The mortar gun is a compact pressing tool for the metered placement of mortars and injection compounds into boreholes, joints, and voids. In the context of concrete demolition, interior demolition, and rock cutting/processing, it bridges the gap— as a precise handheld device—between heavy demolition tools and professional restoration, sealing, or anchoring. In workflows with tools from Darda GmbH such as hydraulic demolition shear or hydraulic splitter, the mortar gun enables clean follow-up operations—such as setting anchors, filling boreholes, or repairing edges—in a controlled, material-appropriate, and low-emission manner.
Definition: What is a mortar gun
A mortar gun (also cartridge gun, mortar pistol, or injection gun) is a manual or powered press device that dispenses pasty to slightly flowable construction materials—such as injection mortar, repair mortar, grout mortar, or sealants—in a metered way from cartridges, foil packs, or a fill cylinder. Characteristic features include a force-multiplying mechanism, a piston, a receptacle for the material pack, and attachable nozzles or mixing tubes. The goal is a reproducible, void-free fill installed while withdrawing—particularly in boreholes for anchors or when closing cracks and joints.
Design and operating principle of the mortar gun
A mortar gun consists of a housing, feed rod with piston, drive (manual lever, battery, or pneumatics), container holder (cartridge, foil pack, fill cylinder), and interchangeable nozzles. Lever stroke or powered drive generates thrust that conveys the mortar through the nozzle. For 2C systems, a mixing nozzle ensures homogeneous blending of the components. Decisive factors are the material’s viscosity, nozzle geometry, and the force multiplication ratio: together they determine delivery rate, application quality, and the maximum permissible aggregate size.
Fields of application in deconstruction, refurbishment, and rock works
The mortar gun is used wherever controlled placement of mortar material is required—often as a downstream or preparatory step to hydraulic demolition and cutting. Typical links to tools and applications from Darda GmbH include:
- Concrete demolition and specialized deconstruction: After separating or breaking with hydraulic demolition shear, fracture edges can be reprofiled with repair mortar, voids filled, or anchors set for temporary shoring.
- Interior demolition and cutting: During interior strip-out, injection mortar is placed via mortar gun for dowels and rebar connections to secure components before using combination shears, Multi Cutters, or steel shear.
- Rock demolition and tunnel construction: Anchors for stabilization can be set in boreholes or local sealing of water inflows can be achieved; after work with hydraulic splitter the bores can be selectively closed.
- Natural stone extraction: Jointing and placement of natural stone benefit from metered application, especially in narrow joints or for localized backfilling.
- Special applications: In vibration-sensitive areas, the mortar gun enables low-vibration filling, fixing, and sealing—matched to constraints such as dust and noise limits.
Variants and material compatibility
Mortar guns differ by container type, drive, and mixing system. The right choice depends on material, volume needs, and installation conditions.
Cartridges, foil packs, or fill cylinder
Cartridges are clean and quick to change; foil packs reduce residual amounts and suit larger volumes; fill cylinders are charged with loose mortar when processing mineral repair or grout mortars with defined aggregate size.
1C and 2C
1C materials (e.g., repair and joint mortars) are pressed directly. 2C injection systems (e.g., chemical anchor mortars) require twin cartridges and mixing tubes; pot life and temperature windows must be strictly observed.
Aggregate size, viscosity, and nozzle
Nozzle-fed guns are ideal for fine-grained systems (typically 0–1 mm). The higher the viscosity, the greater the required thrust and nozzle cross-section. Angle or extension nozzles facilitate filling from the hole base while withdrawing.
Planning and selection: criteria for the right mortar gun
- Material: Injection mortar, repair mortar, grout mortar, or sealant—including approvals (e.g., European Technical Assessments) and manufacturer guidance.
- Thrust force and ratio: Sufficient pressure reserve for cold temperatures and viscous products.
- Container format: Compatibility with cartridges or foil packs; fill cylinder for loose materials.
- Ergonomics: Weight, balance, trigger comfort, and drip stop for clean work overhead or in tight shafts.
