Corrosion on fork dropouts?
 

HI, I recently bought a used bike and have been cleaning it up. I noticed some corrosion or something on the fork tips, after removing the front wheel. The qiuck release on the wheel was fairly rusty, these fork ends look like aluminium though. It looks like a bit of corrosion under clear coat, does that seem right? It reminds me of what happens to the old Shimano Sti levers after a while. Anyway it scrapes off with a fingernail and is hard underneath, and doesn't look like it goes up into the carbon fibre much if at all, would this be ok to ride? I normally just have steel bikes so it's a bit different with those.
https://i.imgur.com/1U2wRYGh.jpeg
https://i.imgur.com/hMpzIYHh.jpeg

Yup. Aluminum corrosion. The key questions is whether the corrosion has proceeded up the fork tip and into the fork tube. Hard to tell from the photo, but if there is an issue, that would be it. Not sure how to diagnose.

elbow grease and time, or you can easily make a scrubber, then hand finish with #0000 steel wool (found at any hardware store), then clear coat it.

tape off the painted part of the fork to protect it before beginning....

here's a vid... there are many, many more.

Thankfully the likely failure more will be the dropout plug coming loose of the blade, and with the other dropout still intact not what i might call a start walking situation. With frequent checking I would consider continuing to ride the fork while also looking for a replacement (good luck on that one). I do think the hand writing is on the wall and it's a matter of time and your being willing to do the diligence until a replacement is found. Andy

Thanks for the replies. I cleaned them up and they look ok but now I am worried about it having gotten up into the fork and possibly loosening them. I'll take it into the bike shop next time I go to town, and I might have another fork that will fit from a bike I bought for parts a few years ago if I need to swap.

You might consider trying a bit of destructive testing. Put a wrench on the dropout and give it a mild twist. If the corrosion has eaten its way up the fork, the fork tip will break loose and twist (don't ask me how I know). If it is solid, then you are good to go per Andy's comment. Check it yearly from now on.

Having suffered from two fork breakages, in my past, during riding I suggest checking this fork far more frequently than once a year. As I mentioned I would consider continuing to ride this fork but would want to monitor the dropout/blade connection quite frequently, and in the meantime be searching for a replacement. If the rider can't or doesn't do this should not ride the fork any longer. Safety is about controlling situations and knowing limits and these take active participation by a user, something we as a society seem to be moving away from, sadly. Andy.

The corrosion on the levers would just be surface corrosion after the clear coat wore off.
Corrosion happening at the junctions of aluminum and carbon, on the other hand, is galvanic corrosion, and is bad news for the joint integrity.

This. It's what you can't see that is the concern. Andy.

Thanks again for all the replies, I'll try the 'destructive' test!