This is my first build, I just had to do it because Blitzcrank is just too good for the sorry lack of creative builds. This build is a heavy utility build for blitz. He only turns into a tank late in the game, so beware of that if you're used to tank supports. The point of this build is to emphasize what I think puts Blitz on his own level; Incredible synergy with movement speed. This build has Blitzcrank flying around the screen in the 8-10 level range, aka the pre-teamfight-post-raw-lane phase. When mid and top stop roaming and dragons become hotly contested. Blitz thrives on landing his Q. One perfect Q can completely destroy an opponent's teamfight, make plays under a turret, change the game. This build makes sure that you can get in to position to Q shockingly fast.

That being said this means that Blitz is essentially useless on own with this build. If for some reason you end up alone you need to avoid a fight. By level 9 you'll be ridiculously hard to get cause you're so fast, but this blitz doesn't hurt.

That being said, let's get to it.

Don't throw the Q before level 2 unless you end up under a turret for some reason. Without communicating it to your adc it can end poorly. Especially against the thresh, morg world where if they survive they just lock up your adc. That being said the moment you hit level 2 things change. Q/E is enough at level 2/3 to make your bot lane super soft and sometimes even snap a FB. If you can land two of them in a row (assuming they don't have a healer) or land one under a turret it's basically FB.

Mid game you will be weak. Not squishy, but you're not trying to roll out on a Leona/Braum and expect to have equal footing. You're goal is to keep them afraid of the Q. You're always trying to land the Q on the ADC unless health bars dictate otherwise (or your under turret). This is where you use your speed though. You can force your lane by simply running down lane and if you can dodge the inevitable morg/leona stun attempts they basically have to run. You can make it to dragon, or mid lane, or help your jungle fast. Those boots of speed coupled with a W with even 2 points in make you a mid game speedy gonzalez.

Late game you basically can wreck house. If your opponent has really heavy CC you should be careful (a sentence that could be in pretty much every guide) because the early focus on utility means you'll never truly be a robotank. But against anything other than 3/4 champs worth of CC can't get you and almost no one in the game can catch you. This goes for your team. Use the Talisman of Ascension's speed buff basically all the time and Righteous Glory in any combat. Even if you're not chasing RG is great because it allows your ADC and MID to kite easy and the huge slow at the end of it just ruins opponents.

R. Use the ultimate as often as possible, it's cooldown is absurd. Keep in mind that at early levels the silence is not very long. I like to wait until AFTER the e has popped them up and they are about to hit the ground to use it. It should stop them from flashing out, often time completely because they don't mash the button, and gives both you and your adc another auto attack or two.

So this is obviously a heavy support roll in masteries. Get that movement speed. The AD masteries are strictly because I like to push minions under tower and the extra auto-attack strength in the early levels works nicely for that, it also helps if you land a level 1/2 Q or QE combo. You could easily swap these for Defensive masteries if you are acutely feeling the lack of tank.

Pros: Incredible speed/Zoning potential
Q can change fights by itself
R is always ready for every teamfight
Late game you can catch/run away form anyone and everyone

Cons: Early game you will NOT be a tank
Mid game you will NOT be a tank
High utility means low damage until late game.