Hi All,

I asked here about removing 'corrosion' from an alloy motorcycle wheel
recently and I have now done most of it using a wire brush on an
electric drill and hand wire bush. I just have some light corrosion
left in fifficult to access castings and don't want to paint over it?

It was suggested that ammonia may be good to 'remove' (convert?) this
corrosion (sulphate?) but we don't have any in the cupboard, I'm not
sure where I would go on the high street to get some, what form would
it come in and would it affect (damage / surface hardnen?) the alloy?

All the best ..

T i m

"T i m" wrote in message
...
Hi All,

I asked here about removing 'corrosion' from an alloy motorcycle wheel
recently and I have now done most of it using a wire brush on an
electric drill and hand wire bush. I just have some light corrosion
left in fifficult to access castings and don't want to paint over it?

It was suggested that ammonia may be good to 'remove' (convert?) this
corrosion (sulphate?) but we don't have any in the cupboard, I'm not
sure where I would go on the high street to get some, what form would
it come in and would it affect (damage / surface hardnen?) the alloy?


Aluminium alloy (as I expect you have) must be laquered or otherwise
protected. It will corrode especially on contact with salt, and will look
bad as white aluminium oxide deposits. Laquer as used on alloy car wheels
must be applied to emaculately prepared surface which generally can only be
achieved by mechanical means from a previously oxidised surface.

--
Mike W

"T i m" wrote in message
...
Hi All,

I asked here about removing 'corrosion' from an alloy motorcycle wheel
recently and I have now done most of it using a wire brush on an
electric drill and hand wire bush. I just have some light corrosion
left in fifficult to access castings and don't want to paint over it?

It was suggested that ammonia may be good to 'remove' (convert?) this
corrosion (sulphate?) but we don't have any in the cupboard, I'm not
sure where I would go on the high street to get some, what form would
it come in and would it affect (damage / surface hardnen?) the alloy?

All the best ..

T i m

You won't remove corrosion with etch cleaners or other chemicals which will
leave the surface looking good. Pitting and discolouration are the usual
result. The best manual method is Scotchbrite nylon abrasive pads which you
can get from engineering supply merchants. This leaves a fine burnished
surface without deep scratches. You can wrap small bits round a thin stick
to get into fiddly areas. Another way is vapour blasting which is a sort of
fine bead blasting with beads suspended in a water jet.
--
Dave Baker
www.pumaracing.co.uk

On Sat, 20 May 2006 22:46:02 GMT, "VisionSet"
wrote:


"T i m" wrote in message
.. .
Hi All,

I asked here about removing 'corrosion' from an alloy motorcycle wheel
recently and I have now done most of it using a wire brush on an
electric drill and hand wire bush. I just have some light corrosion
left in fifficult to access castings and don't want to paint over it?

It was suggested that ammonia may be good to 'remove' (convert?) this
corrosion (sulphate?) but we don't have any in the cupboard, I'm not
sure where I would go on the high street to get some, what form would
it come in and would it affect (damage / surface hardnen?) the alloy?


Aluminium alloy (as I expect you have) must be laquered or otherwise
protected. It will corrode especially on contact with salt, and will look
bad as white aluminium oxide deposits.

Understood.

Laquer as used on alloy car wheels
must be applied to emaculately prepared surface which generally can only be
achieved by mechanical means from a previously oxidised surface.

Ok, and that's the bit I was trying to do.

Recap: The front tubeless tyre was leaking at the rim joint so I
removed the tyre and found corrosion had lifted the paint in several
places and hence the leak. I removed all the corrosion / remaining
paint within the rim area and used paint stripper to remove the pain
from the reast of the wheel. In some places the paint looked ok but
there were areas of corrosion underneath. I now just have a few
patches of (white) corrosion left but in the bottom of deep cast holes
around the hub and disk brake mounts.

I felt a chemical solution that would remove or 'kill' these few final
patches might make the job easier pre a final cleaning and acid-etch
priming paint etc?

All the best ..

T i m

p.s. I have 'painted' many alloy parts (mainly motorcycle) over the
years and they are still looking ok .. unless as uou say, the salt
get's under it via a stone chip etc. ;-(

On Sun, 21 May 2006 02:06:57 +0100, "Dave Baker"
wrote:


"T i m" wrote in message
.. .
Hi All,

I asked here about removing 'corrosion' from an alloy motorcycle wheel
recently and I have now done most of it using a wire brush on an
electric drill and hand wire bush. I just have some light corrosion
left in fifficult to access castings and don't want to paint over it?

It was suggested that ammonia may be good to 'remove' (convert?) this
corrosion (sulphate?) but we don't have any in the cupboard, I'm not
sure where I would go on the high street to get some, what form would
it come in and would it affect (damage / surface hardnen?) the alloy?

All the best ..

T i m

You won't remove corrosion with etch cleaners or other chemicals which will
leave the surface looking good.

Sorry I didn't mention what I was going to do next Dave ... acid
etch prime, filler primer, undercoat, top coat and possibly a 'two
pack' laquer.

Pitting and discolouration are the usual
result.

