Full Clap Malphite is a build for when you want to have 400+ armour and still one shot carries.

As with all Malphite picks it's recommended as a counter to a heavy AD team but can still work against almost all teamcomps.

Precision

Press the Attack
This rune gives so much damage to Malphite's empowered auto attacks and is pretty easy to activate once you've gotten Titanic Hydra alongside the attack speed with Trinity Force and Legend: Alacrity.

Triumph
Great for surviving close 1v1's and huge teamfights.

Legend: Alacrity
Lets you clap enemies faster and is great with Press the Attack.

Coup de Grace
Your upfront burst from Unstoppable Force, Ground Slam and an auto attack will take squishies below 40%, this helps you finish them off with the next couple of auto attacks.

Sorcery

The Ultimate Hat
Malphite is very ultimate reliant so this is a great rune on him. You can consider swapping this for Manaflow Band and maxing Seismic Shard if you have a very rough ranged lane match-up.

Transcendence
With this, Trinity Force and an Abyssal Mask you can get to 40% CDR, putting that all important Unstoppable Force on a low cooldown.

Starting Items

Corrupting Potion
Take into even or good melee match-ups. Gives great sustain and a little bit of damage. Very useful for allowing heavy trades in lane.

Doran's Shield + Health Potion
Take into ranged or bad melee match-ups. Helps negate ranged harass. This in use with your passive shield should let you farm against rough match-ups. The bonus health can help you survive an all in from the likes of Renekton or Darius.

Early Game Items

Phage
Rush into melee match-ups. The stats and passive help you in long, extended trades which you want against melee match-ups.

Sheen
Rush into ranged match-ups. Spellblade helps with short trades you want to be having against ranged match-ups. The additional mana helps with poking using your Q or using spells to last hit if you're having a rough time.

Boots
Try to fit these in before finishing Trinity force.

Mid Game Items

Trinity Force
If you're even or ahead when you get this you should be able to 1v1 anyone if you play it well. Try to space out your abilities when fighting to get the most out of the Spellblade passive.

Titanic Hydra
You definitely want this in your build but if needed you can delay it by one item. Get it after Trinity Force if you're against immobile enemies and you're even or ahead with your lane opponent.
Once you've built it make sure to utilise the active. Make sure your Brutal Strikes is active and use it as an auto attack reset (use it right after you've hit an auto attack). You can do this after hitting someone with your Unstoppable Force and have Press the Attack activate before they hit the ground.

Dead Man's Plate
Get this if you're falling behind and your lane opponent is AD or if the enemy is very slippery and you can't stick to them. The momentum auto attack helps keep them in place for an extra few claps.

Abyssal Mask
I rarely build this second, but if you're against a heavy AP team and are falling behind it is a good buy. Substitute this for Adaptive Helm if against a strong Teemo or Cassiopeia.

Late Game Items

Sterak's Gage
Great if you're a tiny bit of damage away from one taking down their carry in a teamfight. The additional base health gives more damage to your spellblade and the shield will give you time for an extra clap or two.

Guardian Angel
If you can one shot their carry but then get killed by the rest of them pick this up. You can still get your combo off on them and have your team clean up while your busy reviving.

Thornmail
If you're having trouble against someone like Master Yi or Jinx pick this up.

Randuin's Omen
Strong against champions like Vayne and Jax who rely on auto attacking multiple times. The active helps for keeping them in clap range too.

Abyssal Mask
Good pick up if you didn't grab it before. It caps out your CDR and the MR shred is good for your team and your abilities.

Adaptive Helm
As said before really effective against the likes of Teemo and Cassiopeia.

Seismic Shard
Take this level 1. Put a few early points in it if you're in a rough ranged match-up. If enemies are very slippery max this second, otherwise max last.

Brutal Strikes
Take this level 3. The bread and butter of Full Clap Malphite. Max first in almost all cases.

Ground Slam
Take this level 2. Max either second or last depending on what you're doing with Seismic Shard

Unstoppable Force
Your Ultimate, level this up whenever you can!

Levels 1 - 5

Against Melee Match-Ups

It's quite difficult to force an advantageous trade pre-6 as Malphite. Only initiate if the enemy uses either their escape or their CC on the minions, e.g. Dr. Mundo using Infected Bonesaw or Maokai using Bramble Smash.
If you see them do this you have a chance to use your Seismic Shard to steal their movespeed and go for a trade. Activate your Brutal Strikes as you being your auto attacks and only use Ground Slam when they turn to fight.

It is much easier to bait the enemy into taking a bad trade against you. Play passive in the early levels, only poking occasionally with your Seismic Shard while last hitting. When the enemy initiates the trade use Brutal Strikes and Ground Slam to reduce their damage while you clap them. Save your Seismic Shard for when they try to run. You should have activated Press the Attack by now and with practice you'll know if you can chase for a kill.

Against Ranged Match-Ups

Malphite has a pretty rough time against ranged match-ups. Put a couple of points in Seismic Shard early and ask for ganks. Try to poke with Seismic Shard while utilising Granite Shield as much as you can to negate their side of the trade. Mainly focus on farming minions until you hit level 6.

Level 6+

In a 1v1 do not engage with Unstoppable Force unless you can 1 shot the enemy. Instead try to gap-close using Seismic Shard and give them a few claps. When they use their escape or Flash follow them with Unstoppable Force if you think you can get the kill.