I covered duct board in cloth and now want to hang them on the walls. How might I mount them; the material is not strong enough to hold it's own weight w/ ony screws thru it and the boards are a bit warped. Thanks for any ideas.

You want to make a fame that surrounds it, think of a picture frame.

I made something like you are thinking using Ecophon acoustic panels, surrounded in a wooden frame, THEN covered in fabric. I could easily screw into the wood frames to hang them, but in my application they are from floor to ceiling. So I anchored them at the top and bottom with metal 90 degree brackets.

Check out what I mean:
http://www.tekmil.com/theartek/pages/IMG_7009.htm

And with the fabric:
http://www.tekmil.com/theartek/pages/IMG_7182.htm

I covered duct board in cloth and now want to hang them on the walls. How might I mount them; the material is not strong enough to hold it's own weight w/ ony screws thru it and the boards are a bit warped. Thanks for any ideas.

This product seem like a solution for you....

Acoustical Panel Fastener (http://www.cinemabuilder.com/products/construction/acoustic-panel-fastener.asp)

Z clips, such as these, can also be used:

http://www.monarchmetal.com/pages/panelclip.html

Regards,
Terry

I basically did what TekhouseE did on a smaller scale and it works great, you just have to be careful installing them that you don't rip the fabric too bad and don't split the wood if you screw into them (which is what I did because my panels are a lot smaller than his.)