A hop spider are useful because they allow you to have your hops roll int he boil, but you can still stain them by simply removing the bag. I've always used muslin bags for hop additions, but I decided the next time they wore out I would make a hop spider. So, when my buddy Andy called saying he'd beaten me to the punch, I ran over to Ace to pick up materials.
A 4 inch to 3 inch reducer ($2.99)
A 3 inch hose clamp ($1.29)
Two 20 inch lengths of 1/2 inch CPVC (from the 10 feet I already had)
a 24 inch nylon bag ($7)
I cut two 1/2 inch holes in the 4 inch to 3 inch reducer so I could put the 1/2 inch CPVC lengths through. Lastly, I put the nylon bag over the reducer and tightened the clamp. Getting the bag completely on the reducer took some bunching, but it's not hard.
There you go.