit]

Vinegar!

Roy.

 

[Benchwayze]

Vinegar!

Roy.

Roy,

Is that ordinary Tesco Malt pse?

Cheers
John :wink:

 

[Digit]

It is indeed, Vinegar is Acetic acid and removes corrosion on alli and leaves a dull finish.
But avoid what is listed as NDC, non distilled condiment, it's not true Vinegar.

Roy.

 

[tekno.mage]

After messing about with a variety of different cleaning and kitchen chemicals, I think I've finally cracked it...

First I tried vinegar (plain clear strong vinegar, not any of the nice ones like cider or balsamic!) - and it sat there, looking at me and stinking out the kitchen and the rest of the house but had little or no effect on the bandsaw table even after an hour of one corner being dipped in it. Maybe it would work if I'd used very hot vinegar - but I don't have a large enough container and I don't want the house to smell like a pickled onion factory!

Next, rubbing it with vinegar and salt (? - it was in an old book). It doesn't work.

The fibreglass scratch brush is a good idea - I have a tiny little one and must get a larger one for future projects. The tiny one worked well when I tested it in one of the grooves.

I also tried real brass brushes but the copper pan scourer actually worked better (and far cheaper than brass brushes!) I even wondered about using my new bronze gun brush, (bought last week for cleaning inside morse tapers - a 12 bore gun brush fits up an MT2 taper perfectly) but decided against it.

Next I pull out every cleaning product I have - check each to see what's in them, then end up having a go with most.

I still haven't tried the "alloy wheel cleaning kit" my partner offered me which seems basically to be phosphoric acid and wanrs only to use on alloy wheels and not other aluminium.

The following products don't work...

Bathroom cleaner (the basic stuff, not limescale remover)
Orange spray degreaser (great for degreasing old tools etc before de-rusting them though!)
Barbeque cleaner (probably won;t clean the BBQ either in that case!)
Graffitti remover (don't know where I got that)
Eco-friendly toilet cleaner.

So, left with only the copper pan scourer and elbow grease, I wondered about getting out the old wet'n'dry, until I found a tin of brasso-like metal polish at the back of a cupboard!

It's great - pour some on dry corroded aluminium rubbing in into all the crevices well with a toothbrush, leave for a few minutes, then rub gently over with a non-stick plastic scourer (which goes all black), and finally wash off black mess with washing up liquid to reveal lovely shiney aluminium with the original machining marks still visible and no nasty scratches!

Wish I'd found the metal polish first - would have saved a lot of rubbing and two worn out copper pan scourers!

I think I'll protect the table from future corrosion with frequent applications of Renaissance wax. Now all I have to do is clean up the rest of the parts and re-assemble the saw...

tekno.mage

 

[ondablade]

Hi guys. My take on this sort of stuff is that unless the parts are very small, that even a moderate cost is a very big issue or that getting a decent and regular surface finish is not so important it's generally a good move to take the parts to one of the many places specialising in alloy vapour, bead, grit, water blast and ultrasonic cleaning used by e.g. motorcycle and car restorers.

There's a whole range of processes available that start so fine and so gentle that even highly finished die castings come up looking like new - but progress to options that will shift metal off the surface.

Here's a few blast media options showing one range of options (there's more): http://www.guyson.co.uk/consumables/media.html Glass beads are commonly used on casting to bring them up clean and new looking, but without removing metal.

Apart from Guyson there's lots more, here's a few more from a bike mag (clasic bike and car mag ads are a good source for this sort of stuff):

Eltec near Heathrow - 0845-8721825

Cleenz Macheenz in SE London - www.icmhome.org.uk 020-8766-7164

Rob Binstead Ltd. in Swindon - www.aqua-blasting.co.uk 01793-534300

Check them out before you commit. A quick Google should bring up lots more.

 

[Digit]

I forgot to mention the smell!

Roy.

 

[RussianRouter]

until I found a tin of brasso-like metal polish at the back of a cupboard!

Heavens if I had come acros this post earleir I would have told you that.

There's a better one on the market from Motor factors for Ally and fo the life of me can't remember its name?

Comes in a tube as paste.

 

[RussianRouter]

Remembered...its AutoSol