Dont do it. redirects should be used only for legitimate site moves or for blasting spam to. If the site your are redirecting has a penalty, it may pass on to your money site over time (could be weeks, could be months)
If you are using a fresh domain and building natural looking backlinks to it then its a little pointless as you could just build them to your money site
can you explain this more? blasting spam to a redirect? What does that do? You blast spam to a url that redirects where? Why?