Go Back  Bike Forums > Bike Forums > Classic & Vintage
Reload this Page >

Seatpost Rehab Thread?

Notices
Classic & Vintage This forum is to discuss the many aspects of classic and vintage bicycles, including musclebikes, lightweights, middleweights, hi-wheelers, bone-shakers, safety bikes and much more.

Seatpost Rehab Thread?

Old 05-24-21, 08:20 PM
  #1  
Roger M 
Senior Member
Thread Starter
 
Roger M's Avatar
 
Join Date: May 2010
Location: Snohomish, WA.
Posts: 2,457
Mentioned: 22 Post(s)
Tagged: 0 Thread(s)
Quoted: 244 Post(s)
Liked 663 Times in 224 Posts
Seatpost Rehab Thread?

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
Roger M is offline  
Old 05-24-21, 08:31 PM
  #2  
SurferRosa
Señor Member
 
SurferRosa's Avatar
 
Join Date: Dec 2018
Location: Pac NW
Posts: 4,642

Bikes: Old school lightweights

Mentioned: 61 Post(s)
Tagged: 0 Thread(s)
Quoted: 1905 Post(s)
Liked 2,148 Times in 1,201 Posts
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.
SurferRosa is offline  
Likes For SurferRosa:
Old 05-24-21, 08:34 PM
  #3  
gaucho777 
Senior Member
 
gaucho777's Avatar
 
Join Date: Aug 2009
Location: Berkeley, CA
Posts: 6,910

Bikes: '72 Cilo Pacer, '72 Gitane Gran Tourisme, '72 Peugeot PX10, '73 Speedwell Ti, '74 Nishiki Competition, '74 Peugeot UE-8, '75 Peugeot PR-10L, '85 De Rosa Pro, '86 Look Equipe 753, '86 Look KG86, '89 Parkpre Team, '90 Parkpre Team MTB, '90 Merlin

Mentioned: 73 Post(s)
Tagged: 0 Thread(s)
Quoted: 626 Post(s)
Liked 659 Times in 242 Posts
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
gaucho777 is offline  
Likes For gaucho777:
Old 05-24-21, 08:35 PM
  #4  
thook
(rhymes with spook)
 
thook's Avatar
 
Join Date: Aug 2009
Location: Winslow, AR
Posts: 2,298

Bikes: '83 univega gran turismo x2, '85 schwinn super le tour,'89 miyata triple cross, '91 GT tequesta, '90 yokota grizzly peak, '94 GT backwoods, '95'ish scott tampico, '98 bonty privateer, '93 mongoose crossway 625, '98 parkpre ariel, 2k'ish giant fcr3

Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
Quoted: 671 Post(s)
Liked 488 Times in 360 Posts
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 is offline  
Likes For thook:
Old 05-24-21, 08:36 PM
  #5  
thook
(rhymes with spook)
 
thook's Avatar
 
Join Date: Aug 2009
Location: Winslow, AR
Posts: 2,298

Bikes: '83 univega gran turismo x2, '85 schwinn super le tour,'89 miyata triple cross, '91 GT tequesta, '90 yokota grizzly peak, '94 GT backwoods, '95'ish scott tampico, '98 bonty privateer, '93 mongoose crossway 625, '98 parkpre ariel, 2k'ish giant fcr3

Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
Quoted: 671 Post(s)
Liked 488 Times in 360 Posts
you guys are fast...lol
thook is offline  
Likes For thook:
Old 05-24-21, 08:44 PM
  #6  
Velikus
Senior Member
 
Join Date: Jan 2021
Location: LA
Posts: 57
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 16 Post(s)
Liked 27 Times in 17 Posts
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.
Velikus is offline  
Likes For Velikus:
Old 05-24-21, 11:29 PM
  #7  
merziac
Senior Member
 
merziac's Avatar
 
Join Date: Oct 2015
Location: PDX
Posts: 8,367

Bikes: Merz x 5 + Specialized Merz Allez x 2, Strawberry/Newlands/DiNucci/Ti x3, Gordon, Fuso/Moulton x2, Bornstein, Paisley,1958-74 Paramounts x3, 3rensho, 74 Moto TC, 73-78 Raleigh Pro's x5, Marinoni x2, 1960 Cinelli SC, 1980 Bianchi SC, PX-10 X 2

Mentioned: 162 Post(s)
Tagged: 0 Thread(s)
Quoted: 2546 Post(s)
Liked 1,819 Times in 1,224 Posts
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.
merziac is offline  
Likes For merziac:
Old 05-25-21, 01:34 AM
  #8  
gaucho777 
Senior Member
 
gaucho777's Avatar
 
Join Date: Aug 2009
Location: Berkeley, CA
Posts: 6,910

Bikes: '72 Cilo Pacer, '72 Gitane Gran Tourisme, '72 Peugeot PX10, '73 Speedwell Ti, '74 Nishiki Competition, '74 Peugeot UE-8, '75 Peugeot PR-10L, '85 De Rosa Pro, '86 Look Equipe 753, '86 Look KG86, '89 Parkpre Team, '90 Parkpre Team MTB, '90 Merlin

