Pokemon Black/White help: Will I find a shiny deino eventually?

I have seen a few videos up on youtube of people catching 100% legit shiny deinos they encountered randomly after roaming around victory road hours at a time. I realize the chance is 1/8129 x the 20% appearance rate of deinos. I have tried roaming around without repels (over 1,000 encounters so far ) with no luck. I have also tried using repels and keeping a regular level 38 deino in my first slot with even less luck. Will I come across one eventually? And, how exactly do I do the "repel trick" properly?? All I am attracting is durants. Then ofc my deino is too weak and I have to send out my other pokemon which get injured.