I hvae built a casting rod for a friend, which is mainly used for Harling (Trollling salmon in river).
When he strips off line, the outside of the first ring makes abrasion in the line..
It seems like there is a small unevenness just where the guide foot joins the ring.
How can this be removed? Should it be sanded or should I add some varnish/epoxy there?

A good recommendation will be appreciated.

- Occasional amateur rod wrapper -

I would double check to make sure the guide's ring is not cracked of chipped. that is the usual culprit in your situation.
May take a magnifying lens to see it

We did perform tests on this. When pulling line with pressure through the ceramic only, the line was not damaged.
The line gets the damage when giving out line by pulling off with hand. It's natural to do so with a line-meter-count. The line then will pass on the outside. The exact problem is idenified. It is in the junction between foot and ring.
For certainty, I could spare one of my wifes stockings, but I don't think that is necessary.

Some would argue that line should only run through the inner ceramics. However, it is natural to strip off line like this. I have built similar rods earlier, where this have not been a problem.

Replace the guide.

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QTips work too. Much cheaper than stockings. Check the whole guide. A lot of ceramic cracks happen where the ring meets the frame. Somethings not right.







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Like Tom said In order to not have some kind of line damage later on Replace it maybe also with a higher framed guide ??

Bill - willierods.com

Replace the guide and move on.


Or, you could use a dermal tool with a polishing pad and abrasive compound to polish the rough spot. But, generally speaking - you would be better off by putting a new guide on the rod.