What qualifies for a sticky?

Just want to know what qualifies a thread for a sticky?

The HAMB Model Car social group does a build-off contest every few months. A theme is chosen, and members of the group have 3 months to finish thier entries. After the deadline, pics are collected & a poll is set up on the main board where we ask the HAMB to vote for thier favorite of the bunch. People donate prizes that go to the favorites.

Its a lot of fun for the social group, & there's a ton of people who enjoy seeing what the groups members are capable of.

This time around we asked repeatedly for a sticky for 5 days, just to keep the thread at the top where we can get as many votes as we can. We all know how fast a thread can drop off the first few pages, & its simply hard to get folks to see what we've done & give them a chance to vote.

We never did get a sticky for the thread, & we had to bump it up a crapload of times. I was told that really, only auctions get a sticky, with the exception of something like the "stolen truck" thread recently.

BUT- every Friday, the artists get a sticky for thier "Friday Art Show". So I'm just wondering what the Model Car social group has to do to qualify for a 5 day sticky once every 3-4 months or so. Seems we're just as creative as the guys in the Fri Art Show thread.