Can someone explain?
 

Am I going crazy or is this salt coming out of my fork??

https://cimg5.ibsrv.net/gimg/bikefor...54cce0060a.jpg
https://cimg8.ibsrv.net/gimg/bikefor...4b350c57bc.jpg

This is a Columbus Zona frameset made to order by Colossi, shipped direct to the local shop where it was built up. I noticed this stuff leaking out of the vent holes last couple times I washed the bike. I've put around 3000 km on it. Never been ridden anywhere but south Louisiana, where there is no real winter and the roads are never salted.

Flux?

I agree, looks like flux. You might want to get some hot water inside the fork and allow it to soak for an hour or so and then flush it out with more water. Flux is acidic and will eat up the paint.

Almost looks like dried linseed oil.

and if so it was squirted inside to prevent rust and the excess is now draining out. I heard from a builder that used to make frames in a production environment that they had problems with forks breaking from water used to rinse out the inside that eventually created rust but never had a problem with flux left after brazing.

What does excess frame saver look like?

IME this discharge is old flux. I've seen this a number of times on frames that have never seen a Frame Saver red hose. My assumption is that water has seeped into the vent hole and carried out some flux when the water tried to exit. Andy.

one way to tell if it's flux, heat it up and see if it turns to liquid. Not on the fork, of course. It's a bit weird that it's migrating though. And I would think that anything put in there as a frame saver would stay put as well. Flux would migrate if it got wet I suppose, but I'm not sure I see why it would be (essentially) symmetric around the hole.

I don't know how paint reacts to flux, but my experience is that it's okay on steel.

The issue with residual flux, IMO, is that it absorbs moisture out of the air. Just look at a joint that's sat after brazing w/ flux. Over time the flux will change, it softens and changes from the glassy nature it has after brazing.

It's my feeling that residual flux can speed up any rusting that might otherwise happen, so I like to remove it as best possible or seal it in so no additional moisture can reach it. Andy

I've posted this before but it bears repeating...

On one of my early frame builds I cleaned the flux off by mechanical means on the outside and didn't do anything on the inside. Painted it up and rode the heck out of it for a good year or so until noticing corrosion on the bottom bracket around where the seat tube inserted into the shell. Looked closer and found some other corrosion in similar locations on the frame. Concluded that flux was migrating through porosity/pin holes in the brazing filler. Not good. Since then I'm a bit manic about removing flux.

Thanks for the answers and discussion, folks. For a minute there I was perturbed and and entertaining bizarre conspiracy theories. The stuff looks exactly like the salt that collects under a hanging wetsuit!

most fluxes have borax as an ingredient, which is a salt.

My colossi was a nightmare. I have a long laundry list of horrible build issues. After looking around on the forums, I see many statements about the quality and issues. I wish I would have saw these before.

Not like that.. excess frame saver looks brown-ish.. kinda like maple syrup, and its sticky.

This is why many will advise newbies to get instruction from a person and not just the written words. A mentor/teacher can help the beginner to develop good practices before the bad ones take root.

At the various shops I've worked in (and owned at one time) we talk about "book smart" home mechanics. While reading up on how to do this or that is a good starting point it lacks the details and nuances that make the difference between "workable" and "good" results.

I didn't soak out flux from my earlier frames until I learned more. But being young those frames either were crashed/retired or were moved on from so I never saw corrosion caused failures. I have cut open a few of my older frames and found rust/flux in the joints and this drove me to do a better job of cleaning out the interiors before painting. Andy (who now has a few soaking/cleaning out methods).