Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

Scratches in paint on aluminum frame. Oxidization?

Notices
Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

Scratches in paint on aluminum frame. Oxidization?

Old 08-16-11, 10:22 AM
  #1  
AlphaDogg
I let the dogs out
Thread Starter
 
AlphaDogg's Avatar
 
Join Date: Apr 2011
Location: Boulder, CO
Posts: 1,934

Bikes: 2011 Fuji Roubaix 1.0, 2003 Ti Merlin Solis, & 1994 Raleigh MT200

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Scratches in paint on aluminum frame. Oxidization?

I have had my bike with aluminum frame since April. Since then, it has seen heavy use. Over 1100mi on it since the date of purchase. Inevitably, when I lean it against something to lock it up, it gets scratched. Some of the scratches are light, some are deep enough to uncover bare aluminum. Is there something I should do to prevent oxidization? Should I be worried about oxidization? It spends 95% of its time in dry conditions, with very limited rain-riding. When I'm not riding it, it stays in the garage.
AlphaDogg is offline  
Old 08-16-11, 10:54 AM
  #2  
fietsbob
Banned
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 43,599

Bikes: 8

Mentioned: 197 Post(s)
Tagged: 0 Thread(s)
Quoted: 7607 Post(s)
Liked 1,309 Times in 822 Posts
If you are prone to worrying, you will ..

Add: clear nail polish will do a metal covering job.

Last edited by fietsbob; 08-19-11 at 10:50 AM.
fietsbob is offline  
Old 08-16-11, 11:06 AM
  #3  
FanaticMN
Senior Member
 
Join Date: Jul 2011
Location: Minneapolis, MN
Posts: 199

Bikes: Trek Allant

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Aluminum oxidation is self-limiting (think about all the bare aluminum screen doors you've seen).
FanaticMN is offline  
Old 08-16-11, 11:06 AM
  #4  
UberGeek
Senior Member
 
Join Date: Aug 2011
Location: Buffalo, NY
Posts: 1,144

Bikes: Schwinn Tourist (2010), Trek 6000 (1999)

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
https://www.historyofaluminum.com/usage.php
UberGeek is offline  
Old 08-16-11, 06:31 PM
  #5  
HillRider
Senior Member
 
Join Date: Aug 2005
Location: Pittsburgh, PA
Posts: 32,729

Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!

Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 1610 Post(s)
Likes: 0
Liked 457 Times in 352 Posts
If you are concerned you can touch up the scratches using Testors model paint or nail polish. The former is available at any hobby shop and the later at any Wal-Mart, both is a bewildering range of colors. One should be close.

Otherwise automobile wax will prevent oxidation but it isn't a serious problem unless the bare aluminum is exposed to a lot of salt.
HillRider is offline  
Old 08-16-11, 06:44 PM
  #6  
AEO
Senior Member
 
AEO's Avatar
 
Join Date: Jun 2007
Location: A Coffin Called Earth. or Toronto, ON
Posts: 12,258

Bikes: Bianchi, Miyata, Dahon, Rossin

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 2 Times in 2 Posts
aluminium is very resistant to corrosion by water(H2O) and salt(NaCl).
it's very weak against ammonia (NH3) and mercury.

It's also does not like being in contact with other metals because of galvanic corrosion.

Bare aluminium is not possible in open air, because the outside layer oxidises upon contact with oxygen.
__________________
Food for thought: if you aren't dead by 2050, you and your entire family will be within a few years from starvation. Now that is a cruel gift to leave for your offspring. ;)
https://sanfrancisco.ibtimes.com/arti...ger-photos.htm
AEO is offline  
Old 08-16-11, 06:47 PM
  #7  
AlphaDogg
I let the dogs out
Thread Starter
 
AlphaDogg's Avatar
 
Join Date: Apr 2011
Location: Boulder, CO
Posts: 1,934

Bikes: 2011 Fuji Roubaix 1.0, 2003 Ti Merlin Solis, & 1994 Raleigh MT200

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Originally Posted by HillRider View Post
If you are concerned you can touch up the scratches using Testors model paint or nail polish. The former is available at any hobby shop and the later at any Wal-Mart, both is a bewildering range of colors. One should be close.

Otherwise automobile wax will prevent oxidation but it isn't a serious problem unless the bare aluminum is exposed to a lot of salt.
I think I will buy some blue, white and black paint or nail polish to try to match my bike's blue color as closely as possible.

