KF2 Firebug Guide: Caulk n' Burn, Tap Fire and Crowd Control

The author wrote this when the Survivalist perk was still unreleased, calling the Firebug build with a Caulk n' Burn "the Survivalist before it exists" because it leaves so much space for other weapons. All figures come from the community stats spreadsheet. For other Firebug approaches see the perk overview pages in this database.

Know your role

The Firebug is the best trash killer in the game, with strong crowd control from a Caulk n' Burn alone. That lets you:

• kill all the trash;
• guarantee an escape route;
• carry off-perk weapons to partly fill missing roles (never a replacement for a real medic);
• generate dosh for the team because you do not spend much;
• peel ZEDs off teammates;
• act as an "indestructible door";
• permanently disable the abilities of medium trash ZEDs.

What you cannot do is fight large ZEDs. Panic, microwave pushback and stumbling are possible, but unless you can actually kill them, or teammates do not need headshots, you harm the team.

What to do

Tap fire. For 0.35 seconds after a tap you can deal damage without consuming ammo. Spray weapons burn about 857 ammo per minute, so 0.35 s is about 5 free ammo per tap, against a minimum of 4 ammo (3 for the Microwave Gun) per tap. In effect you increase ammo by 125% and reduce ammo cost by 55.56%.

Sprint all the time. Finishing a tap while sprinting creates a flame wall rather than a small spot, which means much more ground fire.

Aim for the feet. You deal impact damage and create ground fire, and you do not block your team's view.

Do not attack large ZEDs. Scrakes and Fleshpounds take only 30% damage from fire.

Get close to Husks and Sirens. It is not suicidal: Heat Wave gives you insane crowd control. Husks and Sirens take 50% fire damage, but they are perma-stumbled before they do real harm. The same applies to Bloats; all trash gets perma-stumbled.

Sell and rebuy the Caulk n' Burn after you have consumed 125 ammo, because it is cheaper than refilling.

Share dosh. You spawn with your whole loadout, so you only need money for ammo and a medic pistol.

Control Hans. Hans seems to avoid ground fire and can be steered by it, even when he tries to drain.

Skills

The Firebug skill choices.

• Supplies: depends on the weapon. You want 100 fuel in the tank or you will reload while overwhelmed.
• Spicy (ground fire): ground fire does significantly more damage than afterburn or impact, 10 damage (5 for the Microwave Gun) every 0.25 s, doubled to 20 with the ground fire skill. Flamethrower and Caulk n' Burn deal the same ground fire. If you stop firing, almost all your damage stops; it is not the KF1 afterburn.
• Burn (zed shrapnel): 20% chance on a kill to deal 10 damage in a 2 m radius with linear falloff, with 500 knockdown, melee hit and stumble values. It can knock down a Scrake or an unraged Fleshpound, which can wreck a Sharpshooter's or Demolitionist's shot. With Napalm, ZEDs touching a burning ZED take 7 damage instantly and 35 over 12.5 s.
• Flame (Heat Wave): perma-stumbles all trash ZEDs, guaranteeing an escape route and letting you walk into their faces.
• Advanced training (Pyromaniac): the guide found it does not change the damage interval of spray weapons, so it does nothing to damage. Take Inferno instead.

Flamethrower vs Caulk n' Burn

	Caulk n' Burn	Flamethrower
Damage	10	21
Afterburn	34 over 1.7 s	57.12 over 1.7 s
Fuel	50	100
Ammo cost	20	83
Range with 1 hit	10.00 m	11.50 m
Range with 7 hits	3.50 m	4.50 m

Caulk n' Burn. You take no damage from it.

The flamethrower kills faster but is expensive.

The Caulk n' Burn range falls from 10 m (1 hit) through 8.8, 7.2, 6.35, 5.65 and 4.99 m to 3.5 m at 7 hits; the flamethrower goes from 11.5 m through 11.2, 11.0, 10.75 and 10.0 m to 7.0 and 4.5 m. Conclusion: the flamethrower is faster but costly, so you may do better giving dosh to teammates, starting with the medic.

Bottom line

You can get away with the Caulk n' Burn alone: sprint and tap fire is all there is to it, and the spare weight lets you pick up other weapons without compromising the build.