Sealant & Caulking Guns

About Sealant & Caulking Guns

Sealant and caulking guns are essential tools for applying controlled beads of adhesive, sealant, mastic, and filler materials in both professional trade work and DIY projects. Whether you're sealing bathroom fittings, filling gaps in decorative mouldings, weatherproofing external joints, or applying specialist adhesives, the right applicator gun ensures precise, consistent application with minimal waste. This comprehensive category encompasses everything from basic skeleton guns for occasional use through to professional-grade cordless applicators from leading brands including DeWalt, Makita, and Milwaukee.

The range includes manual caulking guns with various thrust ratios for different viscosity materials, battery-powered models for high-volume applications, and specialist foam guns for controlled expanding foam dispensing. Alongside the applicator tools themselves, you'll find an extensive selection of sealants and fillers tailored to specific applications—from silicone bathroom sealants and decorators' acrylic caulk to specialist roof and gutter sealants designed to withstand the UK's challenging weather conditions.

Completing the category are essential accessories including spare nozzles, sealant smoothing tools, cleaners and removers, and consumables that ensure professional-quality finishes. Whether you're a bathroom fitter, general builder, decorator, or homeowner tackling maintenance projects, having the correct combination of applicator gun and sealant material is crucial for achieving durable, weathertight seals that stand the test of time.

Jargon Buster

• Thrust Ratio: The mechanical advantage of a caulking gun, typically ranging from 6:1 to 26:1. Higher ratios provide more force for thicker, more viscous materials with less effort on the trigger. Professional tradespeople often prefer 12:1 or higher for consistent flow control.
• Skeleton Gun: A basic, lightweight manual caulking gun with an open frame design. The most economical option for occasional use, these guns lack the pressure release mechanism found on more advanced models.
• Sausage Gun: A specialist applicator designed for foil sausage-pack sealants rather than rigid cartridges. These reduce packaging waste and are popular on larger commercial sites where bulk sealant application is required.
• Anti-Drip Mechanism: A feature that automatically releases pressure from the cartridge when the trigger is released, preventing unwanted sealant ooze and reducing material waste—essential for professional finish quality.
• Modulus: The measure of a sealant's stiffness or flexibility once cured. Low-modulus sealants remain more flexible and are ideal for joints with significant movement, whilst high-modulus types are firmer and better for structural applications.
• Gungrade vs Non-Gungrade: Gungrade sealants are thicker, designed to be dispensed through applicator guns in controlled beads. Non-gungrade types are squeezable from tubes by hand and suited only for very small-scale applications.

Who Uses Sealant & Caulking Guns?

• Bathroom and Kitchen Fitters – applying silicone sealants around baths, showers, sinks, and worktops to create watertight seals
• Decorators and Painters – filling gaps in skirting boards, architraves, coving, and other joinery with acrylic caulk before painting
• General Builders and Maintenance Contractors – sealing window and door frames, filling expansion joints, and general gap-filling across construction projects
• Roofers and Guttering Specialists – applying weatherproof sealants to flashing, ridge tiles, gutter joints, and roof penetrations
• Glaziers and Window Fitters – sealing glazing units and weatherproofing external window frames
• HVAC and Plumbing Engineers – sealing pipe penetrations, ductwork joints, and creating airtight seals around service installations
• Shopfitters and Joiners – filling gaps in fitted joinery, cabinets, and architectural millwork
• DIY Enthusiasts and Homeowners – tackling home maintenance, bathroom upgrades, draught-proofing, and general repairs

How to Choose the Right Sealant & Caulking Guns

Application Frequency: For occasional DIY use, a basic skeleton gun or standard manual caulking gun with a 10:1 or 12:1 thrust ratio will suffice. Professional tradespeople working daily with sealants should consider premium manual guns with anti-drip mechanisms or invest in cordless models from Makita, DeWalt, or Milwaukee for consistent pressure, reduced hand fatigue, and significantly improved productivity on larger projects.

Sealant Viscosity: Different materials require different force levels. Low-viscosity silicones work well with basic guns, but thick mastics, adhesives, and winter-grade sealants demand higher thrust ratios (18:1 to 26:1) or powered applicators. Match your gun's capability to the materials you'll use most frequently.

Cartridge Type: Standard 310ml cartridges are most common, but check whether you need compatibility with foil sausage packs (requiring a sausage gun or conversion kit) or larger commercial cartridges. Some cordless models accept multiple sizes for greater versatility on site.

