Rust on headtube lug - evaporust?
 

I’ve gotten plenty of rust off of components before but have yet to encounter it on a key structural point of a frame so I thought I’d ask. Doesn’t look bad other than aesthetically. Assuming it’s safe, should it be left as is and have nail polish put over it? Or is it worth putting some evaporust gel on? Steel wool first perhaps?

Rest of the frame is super clean so this is odd. Perhaps water stuck under the cable?


https://cimg9.ibsrv.net/gimg/bikefor...0dba1f599.jpeg

That's nothing.

Put the magic stuff on it and let it work, dab a little rust primer on, cover that with whatever you use to match the rest, ride.

You're probably right about it being water, or more likely sweat, under the cable. I agree that it's very minor and will easy to clean up with Evaporust.

Thanks guys! It being a lug just made me a little nervous as this isn’t my bike and I want the person riding it to be safe.

before applying evaporust, sand down the edges of the rusted area to remove any loose/overhanging paint too. that will help ensure the paint that is left is well adhered to the frame and wont just chip off shortly after you touch up the area.

Evaporust now makes a "gel" for just this sort of "spot treatment" or so I read. But you could make something like a "bandage" of guaze or cotton ball soaked in your choice of rust killer and tape it in place
Oh the OP mentions "gel" I did not read carefully...new product to me and have not tired it yet.

Is that a 80s sub 700 Trek?

Sure is! 1987 520. The paint is insane on these. Really nice bike too. 531 frame, generous clearance, pretty long wheelbase, triple, all the braze ons, cantis. Solid components for the year too.
https://cimg9.ibsrv.net/gimg/bikefor...ca4a42c84.jpeg

Your comments was not made in vain. I also read past the mention of gel by the OP and didn't know they made it in gel now. I've been soaking paper towels in the liquid and wrapping them around things like this with plastic wrap. It doesn't work very well on this sort of spot. I just ordered some of the gel. :thumb:

Andy_K and unworthy1 I recently used the gel for the first time on some hard to reach spots on components that I didn’t want to remove and soak and I’m happy to say it worked as well as the liquid.

I asked about it being a Trek because maybe the "key structural part" is not so key since the head tube and head "lugs" are cast as one piece and then brazed to top and down tubes. The paint on my 85 620 seems to be the thinnest and least protective at the head tube lug.
Touch up for sure.

Wait what? How have I never come across this info?
So the head tube is one piece with the lugs and there is effectively no brazing performed on the head tube? So then the head tube is never really a tube on its own, its just part of an intricate cast? Wow- mindblown. Is the casting process/design why in the pictures here, the lugs kiss where the frame pump peg is, even though the frame size is large enough for them to not kiss?

I leaned of it here Fuji Otaku: The Phoenix Project - The 1985 Trek 620 Alights but I still enjoy riding my 620. It is most noticeable in the windows of the lugs that aren't windows after all.

I use the gel with a small brass brush. Works well.