- Accessories: Mixing tubes, extensions, angle and needle nozzles, anti-drip/retraction locks.
- Cleaning and maintenance: Easily detachable parts, solvent-resistant seals, robust piston faces.
Workflow: step by step to a void-free result
- Prepare the substrate: Blow out/brush the borehole, clean cracks and joints; create a sound, dust-free, slightly pre-wettable substrate.
- Select the material: Choose mortar to match strength, exposure, and member geometry; observe the pot life.
- Set up the gun: Check the piston, insert the cartridge or pack, fit the mixing or application nozzle, trim the nozzle if necessary.
- Test feed: Pump until homogeneous material exits the mixing nozzle; discard the first centimeters.
- Placement: Fill void-free from the deepest point while withdrawing; maintain steady feed.
- Finishing: Install fixtures, remove excess, smooth edges; observe curing times.
- Documentation: Record batches, temperatures, times, and visual inspection; for anchors, verify pull-out values as specified.
Quality, safety, and environment
Personal protective equipment (gloves, safety glasses, and respiratory protection if required) is advisable even for mineral systems. Relieve pressure before changing nozzles. Process chemical products only in well-ventilated areas; observe safety data sheets and the manufacturer’s application guidelines. Dispose of extrusion residues properly; avoid introducing fresh mortar into waterways.
Typical errors and how to avoid them
- Insufficient substrate cleaning—leads to poor adhesion.
- Wrong nozzle or inadequate thrust—causes voids.
- Exceeded pot life—impairs strength and bond.
- Not filled while withdrawing—entrapped air and incomplete wetting.
- Ignoring temperature limits—deviating reaction times and viscosities.
Interfaces with tools and application areas of Darda GmbH
In concrete demolition and specialized deconstruction, the mortar gun often follows mechanical separation steps: After opening components with hydraulic demolition shear, Multi Cutters, or combination shears, anchors are set, edges reprofiled, or boreholes filled. In rock demolition and tunnel construction, it complements controlled splitting with hydraulic splitter through targeted filling or sealing. In interior demolition and cutting, it facilitates secure fastening of temporary hangers and installations before steel shears or tank cutters are used. The mortar gun is therefore not a replacement, but a precise complement to hydraulically powered tools and power units—ideal for downstream quality and safeguarding tasks.
Technical parameters and designations
- Thrust force/force multiplication: Measure of the ability to convey viscous materials through narrow nozzles.
- Delivery rate: Output per time; dependent on material, nozzle, and operation.
- Pot life/curing time: Time window for processing and loadability.
- Aggregate size/viscosity: Determines nozzle selection and gun type.
- Sag resistance/shrinkage: Relevant for overhead work and visible surfaces.
Normative and organizational aspects
For anchor and fastening work, the respective technical assessments and approvals of the chosen injection system are decisive. For concrete repair, applicable guidelines and product-specific application instructions apply. Internal site approvals, occupational safety, and environmental protection requirements must be strictly observed; specific requirements may vary by project.
Maintenance, cleaning, and storage
After finishing work, relieve the piston, remove the container, and clean or dispose of the nozzle. Flush the fill cylinder with a suitable cleaner; maintain seals and replace them when worn. Store dry, protected from dust, and frost-free. Regular visual inspection increases operational safety and prevents failures in use.
Distinction: mortar gun, injection pump, and cartridge gun
The mortar gun covers small to medium material quantities—mobile, quiet, and controlled. Injection pumps are suitable for large volumes or continuous injections. Simple cartridge guns without high multiplication are intended for low-viscosity products and short applications. The choice depends on material, volume, accessibility, and quality requirements.
Practice examples from the field
- After demolition with hydraulic demolition shear: Edge repair and void filling on beam heads; safe, targeted application of repair mortar.
- Before cutting operations: Setting temporary fixings using injection mortar for secure load transfer prior to using combination shears, steel shear, or tank cutter.
- Boreholes after hydraulic splitter: Closure and sealing to prevent water pathways or for surface preparation.
- Tunnel and rock environments: Local sealing and anchor installation in confined areas where low noise and dust are required.