polishing technique

[kaiser]

I just bead blasted a set of Syncros cranks today at work, so I'll be spending way too much of my evening polishing. Not sure how it will go with them being steel, but we'll find out soon enough.

'Guin

I had heard blasting was a bad idea, leaving the surface harder to polish i.e. not changing the properties of the material, but was a step back as far as finish was concerned. Anyone know for sure?

 

[Pickle]

I have used T-Cut on the RTS with good results.

However, Brasso has provided amazing results, and after 3 application/buffing sessions the RTS is about back to its former glory

 

[pinguwin]

I had heard blasting was a bad idea, leaving the surface harder to polish i.e. not changing the properties of the material, but was a step back as far as finish was concerned. Anyone know for sure?

I passed it by the guys in the paint shop and a mechanical engineer who is a serious cyclist and it won't harm the metal according to them. Sand blasting will, bead blasting won't.

It does leave a matte finish which has polished up reasonably well. It it a little harder to polish than say a set of Al cranks but I'm not sure if that is because of the bead blasting or because of it being steel. The paint guy took out a knife and scraped the paint and it hardly scratched and said that it was pretty resistant to most strippers.

I'd be interested in finding out more.

'Guin

 

[kaiser]

I had heard blasting was a bad idea, leaving the surface harder to polish i.e. not changing the properties of the material, but was a step back as far as finish was concerned. Anyone know for sure?

I passed it by the guys in the paint shop and a mechanical engineer who is a serious cyclist and it won't harm the metal according to them. Sand blasting will, bead blasting won't.

It does leave a matte finish which has polished up reasonably well. It it a little harder to polish than say a set of Al cranks but I'm not sure if that is because of the bead blasting or because of it being steel. The paint guy took out a knife and scraped the paint and it hardly scratched and said that it was pretty resistant to most strippers.

I'd be interested in finding out more.

'Guin

I can imagine the coating on the syncros cranks, very tough. I do recall there being different types of medium for blasting with sand(if indeed its still used today) being particularly abrasive. Wonder how the professional metal finishers go about it. I have a blast cabinet available to me as well as pillar drills and air tools, just don't do much polishing to the stage.

andy.l got to say your method looks good after those pace forks, how would you rate the finish? Polished, mirrored etc.

 

[pinguwin]

Wonder how the professional metal finishers go about it.

The guys in the paint shop said that the bead blasting is much gentler and the material is much finer than that of the sandblaster they had. They sandblast stuff the size of a room, so they have a pretty industrial grade setup.

A guy at my work is a bike collector of the level where I've heard the Smithsonian Institution has contacted with an interest in some stuff he had who told me to avoid metal finishing shops like the plague. He said that they generally use pretty heavy-duty equipment that doesn't sit well with the thin-walled material and it really is best to finish it yourself. That's his opinion and I suspect he knows more than I do.

 

[scant]

I'm no expert, but theres definate different grades of "sand blasting" with even walnut shells being used (pretty soft apparently)

without wanting to appear overly stupid, how are you supposed to use the polishing parts on a dremel the small polishing wheel appears too hard & on practise attempts didnt appear to do much in the way of actual polishing?
BITD in school I scotch brited an old seatpost & put that on the polishing buffer & within a few minutes it was mirror finish! would be nice to get that effect again without the hours of elbow grease (although i appreciate the elbow grease gives even better results

 

[cherrybomb]

You need to use the cutting paste that goes with the dremel buffing wheels.

 

[Dr S]

Machine Mart do an el cheapo bench mounted 240v grinder for about 30 smackers, a polishing mop and soaps will cost a few bob more, slap them on, turn up the Zep and get polishin, saves hours it does. Autosol and old terry towelling does a to notch jod on the smaller stuff IMO

S

 

[scant]

You need to use the cutting paste that goes with the dremel buffing wheels.

yeh I thought that, but it comes in the smallest pot in the world & the dremel attachment can be angled to touch the contents! am I missing something vital?

 

[Bikebuster]

Can anybody explain me the part of the 'elbow grease' :?: Looked it up on the web and find that it is a sexual lubricant :shock:
I am liberal of mind, but this is interpreting my 'hot rod' a bit to literally