Restoration of a Rock Shox Mag 21 Sl Ti including color

coyut

Mountain Cycle Fan
I'm in the process of restoring a Rock Shox Mag 21 SL ti to its original beauty.
I'm going to share the process as I had some learnings on the way.

This is a pic of the fork that I bought for my project.

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First step was to strip the fork down.
The Mag21 tools are very rare these days (let me know if you got a set to buy ;))
I had to find anothert way to separate the upper and lower tubes without the official seal puller.
The main steps are well documented but without the seal puller the only way to separate the fork legs is by removing the clip ring and pressurizing the fork until the legs separate.
I did release the air, removed the oil and then removed the clip ring.
After that I clamped the upper legs back into the fork crown, which I have secured in a work bench.
I also placed a big bucket with towels inside pretty thight to the lowers.
Towels also went around the seal area, as it will get a pretty mess without them when the legs separate.
I pressurized the legs until the seals popped out. Be aware that the lowers will shot away like a rocket !!! This is why I had a bucket with towels inside to catch the legs without flying around.

If you are going to try this do this on your own risk !
If you are not knowing what you do it can get very dangerous !!!!

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I wanted a long travel kit to extend the travel from 46 to 60mm, just like I rode myself in 94.I
found one online, but you can also shorten the original top out sleves to created your own LT set.
If you are going to shorten them, then use precise machining to do so.
The original full kit also includes some different springs, but they are not absolutly needed. I will add them once I find them.

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It also took some time to find a internal service kit.
Oil seals are still available from Enduro but NOS wipers are rather hard to find.
ebay is your friend sometimes for them as well.

SRP still sells the air seals. I will order some from them.
 
I had a rather hard time to find a way to restore the original gold mirror finish.
So I tried to get some knowledge how Rock Shox did it 1994.
Back then the Magnesium legs were mirror polished and afterwards coated with a clearcoat that got a little bit of color added.
So they had a honey look clear coat to apply. Togehter with the mirror underground they created the mirror gold look.

Since Magnesium is pretty corossive they had the problem of oxidation over time. A reason why all the SL21 lost their shine and look very odd greenish theses days. Scratches in the coating sped up this process as well.

So my first Idea was that there must be a modern way to apply a gold coat and solve the oxidation problem.
Sadly Magnesium is very tricky. I talked to a lot of specialists who do coatings as their daily business. Ti nitrate, Anodizing etc. will not work with Magnesium. There is a way to apply a special color first that will allow to apply some gold coating afterwards.
Its also possible to use a special paint.
That color is called candy color. But finding someone who was willing to coat it with gold candy color was rather hard to find, as its very tricky to get a perfect finish. A black color coating is also needed in advance. Many painters have played aorund with it but stopped using it due of a high risk of failure in the coat. The liquid color is also pretty expensive and pushes the cost.

Since all options I found involved all needed steps, which are needed for a original restoration, I decided to go the original route.
So getting rid of the original paint, polishing the legs and paint them with a tained clear coat.
 
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After a lot of off and online research I found a specialiced company that will coat them with the honey coating.
They call it clear gold. They use the exact process to supply painted parts for high priced de Sede furnitures. So they know exactly what they do.
I will be able to pick up the parts in about two weeks. The samples I saw looked extremely well. So I'm very exited to see the final result on my fork legs.
 
Btw. I wanted to get the exact fork setup as I raced in 94.
Back then I used a turquise AC fork crown on my Sl21 ti fork on a Mountain Cycle San Andreas.
So it had to be a AC crown again. Some will argue that a original setup should be prefered for such a restoration, but I just want to rebuild what I rode back then.

I was very happy to find the exact model I was looking for here on retrobike. Actually in a pretty good shape. Just needs some cleaning.
The black one jumped me on the hunt for the turquoise one, but was in false color for my project . The black one went now to a friends project bike.

;)
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I also found a crack in the original Magnesium brake arch underneath the paint while stripping the paint.
So I had to find another one. I thought a AC would be a nice addition to the AC crown. But for know I only found a NOS Brodie one. I might think about the AC whenever I find one.

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