We have two web spinning devices, one is web-caster gun which requires the air compressor. We also have the Webmaster 2000; it requires a good quality cordless drill or an electric drill (if you don't mind hauling the cord around) . The Webmaster is more portable with the cordless drill, which I really like. I think they both do a good job.
http://www.halloweenfxprops.com/webmaster-2000-spiderweb-cobweb-gun-spider-web/
http://www.halloweenfxprops.com/webmaster-2000-spiderweb-cobweb-gun-spider-web/