“I told you, I am welding this door!” —Lt. Masterson
The Welder is a tool used by players to basically "lock" any functioning door in the game. Once the player welds a door, specimens would often take a different path to avoid the welded door while a few specimens will still try to break it open. Players can also un-weld doors by using the Alt-fire button to open up a door. This process is much faster compared to welding and uses less battery power. The welder also needs to recharge after its battery runs out. A player can continuously hold the primary fire button but once the battery runs out it will weld doors very slowly. Team-mates may assist in welding doors by welding onto the same door simultaneously, this will make the door weld a lot faster and will not demand so much use of the battery. To recharge the battery, simply do not weld or un-weld any doors for a moment, it will recharge in just a few seconds and will recharge even if the player is holding another weapon.
Support specialists get a very large boost to welding intensity per unit spent, allowing for faster welds with less battery power used. Allowing a single Support to weld any door to 100% integrity in mere seconds. The Berserker perk also receives increased welding speed, approximately 25% faster because the welder is considered a melee weapon. However it does not increase the amount of battery power.
A door's health is measured by integrity which is shown as a percentage. Its integrity will decrease with every hit, and the rate at which it decreases depends on the strength of the attacking specimens. When the integrity of a welded door is reduced to 0 by attacking specimens, the door is destroyed and cannot be welded until it respawns at the end of the wave. However, this can be avoided by unwelding the door when it is near-destruction, preventing specimens from destroying the door, and allowing it to be welded again within the same wave. A welded door can also be quickly destroyed by grenades. Different doors have different health; larger doors generally have more maximum hit points, but take more time to weld.
The Welder may be seen lying on the ground having been dropped by a player killed while holding it; attempting to pick it up will give you the message "You already have this weapon', since every player spawns with it and cannot discard it.
In solo mode, welding a door that has been recently destroyed will be slower than a door that was never destroyed. How much slower varies from door to door and map to map.
- Taking over the door generally requires communication, welding player using voice command "Help!" or "Weld the doors." should be enough of a clue for some other player to take the duty for a while. When door is about to give in and break from the specimen attacks "Look Out!" voice command can help team to pay attention and clear the horde in a timely manner before getting flanked.
- The door health display on the welder stays active as long as you are near the door, not necessarily facing it, allowing you to keep an eye on the door without having your back to the battle.
- If two nearby doors are welded with different integrity, then specimens will generally attack the weaker integrity door first. If most doors leading to the squad are near equally welded without giving way for any spawn stream, they will attack all of them eventually. Welding all the doors leading to the squad will cause specimen to attack them all at once, regardless of the integrity percentage. Welding all doors not only waste everyone's time, it also cause team to get eventually overwhelmed by the massive toppled aggro hammering the doors all at once.
- It should be noted that the Welder is always fully discharged when a player spawns, and as such can make it much more problematic to weld a door in the first few seconds of a game upon spawning in. Welding a door outright is not crucial as early as first wave where only low threats appear. Upon respawning you will still have enough time to quick tap a close enough door before heading to the trader.
- A squad should have a member committed to welding a door often if they want to keep it closed. This often falls on to the Support Specialist but other teammates might need to take over the duty for Support Specialist to clear the excess trash and open breathing space for team at the front lines. The Berserkers have an odd bonus to the tick rate of Welder as it considered a melee attack of sorts. When Support Specialist asks for help, a Berserker can easily take over for a while to weld or unweld quicker than Support Specialist and can to take the brunt of aggro while Support is safe to provide cover fire.
- From a small opening such as a window nearby to a door post, a Firebug can scorch anything behind the welded door to keep the door secure. It's advised not to kill any small specimen outright attacking the door as something bigger and more troubling can take its place at early in the wave. Peeking frames installed on the doors and top windows can be used to negate the attacks of some medium specimen come knocking on the door by the help of a Demolition with grenade launchers or Field medic besides Firebug. Such doors can be secured at well known hold spots in the Biotics Lab, Hillbilly Horror and Evil Santa's Lair.
- In case a narrow door or any door nearby the hold position can be cleared easily by splash damage through an opening, it's best awaiting a huge aggro of multiple specimen on it first before attempting it. A small zed attacking a narrow door will prevent bigger specimen to tear it down quickly and its damage can be out repaired easily. Doors that are welded outside of team's view or too wide, must be cleared immediately or welded for a while to prevent any bad surprises, depending on wave's progress of specimen left.
- Spamming explosives at open crosspaths to score huge chunk of kills cause specimen to respawn all over the place to take the least resistance path. When this happens they will take their time and start attacking nearby doors to flank the team. Listen for any noise of scratching to keep welding or clear the doors along a late wave. Also clearing a huge chunk of specimen toppled behind a welded door will cause front to take the brunt of increased spawn rates by tightened delays for spawning new specimen.
- You can actually kill a specimen with a welder by letting it come close to the door, point the welder at the door, start welding and then rapidly flick your view to specimen. That will cause specimen to incur some minor damage with each tick but loop will stop after a brief moment so you have to repeat it until it's dead or got away from that position. Some spots in official maps are infamous with their object placement near doors which would allow a specimen to get stuck behind doors by messing their waypoint navigation. This can be fun if you are the last man standing, all teammates are dead, and the last specimen is a clot. This exploit happened after Summer Sideshow of 2013 and haven't fixed since, as it might be intentionally left in there.
- Be careful while welding one door with teammates. If you turn to another player next to you while welding a door you can harm him. It does not do that much damage, but it also costs kevlar. Some players use this as a Griefing device to kill others or a way of punishing players who are fixated on welding unnecessary doors.
|Equipment by perk|
|Weapon damage table|