Managed to write off my rear wheel last Sunday (fsa xc290) on my scandal. They don't seem to be the greatest, or maybe I was just unlucky. Anyway, can I use all the spokes to build up another wheel or will they have stretched too much?

I doubt if the spokes will have stretched much, but different brands of rim all have slightly different diameters, so unless you're changing like for like there's a good chance you'll need new spokes anyway.

Didn't know that! How do I go about finding that out then? Been looking at stans arch replacement for the fsa rim

There are a few spoke calculators online, you put in the hub, number of spokes, rim and lacing (ie 3 cross) and they calculate the length of spoke for the left and right sides.

more likely that the spokes are the weak link than the rim?

Try the spoke calculator over on http://www.dtswiss.com/

You'll need to find out some info on your rim and hub from their manufacturers website to input and it will give you a spoke length.

As above, so long as the new rim is similar (say within 2mm) to the old one then it should be fine. I'd happily reuse the spokes so long as they didn't get bent or run loose for a long time.

Depends on a few things.

Will they fit? The ERD (effective rim diameter) might be a couple of mm different but might not make as much difference as you think.

What spokes were they? If they're cheap and nasty, why reuse them? Take the chance to get some Sapim or DT.

who built the wheel? Built well mean more chance of reusing spokes. If the wheel was mashed together then some spokes will have been working hard while some would have been not doing much while the wheel was running. Someone may have bent the spokes around more than was needed when building the wheel.

How did the wheel fail? If you flat spotted or cracked it, maybe they can be reused. If you landed sideways and taco'ed the wheel, too much strain may have been placed on some spokes to make it worth reusing.

I've swapped rims and hubs about before and reused DT spokes that I'd built with originally and things have been fine.

slight egging of the rim and significant buckle within a quarter turn – still runs through the frame though. it was a factory wheel FSA XC290. – had a look on their site but there doesn't seem to be any info on spoke length. it just says hub had medium flange?

There's online guides available that tell you how to measure the hub flange, rim width etc and how to plug it all through an equation to give the correct spoke length.

Personally though I wouldn't bother, it's easier building with new spokes and rim, I hate re-using (although I've done a few rim swaps in the past and never had any problems but they were customers wheels!)

I had a wheel build recently using spokes from a 3 year old wheel.

It's absolutely fine.