Roger M

What's everyones preference for getting rid of the zigzag? Is there a dedicated thread for this that I'm not finding?

I have a Super Record seatpost that is marked up, but nothing too deep. I haven't tried to polish it yet, but I'd guess that some Mothers will remove part of the damage.

Thanks in advance for any help on this.

Picture for attention

SurferRosa

Probably lots of aluminum polishing threads...

Mark/tape where it normally sits in the frame and polish everything above that. Use files for the deep stuff. A rounded one helps here. Use good/wet sandpaper (600 grit) for the rest. Finish with a liquid polish like Mother's. Paint the flutes if you wish.

gaucho777 

The usual wet sanding with sandpaper of various grits to get rid of the zig-zags. Seat posts are generally fairly easy to polish. I don't go too crazy below where I know it will be inserted. Different people have their own progression, but I usually start around 400-600, depending on the depth of the scratches, and then progress toward 2000 grit. In this case, I might wrap the sandpaper around a straight edge of some kind and avoid going across the flutes to keep those edges as sharp as possible. Then finish with Mothers or some other polishing compound.

For further reading: https://www.bikeforums.net/classic-v...ng-thread.html

thook

there are certainly threads on the matter. i started a short thread a little while back.....

https://www.bikeforums.net/classic-v...seat-post.html

thook

you guys are fast...lol

Velikus

I've been polishing a lot of bike components lately...for this I'd start with 400 grit to get out the deep scratches, then to 800, then 1000, then 1500, then 2000 and finish with Mothers, which is supposedly 3000-4000 grit level.

merziac

And keep in mind that the more carried away you get the more likely you are to diminish the size, especially with deep scratches.

This can go for stems too.

I kind of like to start out with scotchbrite and some heavy polish, it will clean and scrub off the superficial stuff so you can access the worse and problem defects to decide how far you want to go.

Leaving the bottom alone is a good idea but you may still want to clean it up a bit so it doesn't stick on the deep scratches.

gaucho777 

Also, if this post came from a frame in your possession, don’t forget to clean up the seat tube and any rough edges before putting the zigzags back.

SJX426 

When a gouge is created, material is often removed and some of it is displaced above the original surface. For the section that will be in the seat tube/lug, I would only get rid of the raised portion to avoid diminishing the diameter of the post. Removal of the raised portions above that area would be removed also. Then I would determine how far I would need to go to get reduce the number of gouges. There are some near the top that look deep, causing some concern.

Doing something about it is better than leaving as is.

Charles Wahl

The Super Record post is anodized, and it may help to remove the anodizing with oven cleaner or some other caustic before polishing. That's what I've done on such parts that I wanted to "restore". The anodized layer is harder than base metal, so if your "polishing" reaches the boundary between anodizing and base, the results can look splotchy. I'm not going to get into what caustic to use, or how long to use it; you can look that up online.

By the way, that post looks to me to be on the border of "don't bother, too far gone". You may end up with a decent-looking post, but I don't think it will ever look great.

Roger M

The "before" shot
Update:

I was going to pitch it, after Charles said it was too far gone...

However, I took the advice from some of you here and set about trying to save it. I used materials that I have(meaning: too lazy to go to the hardware store).

Sandpaper: 500/1000/1200
Mothers mag/aluminum polish

I wet sanded the **** out of the backside of the post with 500. I didn't take all of the marks out because they were deep(didn't want to remove too much material).Then I hit everything above the min. line with 1000 and then 1200.

A soft towel and Mothers finished it off. It is no show piece, but will make a nice rider for my blue bike.

Thanks again for the help.

jdawginsc 

Umm...that’s a show piece!

SurferRosa

"Rrrrrnnt."

randyjawa 

When cleaning up a zig zaged seat post, it is important maintain round. Put another way, as you file, sand and polish the post, take the time, using a set of Vernier calipers to ensure that the post is still round and the same diameter, top to bottom. If, however, you file, sand and polish only the section that remains visible, round is no longer as important.

In truth, when I cannot find just the right sized post, I am not above removing a bit of a millimeter so that the post will fit into a smaller seat tube lug. I also make sure to remark the new size so as not to fool the next person who gets the seat post.

This whole procedure is not all that hard to do.

Charles Wahl

Well, I have to eat crow, and admit that turned out a lot better than I thought it would. A bit more shine than a NOS anodized Campy post, maybe I would have stopped at 800 or so, and just polished a bit; but the amount of bling is strictly personal. A higher finish is indeed more corrosion-resistant, and in some respects, easier to clean up again. What @randyjawa says about maintaining round is something I aim at, but it's just a feel thing mostly. Of course the caliper helps, and I've learned the hard way that you need to keep checking, because it's easy to overshoot if you're "just going to take this down to 27.0".