Is there a rule about mixing different fabrics within a quilt? What I have is several skirts (medium wt), some trousers (mid wt?), and a silky feel dress (it's seen many incarnations). I'd like to do a traditional or perhaps a BOM. What should I look out for? Any help gratefully excepted :P

One more question, when doing a BOM or mystery, how do you decide what fabrics to use (decide as you go or plan in advance)?

First decide if this is a quilt that will be washed often. Then determine if the fabrics will hold up to the intended use/laundering.
Then I pick and choose what will go into it :D:D:D

I've always chosen my fabrics for mystery quilts based on the first instructions about fabric choices.

I agree about making sure what you are going to use the quilt for. Then I always try on a BOM to pick out all my materiasl and I put them in a plastic container so they do not get mixed up with other materials. Make sure you pick out more than you will probably use but that way you have a good selection to choose from.

I doubt there's a rule, but mixing a thin, silky fabric with medium weight fabrics might not be a good idea. Save all your silky stuff for one project and recycle all the medium weight fabrics for another. It's fun to recycle and reuse. I can't wait to see what you create.

That was my thought too.

If I am going to put all the work and time into a quilt. I surely will not mix fabrics., unless it is a crazy quilt block that is designed for this kind of mixed fabrics.

I'm thinking I want to use these fabrics for Rhonda's Sampler. I just need to find a few other fabrics.

If you use silky (thin) or stretchy fabric along with the firm weaves, then I would suggest to sew them on a foundation piece (muslin). It would stabilize the stretchies and give the skinnies some body. You can also incorporate ribbon and trim if you want to go more along the crazy-quilt variety.

Okay, this is what I'm going to do. I'll save the lovely white silky for another project. I'll use the medium weight fabrics in the BOM. Thanks so much for your suggestions and advice. It was very helpful. I think this is gonna be funnnnn!