Vented Disks vrs Solid disks

[white exec]

Good luck with your metallurical analysis, then. I hope you are also equipped to be a competent 'expert witness', if it ever came to that.

[Stickyfinger]

Well I do work with Cast Iron and steels every day....
I do have original (old) Citroen C5 disks in a corner to compare to...
I do have confidence in my long history working with metals from my time with Stratec/Straumann (Swiss Metallurgical/Medical specialists) and over 15 years recently working with Cast Iron of various qualities from various sources.
The are many basic identifiers of quality/material if you know what you are looking at.

All in all, I do not think you will need a black tie or visiting form from the local prison....if they are s**t they do not go on, simple as that.

[elma]

I'd be confident enough to check a pair and assess the quality, I'm sure sticky can do it. A couple of gauges and a bit of know-how go a long way.

[Stickyfinger]

The "quality" of the casting can be assessed from the visual elements that have not been machined.
Colour of the machined surfaces
Structure of the "raw" parts.
Flash on the raw parts.
Evenness off the internal fins and their thickness/uniformity
The mould quality/material can also be assessed as well , its material imprint is replicated as is the method.
Temperature of the casting
Investment material/quality
Sound/tone
etc etc.

Cast items are easier than machined billet goods as they tell a story

[white exec]

OK. That's all more than I could and would ever tackle to evaluate low-price brake disks. There is so much fake stuff on ebay (including packaging, branding, documentation and engineered marks) it's a risk I am not equipped to take, especially with such a safety-critical part.
Very much a personal choice, of course.

[Stickyfinger]

You cannot make a casting lie, it has by its very nature got its whole story "imprinted" into it. As said, a fully machined part is a different matter as that has had its "story"machined away.

I will await the parts before I commit to their quality however

[elma]

Depends on your skills and experience though. I think I can tell too but I have the backup of several skilled engineers when I get puzzled.