Takingabreak
Dave Yates Fan
- Feedback
- View
How to clean an oxidised front mech
- Thread starter Takingabreak
- Start date
Its lacquer worms.....it needs stripping off then a polish. Its a problem with the latter shimano stuff, the lacquer is thicker, but not so well applied to the alluminium. As soon as you get any uv / physical damage to the lacquer the alluminium starts to corroded under it and the cycle gets worse as the corrosion splits the lacquer.....on an on and on....round and round....
Acf50 is a retardant for corrosion, forming a barrier over the base....but it won't reverse it.
If you have the time on your hands, completly agree with @d8mok wet and dry and polish.....but it is quite a task....as they are fiddly.
Acf50 is a retardant for corrosion, forming a barrier over the base....but it won't reverse it.
If you have the time on your hands, completly agree with @d8mok wet and dry and polish.....but it is quite a task....as they are fiddly.
Takingabreak
Dave Yates Fan
- Feedback
- View
Thanks, I'll see how I get on and then put out a wanted ad 
It's a 28.6 bottom pull mech, I've not spotted anything minty on ebay yet. Of course I do have two minty 31.8 top pulls in my stash - which are of no use to me whatever on this build. I also have a very good condition M563 one but I'm trying to keep it all XT.
It's a 28.6 bottom pull mech, I've not spotted anything minty on ebay yet. Of course I do have two minty 31.8 top pulls in my stash - which are of no use to me whatever on this build. I also have a very good condition M563 one but I'm trying to keep it all XT.
fguki
Senior Retro Guru
Laquer? ... rofl. These parts arent event laquered. Its the very top Aluminium oxyde layer that got "damages" over time by salt (and dirt) for example. Only way is polishing, re-anodizing etc.. Say goodbye to the Shimano logos already. Just clean it, give it surface protection and leave it like it is. Without further and drastical measures like full polishes or paint or re-anodizing the part will never be very much prettier again.
There are loads of Shimano road STIs with this problem. I always thought it may have been due to salts though; there's definitely an affect it just seems to get worse and spread.
novocaine
Old School Grand Master
that's fucked. chuck it in the bin.
what fluffy cock said, strip off the oxide layer, polish it. if you want to keep the graphics you'll need to reapply them, they are water transfer but you'll need to find or draw them and print them.
caustic soda (hydogen peroxide) will strip it, a week solution is best.
wire wool will remove it, as with everything, start with the least damaging and work you way up.
what fluffy cock said, strip off the oxide layer, polish it. if you want to keep the graphics you'll need to reapply them, they are water transfer but you'll need to find or draw them and print them.
caustic soda (hydogen peroxide) will strip it, a week solution is best.
wire wool will remove it, as with everything, start with the least damaging and work you way up.
Takingabreak
Dave Yates Fan
- Feedback
- View
I believe they are actually anodised without a colourant, what you need to get through is the layer that has chemically changed on the alluminium surface. This is normally see as a slightly different colour due to the absorption of the donor in the electrolyte.
Problem is anodising is not infallible...its harder, but more brittle than the underlying metal surface, once damage happens....and once water get involved the corrosion spreads between the differing structures, the expanding under alluminium forcing off the top layer.
The top layer can get so bad ive seen it peel off! It comes of like a sheet. I use the term "lacquer" as a catch all phrase for anything thats covering the surface....
I love the idea of raw aluminium parts though! God that would save ages in either the sheep dip tank (soda will stip anodizing.....but also eat parts to nothing) or sanding! But finish longevity would be measured in days or seconds on a winters day!
Strangely older shimano stuff has much thinner anodising, which got gradually thicker. M700 has hardly any, but stx its quite solid. Oddly, the additional thickness, whilst protecting the finish in one way, seems the enrage the rust worms even more....possibly as the surface is more brittle....im not sure there....
Most painted alluminium is anodized first, as it provides a much better paint key....needed due to the flash corrosion issues of alluminium....as anybody who has tried to weld it will tell you!
Problem is anodising is not infallible...its harder, but more brittle than the underlying metal surface, once damage happens....and once water get involved the corrosion spreads between the differing structures, the expanding under alluminium forcing off the top layer.
The top layer can get so bad ive seen it peel off! It comes of like a sheet. I use the term "lacquer" as a catch all phrase for anything thats covering the surface....
I love the idea of raw aluminium parts though! God that would save ages in either the sheep dip tank (soda will stip anodizing.....but also eat parts to nothing) or sanding! But finish longevity would be measured in days or seconds on a winters day!
Strangely older shimano stuff has much thinner anodising, which got gradually thicker. M700 has hardly any, but stx its quite solid. Oddly, the additional thickness, whilst protecting the finish in one way, seems the enrage the rust worms even more....possibly as the surface is more brittle....im not sure there....
Most painted alluminium is anodized first, as it provides a much better paint key....needed due to the flash corrosion issues of alluminium....as anybody who has tried to weld it will tell you!
Once polished, i use a rag soaked in acf50 to coat the parts.....just wipe them over when you wash the bike. Untouched acf50 claims a 2 year protection cycle.....i would say this is accurate, as we covered unused and stored parts in it ( instead of the age old greased engineers brown paper of old)....
Yes, its a bit more care and attention, but what's the other option? Fill more landfill with perfectly good xt chainsets, that are just cosmetically challenged!
Yes, its a bit more care and attention, but what's the other option? Fill more landfill with perfectly good xt chainsets, that are just cosmetically challenged!
