By blackmountaincycles,
Filed under: Uncategorized
Aluminum doesn’t rust. But it can corrode to the point it becomes irreparably damaged. Usually anodizing helps protect aluminum – to some extent. Bare aluminum is most readily corroded. The culprit in aluminum corrosion is usually salt. Salt air if you live near the ocean. Salt from roads that are salted in the winter. Salt from sweat that is secreted out of your body.
What can you do to reduce corrosion and protect your frame and aluminum parts? Number one, clean your bike periodically before corrosion sets in. Number two, clean your bike periodically before corrosion sets in. Once corrosion sets in, more drastic measures are required. Here’s a process recommended by Charlie Cunningham to protect your bare aluminum frame.
It’s much easier to work on a frame once all the parts have been stripped off it. Trying to work around parts takes longer and in the case of leaving your crank installed, you are guaranteed to get cut by a chainring at least once. With the frame stripped down, wipe off any excess dirt or grime before starting. Then with a 3M #7447 Scotch-Brite™ pad apply Fluid Film. I use the brush can because it doesn’t take a lot and the brush top makes it easy to apply a bit to the pad. I also use nitrile work gloves, because your hands will get black from working with aluminum and even through the info on it says it’s non-toxic, it’s probably wise. There are also several other applications for a bicycle, but I’m not sure I’d use it for headsets. Could be a good option for seat posts if yours tend to become frozen.
I cleaned up three Cunningham frames recently. One frame took only one application of Fluid Film to clean it up. The other two took two and three applications respectively. I’ve also used it on hub shells that got a new wheel build. Sometimes corrosion builds up under the spoke elbow as it passes over the flange. A little Fluid Film and it will resist further corrosion.
Once the frame is cleaned up, the fluid film leaves behind a treatment that will help prevent further corrosion and with the #7447 Scotch-Brite™ pad, leaves the bare aluminum an nice buffed out appearance – not too polished looking. The next step is an application of Nu-Finish car polish (liquid in this case). This is applied with a finer Scotch-Brite™#7445 pad. This seals and gives a great bare aluminum look. This finish will last longer than if it’s been polished to a mirror finish.
Here’s some before and after shots of the worst of the three Cunninghams.
It will get new decals
There’s still some deep damage, but the Fluid Film and polish are protecting the surface from further damage.
Some riders sweat profusely and some of them have what I call caustic sweat. It’s just gnarly, damaging sweat. I’ve seen carbon headset spacers fused to steerer tubes. Top tubes on steel bikes that get eaten up resulting in rusted out cable stops. And in this case, aluminum handlebars with tiny holes that are eaten away by sweat. In this case, it’s time for a new bar and instructions to remove bar tape, clean, and retape every 6 months or so. Easy to picture the end of a bar folding over because your sweat ate away at the bar.
(What’s playing: Bob Dylan Freight Train Blues)
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10 responses to “Care for your bare aluminum frame…”
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I will stand as witness to the caustic sweat. About every 18 months I need to replace helmets and backpacks. The worst is my big bucks prescription sunglasses. I've learned that anti-refective backside lens coatings are not worth my investment as my sweat melts them right off.
This is a helpful post. Thank you, fellas.
Caustic sweat is blowing my mind. Is there a chance trainer time kills top tubes? I just think of those stationary bikes at the gym, do they have data on caustic sweat?
Also, Mags Oi, I know bug spray with DEET will sure do a number on plastic stuff, is there chance it might be chemical and not you? Some kind of sunscreen or moisturizer perhaps?
If anybody 6'3" ish out there has some nasty old oxidized Cunningham frame, give me a shout!
Thank you so much for this article.
Six years after you wrote this up, here I am done with the process. I have a couple questions if you are still looking at this, after the liquid film step are you just wiping it all off and then going straight to the nufinish or do you need to let the frame sit for a day or something? How long do you let the nufinish sit before wiping it back off? After following the directions on the bottle, letting the polish dry to a haze and wipe it back off, now my fingerprints are really hard to get back out so I feel like I’m doing something wrong.
The whole process is simple. Don’t overthink. Wipe the fluid film off completely with a clean, soft rag right after you apply it. Let the wax dry for 5 or 10 minutes and then wipe off with another clean, soft rag. Finger prints will show if you handle the frame right away because of ever-present oils in your skin. Use cloth gloves if you don’t want finger prints. The finger prints won’t show up once you ride the bike and get it dirty, though.
Ok, that’s the process I followed…just like you described. The problem I’m having now is putting new decals on the bike. I wiped down the area real well with alcohol but the decal won’t stick. When I pull it back off it is covered in a dark metallic film on the backside of the decal and its now unusable. Would that be the liquid film? What do you do to prep for installing new decals?
Not sure I can help you out there. The only thing different I do is clean the area with acetone, not alcohol. That works perfect for me to apply decals.
Hi- about to do this on an 80s Cannondale, and just want to make sure I’m clear on it: scrubbing with the first Scotchbrite of and Fluid Film will not only remove the corrosion but also help prevent future corrosion of the Al ?
Key phrase “help prevent future corrosion…” Yes, that’s the idea.