Posted this on VJMC site ... maybe someone will share knowledge with us !

[AshimotoK0]

"Anyone know a technique for reproducing the clear coat 'brushed' alloy finish, particularly on fork legs. The best I have seen is on the 'Vic World' CB750 sandcast rebuilds (one of which is in the Honda Museum in Japan). I read a VJMC article a few years back about sanding with different grades of abrasive paper and sanding 'with the grain' on the alloy. Vic Worlds technique is 'listed' in this photo but no real detail. 'World 1) strips the clear coat then 2) they are bead blasted, 3) rough polished cleaned with solvent, 4) dipped into an ultrasonic bath, 5) Acid bath so that paint will 'stick' 6) Dried 7) Painted with a special clear coat. Its 3) the rough polishing that I need to master plus I can only assume the 'Acid' described is Chromic acid (as in 'Alodyne 1000 series) use in the aerospace industry, active ingredients Chromic acid < 0.5 % and Zirconium potassium fluoride < 0.5 % ). I wonder if the 'special' clear coat he uses is something like 'Eastwood Diamond Clear'. Please don't remind me about the health hazards involved... as I am fully aware. BUT I hate highly polished alloy on Honda's IMHO it just doesn't look right. I have heard of people using a Scotchbrite 'satinizer' wheel to recreate the brushed finish. Problem on fork legs are the protrusions for caliper mounts/mudguards 'fenders' etc. Even thought of mounting the leg in my lathe but powering the drive from a separate stepper motor so that in the 'protrusion' areas it will only rock in a pre-programmed arc. I have 8 Honda's in various stages of restoration so I have 16 fork legs to refinish. Hence, I need to definitely automate this process somehow.
Why can't the 'Classic' mags include stuff like this instead of the same old tosh that they they expect us to stump up our hard earned cash for every month?"



http://www.worldmotorcycles.com/Pages/MC-Retro-Article.html



[ Guests cannot view attachments ]

[Johnwebley]

  thanks for posting this,and the link,it goes to show the depth of detail ,and how carefully he does the re-build,not over restoring ,

 it would be great to live in Arizona,or Southern California with the dry atmosphere and little,if any salt on the roads

[Nurse Julie]

I am just being taught the fine art of polishing cast alloy casings etc on bikes to show standard. Now, I know about polishing 'with the grain' on wood but, as hard as I look at this alloy side casing, I can't find the damned grain anywhere, where do I look???

[mike the bike]

That thought occurred to me too

[UK Pete]

I dont think ally has a grain, it is usually wise to polish in the direction that the factory polished in so a sort of man made grain ,if you get what i meen
pete

[AshimotoK0]

If you scroll down this mega download there is an old VJMC article. (in fact there are loads of useful articles).

https://www.dropbox.com/s/anpzqn2r55f1o9k/CB750%20Mega%20Parts%20Service%20and%20More.pdf?dl=0

It's here: in jpg format:

[ Guests cannot view attachments ] [ Guests cannot view attachments ]

[K2-K6]

Looks like the reference to "grain" is the finish pattern put on at the factory in leaving the linear marks in the casting and lacquering over to give that brushed look instead of polishing.
As you say Pete, you're certainly not aware of grain in the metal when working with it and you'd probably need a scanning electron microscope to see grain in many metals.
Saw a program on renovating a De Lorean car and they had a guy in that specialised in that brushed finish of the stainless steel body panels that was original to that car........which reminded me that the stainless industry routinely finishes products in that brushed fashion, so could be some sort of automation used in sheet works (industrial kitchens) or things like cutlery manufacturers that may give you some practical leads Ash.

[JamesH]

This is the 3M scotchbrite system they use to refinish brushed stainless

http://youtu.be/XBdSzdndKkg

[Trigger]

Wasn't the VJMC responsible for awarding the 'Best 1970's Bike' to a 1980's bike at Sammy Millers last year??
Shows how much they know 

[Green1]

Ha forgot about that was it a z1000?

[Trigger]

Ha forgot about that was it a z1000?

Can't put my finger on it Mick but, it was later than the Z1000. Have Z1300 in my head for some reason but, I could be wrong. It will come to me.
Had a big disagreement with VJMC some years ago after I sold a very early CX500 single disc, out of the crate. VJMC told my customer that the bike was the wrong spec with a single disc, and he was believing them. A few words were exchanged on that one 

[Green1]

Z1300 rings a bell what a fugly brute they are.
Well we all know you know nothing about the CX 

[Trigger]

Z1300 rings a bell what a fugly brute they are.
Well we all know you know nothing about the CX 

Don't tell them that on the CX500Forum