A pain on things that you want to remain 'natural' looking I agree.
This front wheel, although pretty well clean of most of the corrosion
etc is currently a patchwork of colours, brushed bits, paint stripped
bits, hard corroded (black) bits .. ;-(

The best manual method is Scotchbrite nylon abrasive pads which you
can get from engineering supply merchants.

Or from under the sink ;-)

This leaves a fine burnished
surface without deep scratches. You can wrap small bits round a thin stick
to get into fiddly areas.

I used that to remove the little bits that paint stripper didn't quite
get. I'll go over the whole wheel with some fine wet-n-dry (wet) to
remove any burrs etc next.

Another way is vapour blasting which is a sort of
fine bead blasting with beads suspended in a water jet.

Hmm, that sounds easier ;-) I did consider getting the whole wheel
bead blasted but it's the finding the right place that would do it for
a drink, getting it back, finding they'd missed a bit or been a bit
agressive etc etc. Experience has told me d-i-y is the only way I get
what *I* want.

A few years back I bought my daughter a little Yamaha TY-80 (4 speed
trials bike) that was in a pretty scruffy (but functional) state. I
even stripped the spoked wheels down, painted the hubs with an ally
looking paint and rebuilt the wheels with new rims and spokes. When I
was fininshed it looked pretty good (can't say 'like new' because it
was over 15 years old *then*!).

I get great pleasure 'restoring' stuff .. don't think I could do so
for a living though .. ;-(

All the best ..

T i m

T i m wrote:
I did consider getting the whole wheel bead blasted but [...]

Can you get a wheel cheaper than the cost/effort of salvaging
this one, e.g. from ebay?

On 21 May 2006 11:31:07 +0200, Chris Bacon
wrote:

T i m wrote:
I did consider getting the whole wheel bead blasted but [...]

Can you get a wheel cheaper than the cost/effort of salvaging
this one, e.g. from ebay?

I don't think so Chris .. there is basically nothing wrong with
*this* wheel and I would probably do the same thing to anything but an
immaculate / brand new wheel anyway (it's just how I am). ;-(

Whenever I have bought a new (to me) motorcycle I always give it a
'quick once over' but that often ends up with me doing like I'm doing
now .. but I only ever need to do it once and then can ride the things
into the ground knowing those little matters (like an oversize inner
tube for example) aren't going to come back to bite me later on ..?

Also I don't feel a machine is *mine* until I have got to know it's
internals a bit ..(and generally I'm the better for doing so *should*
something happen on the road ..). Also be personalising it a bit (like
these rims were white and I might do them silver / ally) means it's
easier to spot / less easy to dispose of should it get knicked?

All the best ..

T i m

On Sun, 21 May 2006 02:06:57 +0100, "Dave Baker"
wrote:

The best manual method is Scotchbrite nylon abrasive pads which you
can get from engineering supply merchants.

Alumium oxide is hard - go with Garryflex abrasives instead of the
Scotchbrites.

I'm just in from an hour or two in the workshop polishing an old 1940s
suitcase, in what appears to be Birmabright (15% magnesium). I guess
it's demob kit, made from old Lancasters. A filthy job!

As to chemically pickling alumium, then there are plenty of easy recipes
for it. The tricky bit is though that they're much aster on bare alumium
than they are on the oxide - so as soon as you have a pinhole you
rapidly have a big hole in the metal and you still haven't removed the
oxide film. You can use a quick pickle on alumium to clean it
immediately before coating (and I mean immediately!), but it's not an
effective way to remove appreciable grot beforehand - stick with
abrasives.

Some people find www.finishing.com to be useful...

On Mon, 22 May 2006 22:48:44 +0100, Andy Dingley
wrote:

On Sun, 21 May 2006 02:06:57 +0100, "Dave Baker"
wrote:

The best manual method is Scotchbrite nylon abrasive pads which you
can get from engineering supply merchants.

Alumium oxide is hard - go with Garryflex abrasives instead of the
Scotchbrites.

Ok, I'll look our for some.

I'm just in from an hour or two in the workshop polishing an old 1940s
suitcase, in what appears to be Birmabright (15% magnesium). I guess
it's demob kit, made from old Lancasters. A filthy job!

But rewarding? ;-)

As to chemically pickling alumium, then there are plenty of easy recipes
for it. The tricky bit is though that they're much aster on bare alumium
than they are on the oxide - so as soon as you have a pinhole you
rapidly have a big hole in the metal and you still haven't removed the
oxide film.

Ah (and we don't want to do that!) the 'corrosion' I'm talking about
here sits on top of the ally in the form of a white patch that on the
worst bits was quite soft and brushes off reasonably easily (it comes
off in the form of a while powder)l? The darker (black), harder bits
I'm happy to leave as the acid etch primer seems to stick / bond to
that fairly well?

You can use a quick pickle on alumium to clean it
immediately before coating (and I mean immediately!), but it's not an
effective way to remove appreciable grot beforehand - stick with
abrasives.

Hmm, just this is down inside some pretty deep casting / webs (front
bearing hub and disk mount legs) and although I could leave it there
(as it can't be seen once the disk is on) I'd rather not let anything
get a toe-hold under the paint again? I *might* be able to get the
Dremel down there but I couldn't see what I was doing at the same
time. ;-(


Some people find www.finishing.com to be useful...

Bookmarked, thanks Andy. ;-)

All the best ..

T i m