Anodising alloy parts
- Thread starter Haakon
- Start date
Nambra
Definitely should have gone to specsavers
Anodising shouldn't peel off, it's a molecularly bonded surface treatment - it should only be susceptible to scratches and might fade over time as well.
It sounds like you have paint or powder coating that is coming off, which should be easy to touch up with a spray enamel. Got any pics?
It sounds like you have paint or powder coating that is coming off, which should be easy to touch up with a spray enamel. Got any pics?
Mrlinderman
Likes Dirt
As above, anodizing will not peel, many companies are now using a technique which gives the look and feel of anodization but is really just a cheap cover up technique, a good example is Sistema water bottles, they look like they are anodized but if you subject them to temperatures over 100deg for extended periods the coating will flake and start to peel off. spray touch up may work if you can match the coating
Rhys_
Likes Bikes and Dirt
Yes, and I'd recommend avoiding it unless you really set on it.
As material is removed during the etch process, bearing bores and the like need to be protected or else you might end up with play. You can use special anodising/powdercoating tape which is meant to withstand both the acidity and temperatures experienced during the process or, even better, your anodiser might have suitable nylon plugs. I went through the process recently and whilst the results were good, it was not cheap and it was a lot of mucking around.
pink poodle
気が狂っている男
The only justification (given the price and risk barriers) for doing this is of you're going purple.
Haakon
has an accommodating arse
They're hubs I bought for a wheel build. Had bought them on the understanding they were in perfect nick, but consistant with my luck of late with machinery the rear hub is not cosmetically perfect. They look like theyve been stored in cold wet conditions for a while.
Just exploring options for reinstating the perfect condition while I have the hub bare....
Mrlinderman
Likes Dirt
Yes you can mate but be aware for every 2/1000" of coating 1/1000" of raw metal is consumed in the bonding process, the strip the previous anodization layer you will loose that metal, so make sure no part of the item is measurement sensitive.
coating can vary from 0.5 to 150 micrometers in thickness, most of the time anodization is done in acid baths so the parts you do not want touched (bushing area or bearing area etc) will need to be sealed so you don't loose any material
Nambra
Definitely should have gone to specsavers
Interesting pics Haakon, clearly cosmetic marks that won't affect performance, but how they got there is a bit of a mystery. As Mrlinderman suggested, it looks to be an anodised look-alike surface finish.
Perhaps there was a quality issue with Giant and the raw aluminium was not properly cleaned before the finishing coat was applied. Or, the previous owner had little regard for looking after his spare hubs and they bounced around in his tool drawer for a bit before you bought them.
If the coating continues to flake off, I'd be thinking it was a manufacturing problem, but as they're second hand you'd have little chance of a warranty claim.
If they were my hubs, I think I'd just go to an auto shop and get one of those stone chip repair paint pens and touch up the marks. You'd need to look hard to see your touch up work and it would probably be fairly resistant to being cleaned post ride.
Perhaps there was a quality issue with Giant and the raw aluminium was not properly cleaned before the finishing coat was applied. Or, the previous owner had little regard for looking after his spare hubs and they bounced around in his tool drawer for a bit before you bought them.
If the coating continues to flake off, I'd be thinking it was a manufacturing problem, but as they're second hand you'd have little chance of a warranty claim.
If they were my hubs, I think I'd just go to an auto shop and get one of those stone chip repair paint pens and touch up the marks. You'd need to look hard to see your touch up work and it would probably be fairly resistant to being cleaned post ride.
Haakon
has an accommodating arse
Me? OCD? Don't know what you're talking about... :eyebrows:
But if I'm going to have them apart anyway and there was an easy solution... Touch up pen looking like best option.
Haakon
has an accommodating arse
No actual impact marks on them, and id expect to see scratches not flaked paint (?). Meh. I'll still use them, at least they're not on the front hub I can see when riding!
SummitFever
Eats Squid
Hubs look painted. If looks are super important, remove the internals and bearings, get the outside sandblasted and give them a coat of paint. Sand blasting will give the parts a finish that paint will stick too like crazy. I've re-done many alu parts with this approach. If good quality paint is used, then they will stay looking good for a long time. It helps if you have your own blasting cabinet, but if you get it done, just tell the guys to not remove any material from the bearing seats / sealing surfaces.
That looks liks a good way to clean cassettes. A buddy picked one up to clean parts from an old engine he is rebuilding, pretty amazing before and after pics on 30 year old parts that were covered in baked on crud.Hubs look painted. If looks are super important, remove the internals and bearings, get the outside sandblasted and give them a coat of paint. Sand blasting will give the parts a finish that paint will stick too like crazy. I've re-done many alu parts with this approach. If good quality paint is used, then they will stay looking good for a long time. It helps if you have your own blasting cabinet, but if you get it done, just tell the guys to not remove any material from the bearing seats / sealing surfaces.