Powered vs Manual: Cordless caulking guns deliver consistent pressure, adjustable flow rates, and eliminate hand fatigue—invaluable for bathroom fitters or anyone applying numerous cartridges daily. They represent a significant investment but pay dividends in productivity and finish quality. Ensure compatibility with your existing battery platform (18V is standard across major brands).

Build Quality and Features: Professional-grade guns feature rotating barrels for precise angle control, quick-release cartridge mechanisms, built-in cartridge puncture tools, and robust steel construction. Anti-drip functionality is essential for clean work and reduced waste. Cheaper models may suffice for light use but won't withstand daily site work.

Specialist Applications: Expanding foam requires dedicated foam guns with screw-thread applicators for controlled dispensing and reusability. These are essential for window installation, cavity filling, and insulation work where precise foam placement matters.

Popular Accessories

• Replacement Nozzles – various bore sizes and angles for different bead profiles and access to awkward spaces
• Sealant Smoothers and Finishers – profiling tools and spatulas for achieving professional, concave joint finishes
• Sealant Removers and Cleaners – specialist solvents and scrapers for removing old sealant before reapplication
• Masking Tape – essential for achieving clean, straight sealant lines, particularly in decorative applications
• Gun Cleaning Brushes and Tools – maintaining your applicator gun, particularly important for foam guns to prevent blockages
• Extension Nozzles – reaching deep cavities, behind radiators, and other inaccessible areas
• Spare Plungers and Seals – replacement wear parts for manual caulking guns
• Cartridge Holders and Site Storage – organised transport and storage solutions for multiple sealant types

Safety Information

When working with sealants and application equipment, always ensure adequate ventilation, particularly with solvent-based products and expanding foams that release vapours during application and curing. Consult product safety data sheets for COSHH compliance on commercial sites, and note that some specialist sealants require specific PPE including gloves and eye protection.

Many sealants are skin irritants, so avoid direct contact and wash immediately if contact occurs. When using expanding foam, wear protective gloves as cured foam is extremely difficult to remove from skin. Ensure foam guns are properly cleaned after use according to manufacturer instructions to prevent blockages and maintain safe operation.

Cordless caulking guns generate significant pressure—never point the nozzle towards yourself or others, and ensure cartridges are correctly seated before operation. Release pressure fully before removing cartridges to prevent sudden sealant discharge. Store partially used cartridges with sealed nozzles to prevent material hardening and ensure applicator guns are depressurised when not in use.

Frequently Asked Questions

What's the difference between silicone sealant and acrylic caulk?

Silicone sealant remains permanently flexible, is waterproof, and ideal for areas with movement or constant water exposure like bathrooms and external joints. However, it cannot be painted over. Acrylic caulk (decorators' caulk) is paintable, making it perfect for filling gaps in interior joinery before decorating, but it's not suitable for wet areas or joints with significant movement as it can crack over time.

Do I need a cordless caulking gun or will a manual one do?

For occasional home maintenance and small projects, a quality manual gun is perfectly adequate and costs considerably less. However, if you're a professional tradesperson applying multiple cartridges daily—particularly bathroom fitters, decorators, or maintenance contractors—a cordless model from DeWalt, Makita, or Milwaukee will dramatically reduce hand fatigue, provide consistent bead quality, and increase productivity enough to justify the investment within weeks.

Can I use any caulking gun with expanding foam?

No—expanding foam requires a dedicated foam gun with a screw-thread valve mechanism. Standard caulking guns don't provide the control needed for foam application, and professional foam guns allow you to start and stop flow instantly, adjust output, and can be cleaned and reused multiple times with proper maintenance. They're essential for window fitting, cavity insulation, and any application requiring precise foam placement.

How do I prevent sealant continuing to ooze after I've released the trigger?

This is caused by residual pressure in the cartridge. Better-quality caulking guns feature an anti-drip or pressure-release mechanism that automatically relieves pressure when you release the trigger. On basic skeleton guns without this feature, you need to manually release the plunger rod pressure by twisting or pulling it back slightly after each application—tedious on larger jobs but essential for clean work and preventing waste.

What thrust ratio should I look for in a manual caulking gun?

For most general-purpose applications including standard silicones and acrylic caulks, a 12:1 thrust ratio provides a good balance of control and power. If you regularly work with thicker mastics, adhesives, or cold-weather sealants, consider 18:1 or higher. Lower ratios (6:1 to 10:1) are fine for occasional DIY use with free-flowing materials but will cause hand fatigue with professional workloads or viscous products.