Many people build Blitz with AP items. But I see no reason that why he isn't played with attack speed/crits build. He can just pull the enemy, silence him, knock him up and AA the guy to death with his MS/AS boost.
Wings played a bit of AD blitzcrank in season 3. It's nothing compared to a lot of other tops, but it's fun as balls and not that awful. You don't go any attack speed or crit, though.
dorans shield->boots->bottle->triforce
Then, max out your cdr and get tanky stats. All you need for dps is the triforce. Try a spirit visage and a sunfire cape after, and then maybe a shiv or something. consider standard 15AD page, but I can see lifesteal quints working.
Meiyjhe is quite right in that it's hard to 1v1 most meta tops, but when your jungler pops out and you W at them, nobody will survive that. And also you can hook them into tower.
Blitzcrank is a CC heavy champion, but not a damage heavy one. Blitzcrank is in need of an ally in his lane in order to have any power whatsoever early game. As a solo laner, he would be way to turret dependant and can only really shine when the jungler comes by to gank.
After the early game phase, he can be a great threat to the enemy team (if you actually succeeded) due to his hard CC and damage output (if you would build him AD), but you can do that as support these days as well. Top lane AD Blitz overal feels like a handycap, if you want to play Blitz somewhere else I'd suggest playing him jungle. He isn't that great there either, but at least his ganks are amazing :P
Fnatic Soaz played him solo top in Season 2. But he played him like roaming AP CDR support offtank if I remember well. Blitz benefits from Mana and AP.
Wings played a bit of AD blitzcrank in season 3. It's nothing compared to a lot of other tops, but it's fun as balls and not that awful. You don't go any attack speed or crit, though.
dorans shield->boots->bottle->triforce
Then, max out your cdr and get tanky stats. All you need for dps is the triforce. Try a spirit visage and a sunfire cape after, and then maybe a shiv or something. consider standard 15AD page, but I can see lifesteal quints working.
Meiyjhe is quite right in that it's hard to 1v1 most meta tops, but when your jungler pops out and you W at them, nobody will survive that. And also you can hook them into tower.
Just be careful of impossible matchups.
He needs CDR for his abilities to be effective, he has some good AP scalings and he is mostly played as support.
^Some reasons, why not.
After the early game phase, he can be a great threat to the enemy team (if you actually succeeded) due to his hard CC and damage output (if you would build him AD), but you can do that as support these days as well. Top lane AD Blitz overal feels like a handycap, if you want to play Blitz somewhere else I'd suggest playing him jungle. He isn't that great there either, but at least his ganks are amazing :P