That's good to know before I do any winter riding in the snow and ice. I'm not entirely sure that I will be doing winter riding, but it's nice to know before I do it, if I do it.
AlphaDogg is offline  
Old 08-16-11, 06:54 PM
  #8  
AlphaDogg
I let the dogs out
Thread Starter
 
AlphaDogg's Avatar
 
Join Date: Apr 2011
Location: Boulder, CO
Posts: 1,934

Bikes: 2011 Fuji Roubaix 1.0, 2003 Ti Merlin Solis, & 1994 Raleigh MT200

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Aluminum really doesn't like mercury, you're right.

AlphaDogg is offline  
Old 08-19-11, 05:54 AM
  #9  
lewd reed
Junior Member
 
Join Date: Jun 2011
Location: Blue Mountains, Australia
Posts: 23
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by AlphaDogg View Post
Inevitably, when I lean it against something to lock it up, it gets scratched.
If the paint is scratched to the bare metal, the oxidization will indeed start to fester around that area. You might find though, that it's not really noticeable - especially if you touch up the spot before much moisture gets in there.

My Cannondale has a few oxidization cancers - one particularly ugly one on the rear brake stop. I've spoken with a reputable enameler, who informs me that it is not uncommon on aluminum frames where the finish has been breached right through, and that it is simply more noticeable under clear coat on bare metal like mine.

From the sound of things though, you aint too worried about throwing it against the rail to chain it up, so I can't see you being to fussed about a little under-coat blemish.
lewd reed is offline  
Old 08-19-11, 10:55 AM
  #10  
fietsbob
Banned
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 43,599

Bikes: 8

Mentioned: 197 Post(s)
Tagged: 0 Thread(s)
Quoted: 7607 Post(s)
Liked 1,309 Times in 822 Posts
Wrap the frame with tape , old inner-tube opened up makes a decent tape for that.
fietsbob is offline  
Old 08-19-11, 02:11 PM
  #11  
Chombi
Senior Member
 
Chombi's Avatar
 
Join Date: Jul 2009
Posts: 11,138

Bikes: 1986 Alan Record Carbonio, 1985 Vitus Plus Carbone 7, 1984 Peugeot PSV, 1972 Line Seeker, 1986(est.) Medici Aerodynamic (Project), 1985(est.) Peugeot PY10FC

Mentioned: 21 Post(s)
Tagged: 0 Thread(s)
Quoted: 142 Post(s)
Likes: 0
Liked 12 Times in 12 Posts
Originally Posted by FanaticMN View Post
Aluminum oxidation is self-limiting (think about all the bare aluminum screen doors you've seen).
To some point it is, but if the material is continually exposed to corrosives, it can still corrode to the point of perforation. Back in the 80's, I remember seeing a bus in the Milwakee Greyhound station with its rear aluminum body panels "swiss chessed" with what looked to be millions of little jagged holes from being corroded by the winter road salt spray continuously. We always think of aluminum as a corrosive resistant material but seeing that, convinced me that Aluminum can corrode just as bad as steel in some conditions.

Chombi
Chombi is offline  
Old 08-20-11, 09:28 AM
  #12  
MNBikeCommuter
Senior Member
 
MNBikeCommuter's Avatar
 
Join Date: Nov 2010
Location: Minnesota
Posts: 667

Bikes: Cannondale '92 T600 '95 H600 '01 RT1000

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 29 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
My '95 Cannondale hybrid has 17k Minnesota winter miles on it. The salt does cause "bubbly" corrosion on the bare aluminum, which spreads under the surrounding paint. I just scrape it off with a screw driver, sand it lightly, and paint over with a metal primer and matching paint (black). More of an issue is that the rims corrode a bit around the stem hole, making it impossible to remove the tube without ruining it if I get lazy and don't periodically clean out the hole before it gets to that point.
MNBikeCommuter is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
El Gato27
Bicycle Mechanics
18
11-01-18 08:12 AM
Ed Holland
Bicycle Mechanics
36
06-26-18 09:01 AM
lightspree
Framebuilders
4
04-14-16 08:00 PM
thirdgenbird
Framebuilders
21
11-11-15 11:37 AM
Darth Yoda
General Cycling Discussion
2
10-28-13 08:30 PM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.