Bicycle Mechanics - Buying Used Carbon Fiber Bike- What to Look For?

I'm looking at buying a 2006 Giant OCR Composite 3 and once money changes hands, I'm stuck with it.

What I can't seem to find are any web pages that tell what to took for so if you know of any, let me know.

I can visually inspect a framset for scratches and gouges but I need to know what parts of the frameset- top tube? seat stays?- usually have the most damage from crashing, falling over, etc.

Also, how deep of a scratch or gouge is considered to compromise the integrity of the frame? 2mm deep? 3mm deep?

Last, are there areas of the frameset that are most easily compromised by a scratch, like the bottom bracket or head tube areas? What part of the frame, if already damaged, would most likely catastrophically fail when I hit a pothole or when sprinting out of saddle?

Thanks.

How much are you saving from a new one?

Is the risk worth it, in the long run?

You will never know it's history.... so buyer beware. As you noted, once the cash flows, it's yours.... and there ain't no repairing it.

Probably saving $1000 from a new one as the Defy Alliance 1, the replacement model, costs about $1800, before tax.

That makes the risk more worth it, esp given that even though I am very confident the geometry will work for me- it's very similar to my current road bike's geo- I won't know if the fit is right until I've ridden it several times, IOW until I own the thing.

The bike in question (http://sfbay.craigslist.org/pen/bik/1179840058.html) is silver in color so I figure that in good lighting, I'll be able to see any defects pretty well.

Hmmmmm.

Three things I quickly found

1. http://thecycleway.com/?p=111

2.
Inspect your bike. Carefully inspect all surfaces of your bicycle, paying special attention to high stress areas like tube junctions, especially the down and head tube joints, the handlebar, handlebar stem, seat post and fork. The entire length of the fork should be inspected with particular attention to the dropouts and crown area.

Look for scratches, dents and gouges, as well as signs of hairline cracking, delaminating of carbon fibers, or separation; as any of these may be early signs of damage. In addition to these visible warnings, any squeaks, creaks or chirps should also be considered warning signs of potential failure. Most dents, dings and scratches are cosmetic and most noises are related to dry surface friction, but in all cases, you should refrain from riding the bicycle until a determination regarding its safety use has been made.

3. http://www.bikepeddlergreeley.com/carbonfiber.html