Removing powder coat from canti brake studs

[Tim Gavin]

I recently had the frame and fork of my '88 Schwinn KOM blasted and powder coated.  I went with a clear powder with a little sparkle in it, and it looks fantastic.  I'll post pictures once I take some.

The blast and powder was less than $150 total (hooray!) but the shop didn't mask the brake posts on the fork or frame (boo!).  The cantilever (and U-brake) calipers don't fit over the now-thicker posts.  This shop is regarded well for bicycle jobs, so perhaps they assigned it to a new guy that day.

What's the best method to remove the powder coat from these spots?

• Sandpaper?  Start with very coarse grit and work finer?
• Wire brush?  I think I have one for my Dremel tool
• Chem stripper?  I could brush it on precisely with a paintbrush
• Razor blade?  (whittling method) May be the easiest way to start 

Regardless of the method, I'll fit a washer around the base of the post to protect the rest of the frame from my efforts.

Thanks,

Tim Gavin

Cedar Rapids, IA

[Bill Lindsay]

I recommend the cloth backed sandpaper.  You rip a 1" wide strip and go back and forth like shoe shine.  

Bill Lindsay

El Cerrito, CA

[WETH]

Tim,

This happened on a a bike I had powder coated.  Sandpaper worked fine.  And all was covered when the brakes were installed on the posts.  I had to do the same thing to the downtube shifter bosses.

All the best,

Erl

[Eric Norris]

I would wipe a little grease or heavy oil on the posts before you install the brakes, so that rust doesn't take hold there. 

–Eric N

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[Chris Chen]

It may also be nice to wear some breathing protection, or sand wet!

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[Tim Gavin]

Thanks, Bill. 

I did exactly that with 50 grit emery cloth, and then followed it up with 150 grit. 

Tool cost: $3.83, and I still have 10 inches of each sheet. The emery cloth is MUSA, and I bought it from a family-owned hardware store.

It took about 10 minutes per post, and the dust was minimal.

I will definitely grease the posts before installing the brakes.

Thanks for the advice, everyone!

I'll take pictures next time I'm home during the daylight.

Tim

Sent from my iPhone

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[Scott Henry]

If it turned out looking that good, and at $150.00.....

Whats the shop info?  Its always good to have options for the future.

Scott

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[Tim Gavin]

On Fri, Jan 15, 2016 at 7:36 AM, Scott Henry <ske...@gmail.com> wrote:

If it turned out looking that good, and at $150.00.....

Whats the shop info?  Its always good to have options for the future.

Scott

Scott-

The shop is Rainbow Paint and Blasting in Cedar Rapids, IA.  http://rainbowrpb.com/

The bike shop I work part-time for (Northtowne Bikes in Cedar Rapids) recommends them for all customer powder requests.  Some folks will order a Surly and have it powder-coated a custom color before assembly.

[Lungimsam]

pics!pics! 

[Tim Gavin]

I added a bunch of pics to my gallery on my '88 Schwinn KOM Project-10:  https://plus.google.com/photos/109817667934112590257/albums/5930329788956113873

The gallery starts at my acquisition of this bike 2.5 years ago (for $75, score!), and progresses from there.  Most recent pics are at the bottom.  Sorry for the lousy quality of the recent pics; the weather is bitterly cold and I'm not often home during good daylight.

Quick history: the '88 KOM was actually the '86-87 Paramountain frame, but they changed it to a Schwinn (without Ned Overend's name on it) after Ned left for Specialized.  

It's full Tange Prestige tubing, with investment cast lugs, made in Greenville, MS (presumably, in whatever Richard Schwinn set up as a southern approximation of "the cage" from the Chicago plant).  It had a great red/white/blue "Captain America" paint job, which Paramount brought back for the '91 PDG Series 90.

It has NORBA race geometry: 71 head angle, 74 seat angle, high BB, short chain stays, long top tube.  It has U-brakes on the chainstays; they aren't terrible with Kool-stop pads, but aren't great either and they constrain the tire to 2.1". 

New pics:

The pics uploaded today showing the bare frame on the nice wood table were taken at my friends' new bike shop, Goldfinch Cyclery.  They show the new powdercoat (clear, with a little sparkle).  You can see the brazing work pretty clearly under the clear coat.  