Mentioned: 73 Post(s)
Tagged: 0 Thread(s)
Quoted: 626 Post(s)
Liked 659 Times in 242 Posts
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.
gaucho777 is offline  
Likes For gaucho777:
Old 05-25-21, 05:32 AM
  #9  
SJX426 
Senior Member
 
SJX426's Avatar
 
Join Date: May 2008
Location: Fredericksburg, Va
Posts: 8,109

Bikes: '73 Bottecchia Giro d'Italia, '83 Colnago Superissimo, '84 Trek 610, '84 Trek 760, '88 Pinarello Veneto, '88 De Rosa Pro, '89 Pinarello Montello, '94 Burley Duet, 97 Specialized RockHopper, 2010 Langster, Tern Link D8

Mentioned: 58 Post(s)
Tagged: 0 Thread(s)
Quoted: 1096 Post(s)
Liked 802 Times in 494 Posts
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.
__________________
Bikes don't stand alone. They are two tired.
SJX426 is offline  
Likes For SJX426:
Old 05-25-21, 05:44 AM
  #10  
Charles Wahl
Disraeli Gears
 
Charles Wahl's Avatar
 
Join Date: Jul 2007
Location: NYC
Posts: 3,969
Mentioned: 21 Post(s)
Tagged: 0 Thread(s)
Quoted: 390 Post(s)
Liked 202 Times in 129 Posts
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.
Charles Wahl is offline  
Likes For Charles Wahl:
Old 06-07-21, 05:52 PM
  #11  
Roger M 
Senior Member
Thread Starter
 
Roger M's Avatar
 
Join Date: May 2010
Location: Snohomish, WA.
Posts: 2,457
Mentioned: 22 Post(s)
Tagged: 0 Thread(s)
Quoted: 244 Post(s)
Liked 663 Times in 224 Posts

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.



Last edited by Roger M; 06-07-21 at 05:59 PM.
Roger M is offline  
Likes For Roger M:
Old 06-07-21, 06:38 PM
  #12  
jdawginsc 
Edumacator
 
Join Date: Jan 2018
Location: Goose Creek, SC
Posts: 2,363

Bikes: '87 Crestdale, '87 Basso Gap, '92 Rossin Performance EL-OS, Faggin Matrix thingy

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 718 Post(s)
Liked 568 Times in 385 Posts
Umm...that’s a show piece!
__________________
1987 Crest Cannondale, 1987 Basso Gap, 1992 Rossin Performance EL, 1990ish Van Tuyl, 1980s Vanni Losa Cassani thingy, 1988 Faggin Matrix with not Matrix tubes, 1990ish MBK Atlantique, 1982 Rossin Record, 1987 Trek Elance

jdawginsc is online now  
Likes For jdawginsc:
Old 06-07-21, 07:25 PM
  #13  
SurferRosa
Señor Member
 
SurferRosa's Avatar
 
Join Date: Dec 2018
Location: Pac NW
Posts: 4,642

Bikes: Old school lightweights

Mentioned: 61 Post(s)
Tagged: 0 Thread(s)
Quoted: 1905 Post(s)
Liked 2,148 Times in 1,201 Posts
Originally Posted by Charles Wahl View Post
That post looks to be on the border of "don't bother, too far gone"... I don't think it will ever look great.
"Rrrrrnnt."
SurferRosa is offline  
Likes For SurferRosa:
Old 06-07-21, 07:55 PM
  #14  
randyjawa 
Senior Member
 
randyjawa's Avatar
 
Join Date: Apr 2007
Location: Thunder Bay, Ontario, Canada - burrrrr!
Posts: 10,920

Bikes: 1958 Rabeneick 120D, 1968 Legnano Gran Premio, 196? Torpado Professional, 2000 Marinoni Piuma

Mentioned: 187 Post(s)
Tagged: 0 Thread(s)
Quoted: 1131 Post(s)
Likes: 0
Liked 968 Times in 587 Posts
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.
__________________
"98% of the bikes I buy are projects".
randyjawa is offline  
Likes For randyjawa:
Old 06-07-21, 08:38 PM
  #15  
Charles Wahl
Disraeli Gears
 
Charles Wahl's Avatar
 
Join Date: Jul 2007
Location: NYC
Posts: 3,969
Mentioned: 21 Post(s)
Tagged: 0 Thread(s)
Quoted: 390 Post(s)
Liked 202 Times in 129 Posts
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".
Charles Wahl is offline  
Likes For Charles Wahl:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.