retrodude

I been into polishing old badly scuffed up parts for a couple years now, typically I get the parts for a good deal & I really like the results. In the 80s I leaned more the campy when it came to road components (still do) but always liked Shimano as well. I purchased a tri-color (600) to use on my road bike when I got tired of C Record friction (way back in the early nineties) and have come across a second tr-color since then, I'm using them both on some 90s mountain bikes. I always like Dura Ace but not as much as C Record. I saw an RD-7402 on Craigslist for $20 including a matching FD (don't really have a use for it) and jumped at it. I have 93' Kona Kilauea which has a smaller block freehub (23 max?) which is very light (around 23lbs) and thought it would be a great way to show off a polished old school Dura Ace RD (7 speed thumbies).
I'm surprised I never heard about the uniqueness of 7400 series Dura Ace rear shifting until now...
Funny how Shimano kept it Dura Ace incompatible with all other Shimano shifting for so long. Guess I could try one of those microshift 9 speed thumbshifters, or maybe just go friction! No biggie, it'll get used somehow.

Though I would share some of my handy work:
Before:


After:

Kekec1965

Man you do know how to polish...should've sent some of my stuff to you. I have three sets of DA 7400, 7402 is 8 speed and you can easily use 9 speed downtube shifters such as these with it, just not having 9th gear. link HERE

If you are after a brifter set, they can be a tad expensive though, but sometimes they pop up in Europe for less than 100$

Good luck

repechage

The reworked mechanism appears to have the black cartouche depressed and filled with paint around the text- the originals I have have that black area equal to a silk screened region...

how was that area controlled?

SurferRosa

I'd like to see this on shag carpeting with a pillow or scarf, maybe some sweet soul music in the background.

tmi?

retrodude

Good question, I'm curious to know what Shimano did here. It's possible they have raised letters in the aluminum with some sort of dark fill surrounding them. It's a very unique detail I can't say I've seen on other RDs. Much nicer than a silk screen logo.

I wasn't sure how it would react so I applied a super sticky rubber tape over it during the chemical anodization removal process to ensure it was not in contact. For the sanding I simply used green painters tape cut precisely to cover it.

Definitely worth protecting!

retrodude

Yup, kind of qualifies as bike porn

retrodude

Thanks!!

Takes a lot of patience, thanks for the tips, still undecided where to make use if it, maybe just set it next the the wives silver (LOL)?

SJX426 

There are DT shifters too.
P1010726, on Flickr

retrodude Terrific job on the clean up. I have passed up on a lot of RD's with that kind of road rash. I would be interested in knowing the steps you took from beginning to end.

retrodude

I can't take full credit for these steps, I use most of the procedure in this link: https://theradavist.com/2009/10/tuto...bicycle-parts/, basically clean/degrease the component then remove the anodization, I use Zep commercial industrial Purple cleaner available at Canadian Home Depot, it's not as harsh as drain cleaner and works well. Then proceed to remove any deep scratches, sometimes a fine file is needed or 150 grit sandpaper. Then move to a 300 grit. Once you have all the scratches which 600 grit wet/dry sandpaper cannot remove taken care of move to the 600 grit. I use it wet within a sink with sometimes hot running water. Then move to 1000 grit wet/dry followed be 1500 grit wet/dry. I usually finish with a very light rub using SOS wool soap pads under hot water. The next step is fairly unique (see link), using cotton balls and Simichrome polish finish the job. I had to order the Simichrome on-line as I could not find it for sale in Canada. I have used this for derailleurs, cranks and seatposts with good results. There will be a concern that the aluminum is unprotected afterward which is valid. My bikes are kept indoors and kept very clean so it has not been an issue for me even a couple of years after the fact

SJX426 

retrodude Thanks! I have a couple of old parts that are not anodized that I hit with Mothers every several years. All my bikes are kept in climate controlled environment when not in use. It works.

masi61

A lot of very ugly clear anodized silver, road rashed parts could be rescued if more folks would embark on some of your procedures!

SurferRosa

Interesting choice as a deanodizing agent that I haven't heard before. Looking at Zep's huge catalogue of products, I wonder if that's the best choice. Do you mix it with hot water?

dedhed

Check with motorcycle shops and golf shops for simichrome.
A coat of auto wax helps keep the shine

Charles Wahl

Impressive. The $64,000 question is: was the derailleur disassembled to do this (removing the pivot pins)? If so, how, and how was reassembly done? If not, then how to keep abrasives out of the works (the pivoting parts that wear against each other)?

retrodude

I just use it full concentrated form (no diluting), I had dabbled in removing anodization years ago with drano and always worried it was too corrosive, I feel this works just as well at full strength and appears to do no harm, I always try to remove all rubber or plastic parts

retrodude

The derailleur was disassembled to it's smallest parts excluding pivot pins (I would be scared to try). Basically the three parts to go into the Zep were inner & outer pulley cages and the main body with logo protected (just to be safe). I make sure to rinse everything thoroughly in hot water after a couple minutes in the Zep bath.

retrodude

Thanks for the tip, my tube of simichrome is getting pretty used up

Miele Man

Beautiful!

I have a pair of Shimano Exage clipless pedals that I was able to remove most of the grey anodizing from by carefully scraping it with a very sharp knife. I then use various files to remove the mold seam lines and to give the pedals a better contour. I then used various grits of wet/dry paper and polishing cloth by hand to give the pedals a high lustre polish.

This was the result.




Would the stuff you used to strip the anodizing harm the springs inside these pedals or the rsin or hard plastic end piece that pivots?

Thanks and cheers

retrodude

Wow! it looks fantastic already, nice work. If there is still some anodization lurking in corners for example that you want to get rid of you could try dipping them. The springs should not be a concern but the plastic parts may be, I am unable to say for sure. I always rinse thoroughly once removing an item from the bath. One thing to note is that the de-anodizing solution will leave a duller finish initially, and in some cases leave a dark grey coating. This coating comes off pretty easily with an wet SOS pad though. You will need to spend some time re-polishing. You may want to consider avoiding the de-anodizing solution unless there is still enough anodiozation remaining to warrant the effort, good luck!

lajt

Dumb question: Why do you need to remove the anodized coating to polish it? The anodization is a protective coating, right? But I'm guessing it's hard and resists being rubbed smooth, I guess?
What is the drawback to removing that coating, it's more prone to scratching? I assume rust isn't an issue since it's aluminum.
Sorry I'm jumping in so late to this discussion, I'm just so impressed how you can bring an old part back to life like that.

retrodude

No dumb questions here if a part has lots of scratches and filing/sanding is required to smooth everything it its best to go back to the bare aluminum. I believe some anodization has the ability to be polished to a degree but in some cases if bits of anodization are unsanded it could be noticeable so best to be all removed. Anodization certainly is less prone to scratches and protects aluminum from corrosion, if left out in the elements a polished bare aluminum finish would become dull over time. Lately I have tried just using a bit of Mothers Mag Aluminum Polish on anodized but old and dulled parts with good results, another option if not too scratched up.