TriggerEach squeeze pushes the rod a short way forward.
HandleThe fixed grip that the trigger closes against.
CartridgeThe disposable tube that holds the caulk.
NozzleIts tip is cut off to open the cartridge.
FrameReceives the cartridge and holds it in line with the rod.
Piston rodSlides forward through the handle as the trigger is squeezed.
Rod handleThe bent end you pull to draw the rod back.
PistonPresses on the movable base of the cartridge.
Release triggerPress it to free the rod so it can slide back.
Frame, rod and handle 1
Seal punchA thin rod for piercing the seal in a new cartridge.
Inside the handle 4
Spout cutterA hole with a blade that snips off the nozzle tip.
Drive gripTilts to bite the rod and carry it forward.
SpringsTwo coil springs on the rod reset the grip and the release.
Pivot pinThe trigger swings on this pin.
The cartridge 1
Inner sealKeeps the caulk shut in until it is pierced.
How this list was compiled: Part names and every detail line were checked, for facts only and with nothing copied, against pages read on 2026-09-20, and the part names again on 2026-09-30 in the same pages. An encyclopedia: https://en.wikipedia.org/wiki/Caulk (caulk is sold in disposable cartridges, rigid tubes of cardboard or plastic: applicator tip at one end, movable plunger at the other; the gun has a trigger connected to a rod that pushes the plunger; some guns have a ratchet; the push rod can also be driven by a motor or by compressed air). Two home-improvement how-to guides: https://www.bobvila.com/articles/how-to-use-a-caulk-gun/ (a blade in the handle as a built-in cutter, a poker for the internal seal, the release trigger on the handle, the rod and its hook, the nozzle and the flat base of the tube) and https://www.familyhandyman.com/project/how-to-use-a-caulk-gun/ (the smooth rod gun, spout cutter, seal puncher for the inner seal, the metal trigger on the back, the L-shaped rod and the base plate of the rod). Six patents, read at Google Patents: https://patents.google.com/patent/US4081112A/en (handle, trigger on a rivet, plunger shaft with a thrust disk, a drive grip and a release grip that hold the shaft when tilted, two compression springs), https://patents.google.com/patent/US5887765A/en (piston rod, drive grip or drive dog, spring, pivot pin, tube housing, notches along the rod as the ratchet alternative), https://patents.google.com/patent/US4461407A/en (barrel, ratchet rod with teeth and pawl, smooth piston rod with drive grip, piston, the bent end of the rod as a handle, coil spring, pivot pin), https://patents.google.com/patent/US5370282A/en (piston rod, piston, two clamping levers, two compression springs, dispensing nozzle), https://patents.google.com/patent/US9302290B2/en (piston rod and piston, advance plate and hold plate, a pair of compression springs, pivot pin, seal punch, tip cutter, caulk tube with canister and dispensing tip) and https://patents.google.com/patent/US6056156A/en (frame, plunger shaft, return spring, built-in spout cutter between handle and trigger, spout and tip of the cartridge). A caulking gun maker's catalog: https://dripless.com/application/files/7616/9282/0305/Catalog_01_2022.pdf (cradle frame and skeleton frame, ratchet rod, hex rod and round rod, cutter and poker, drive dog). Three owner's manuals for powered caulking guns, read in full text at the Internet Archive and used only for names the hand gun shares: https://archive.org/details/manualsonline-id-1131c7a9-346f-4763-b782-86358973a5fd (carriage frame, plunger, plunger rod, plunger rod handle, plunger rod release trigger, puncture tool), https://archive.org/details/manualsonline-id-653c26c5-4d4e-483f-8289-346474364c89 (piston, rod, rod handle, carriage, nozzle of the tube) and https://archive.org/details/manualsonline-id-f87b4afa-708d-4833-94e4-061bd845cef6 (plunger, cartridge holder, trigger). A label is a name that at least two of these sources use for the part. Every other sourced name is an accepted typed answer. Names found in one source only, or in none, are listed in leftOut and are not asked. Licence: own work
The drawing: Drawn for this site on 2026-09-30 from plain geometry. Own original schematic drawing of a composite teaching tool; nothing traced or copied, and no patent figure or maker's picture was looked at while drawing. Licence: own work
How it works
The parts of a caulking gun are few on the outside: frame, trigger, handle and a long rod. The work happens inside the handle, so a second drawing cuts it open to show the drive grip, the release trigger and their springs.
Read the full guide
How the trigger moves the rod
Squeezing the trigger swings it on its pivot pin, and its upper end pushes the drive grip. The drive grip is a plate with the smooth rod through a hole in it. Pushed, it tilts, bites the rod and carries it forward. The piston on the front of the rod presses on the base of the cartridge, and caulk leaves through the nozzle. Let go, and a spring slides the drive grip back.
Why the rod stays put until you release it
The release trigger is a second plate behind the handle. Its own spring keeps it tilted, so the rod cannot slide back. Press it and the rod runs free. Then the rod handle draws the piston back.
Start here: 9 main parts covers the outside of the gun before the quiz moves to the plates and springs inside the handle.
Typed answers take the names other sources use: plunger for piston, poker for seal punch, cradle for frame, tube for cartridge.
Questions and answers
What are the parts of a caulking gun called?
The frame holds the cartridge. The piston rod runs through the handle, with a piston at the front and a rod handle at the back. The trigger drives it and the release trigger frees it. Many guns add a seal punch and a spout cutter.
What is the thin metal rod on a caulking gun for?
It is the seal punch, also called a poker: a thin rod kept under the frame for piercing the inner seal of a new cartridge. On a gun without one, a nail or a wire does that job.
What is the hole in the handle of a caulking gun for?
It is the spout cutter. The tip of the nozzle goes into the hole and a small blade snips it off. Not every gun has one.
What is the difference between a ratchet rod and a smooth rod caulking gun?
A ratchet rod has teeth along one side, and the drive catches them to push the rod forward. A smooth rod has no teeth: a tilted plate, the drive grip, bites it instead. This drawing shows the smooth rod kind.