The pics previous to these show the frame completely bare after blasting (taken in the back shop at the LBS I work for).  I had the original paint blasted off last year because it had some deep scratches and was developing some new rust spots.  My friend, Andy, brazed on some rack and fender eyelets and then I had the blaster clean up after his work.  Another friend shot it with a couple light coats of clear auto paint; this coat looked invisible but consequently proved mostly invisible to rust.  Ergo, I had the frame blasted and powder coated last month.

The following pics (bad sun angle on ugly yellow siding) show it rebuilt.  The bike weighed only 27 pounds in that basic configuration!

Last night, I finished the build by adding fenders, dynamo lights, rear rack, front bag (with basic tool/flat kit), reflectors, computer, and kickstand.  Now, it weighs 34 pounds (shown in the most recent pics, with low lighting in front of some dreary snow).

Build:

The fenders are P65 Longboards.  I think the Longboard P65s are only slightly longer than the non-Longboard version of the same fenders (maybe a little longer in front of the fork), but they do include nice ducktail mud flaps.  

The tires are 26 x 2.1" /559-54 Thunder Burt Liteskins (395 g), with tubes.

The wheels are a set I bought from a German e-tailer.  They're Mavic 317 32h rims laced to an XT T780 hub in the rear and T780 dynamo hub in front.  This wheelset was machine-built, I'm sure, but didn't need much tensioning or truing.  I'm using a 9-speed 11-34 cassette.

The dynamo light is a B&M IQ Cyo Premium T senso plus (80 lux).  I mounted it to the threaded eyelet on the left side of the M12 rack, using a Sheldon's nut.  I haven't ridden with this light yet; I'll report back on its performance compared to the Luxos U, which I use on two other bikes.  The tail light is a B&M Topline Plus.  I glued the dynamo wires to the fork and downtube with Shoe Goo (held flat to dry by zip ties that I removed later); I'm curious to see how it holds up.

The rear rack is a Tubus Logo Evo, and it's excellent.  I like how the pannier frames are lower and rearward. They protect the dynamo light, and they help the panniers clear my big feet.  The chainstays on this bike are only 17"/43 cm; it has NORBA race geometry.

Some original components remain; the seat post is Suntour XC, and the 48/38/26 Biopace crankset, headset, and brakes are Deore XT M730 (new Kool-stop pads).

I built this bike up for riding on gravel and dirt roads as well as commuting.  I changed out the original flat bar cockpit for Nitto B135 Randonneurs, and used a Nitto Dirt Drop 8 cm stem to counter the massive 24"/61 cm top tube and so I can ride in the drops.  

Unfortunately, this short stem seems to make the front end handle a little loose.  Probably just not enough weight on the front wheel.

I've wiped out my front wheel on occasion when trying to take twisty turns on loose surfaces, like singletrack.  But that's not this bike's mission (just an occasional dalliance).  I've considered changing back to a longer stem and some rear-swept bars like Jones Loops or Albastache, but I really like the low/forward riding position.  I just wish the top tube were 2 inches shorter so I could ride it even more comfortably in that position.

I'm using Tektro TRP RRL black/alloy brake levers, a Shimano 9-speed right/rear bar-end and a Rivendell Silver left/front bar-end.

In my bike stable:

The KOM (built with drop bars) was my primary gravel road bike until I bought a Foundry Auger (carbon frame cyclocross disc-brakes) this August.  The Foundry is much faster and more nimble, which makes sense considering it's only 65% of the KOM's weight (22 lbs ride-ready compared to 34 lbs) and fits me better.  

The KOM definitely provides a more comfortable ride than my carbon Foundry; that bike is very stiff and it beat me up until I adapted and rode out of the saddle more on bumpy stuff.

The KOM will live on as a commuter and tourer; it's easier to load up with the new eyelets.  It's still relatively fast and a lot of fun to ride around town; the KOM seems to like it when I bunny hop curbs and stuff on my commute, where my Riv prefers to cruise fast and smooth.

Cheers,

Tim Gavin

Cedar Rapids, IA

On Saturday, January 16, 2016 at 9:55:35 AM UTC-6, Lungimsam wrote:

pics!pics!