How to use an air caulking gun
Updated: 23 October 2026
How to use an air caulking gun starts with that gun’s own maximum, not with the pressure sitting in the tank. A full receiver can be 8 bar or more. Clarke’s CAT82B manual says do not exceed 90 psi and recommends no more than 70 psi while running. Sealey’s AK41.V3 stops at 3 bar. This sequence comes from those manuals, from HSE guidance on compressed air, and from UK review themes on the Clarke in our [air caulking gun comparison](/hub/fillers-adhesives-and-sprays/air-caulking-gun). If you buy through our links, we may earn a commission at no extra cost to you.
How to use an air caulking gun starts with that gun’s own maximum, not with the pressure sitting in the tank. A full receiver can be 8 bar or more.
How to use an air caulking gun starts with that gun’s own maximum, not with the pressure sitting in the tank. A full receiver can be 8 bar or more. Clarke’s CAT82B manual says do not exceed 90 psi and recommends no more than 70 psi while running. Sealey’s AK41.V3 stops at 3 bar. This sequence comes from those manuals, from HSE guidance on compressed air, and from UK review themes on the Clarke in our air caulking gun comparison. If you buy through our links, we may earn a commission at no extra cost to you.
Our top picks
| Badge | Product | Flow control | Stated pressure | Pack | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  banapoy banapoy 600 ml pneumatic caulking gun | n/a | 0–123 psi | 600 ml sausage | 4.9 | about £65.44 | View offer |
| Best value |  Chicago Pneumatic Chicago Pneumatic CP9885 | Trigger metered | 6.3 bar (maker) | 2 in × 8.5 in | 7.2 | about £40.71 | View offer |
 Clarke Clarke air driven caulking gun | Full trigger | 4.8–10.3 bar | 215 × 50 mm | 8.6 | about £26.99 | View offer |
On this page
Set the regulator before the cartridge
Find the maximum in the manual for the gun in your hand. Clarke’s amazon line says 4.8–10.3 bar, and that top end is above the CAT82B manual, so use the manual: not above 70 psi while running, and not above 90 psi. A Sealey or SIP gun capped at 3 bar is a different ceiling. Trigger off while you connect the hose. Do not hang a quick-coupling on the Clarke, and drain water from the compressor. If the gun has no regulator of its own, fit one on the hose. UK reviews say the Clarke trigger is all-or-nothing until that regulator slows the air. Flow and receiver size are on the compressor for a caulking gun page.
Load so the air pushes sealant, not past it
Cut the nozzle at an angle and pierce the inner foil before the tube is in a live gun. Misshapen tubes will not seal: air escapes and nothing moves. The end-cap washer has to sit flat, and a cross-threaded cap will not hold pressure. Seat the plunger so air cannot slip past it. On the CP9885, reviewers say the cartridge has to be started before loading, or air enters the tube. Do not drill the barrel to make a dented tube fit. Point the nozzle at scrap for the first squeeze. Which pack fits which gun is on the pneumatic caulking gun buying guide.
Walk a bead you can stop
Hold the gun so the nozzle fills the joint from the back, and move at a pace the bead can keep up with. Air does not give you a slower hand. It gives you more force. If the bead races ahead, the pressure is high or the nozzle is too large.
When it hisses, blasts, or will not stop
A hiss with no sealant usually means air is escaping at the cartridge, the washer, or the end cap, not that the compressor is too weak. Check that the tube is round, the foil was pierced, and the cap is seated on a clean thread. Clarke reviews mention end caps that strip after repeated tubes. Replace the cap rather than leaning on the trigger. If you would rather squeeze a 25:1 gun, that decision is on the pneumatic vs manual caulking gun page.
Disconnect, eyes, and skin
Trigger off, then disconnect, before you open the barrel, change a tube, or put the gun away. Store it unpressurised, and drain water from the compressor. HSE’s HSG39 is blunt: compressed air can enter the body through the skin, a burst hose can whip, and you do not blow dust off skin or clothes with the line. If air has punctured the skin, or you feel bubbling under the skin, go to A&E or call 999. Sealant in the eye needs medical help too. Wheeze or rash after polyurethane or isocyanate products is a problem for the cartridge, not a reason to turn the gun up.
Common questions
Where do I set the regulator?
Below the maximum in that gun’s manual, not at whatever the tank gauge shows. For the Clarke CAT82B the manual recommends no more than 70 psi while running and says do not exceed 90 psi. A Sealey AK41.V3 is a 3 bar gun. Start low enough that a scrap bead creeps, then raise it until the sealant moves steadily. The amazon marketing line of 4.8–10.3 bar on the Clarke is not permission to use 10.3 bar.
Do I pierce the cartridge before it goes in the gun?
Yes. Cut the nozzle and pierce the foil while the hose is off and the barrel is open. If you pierce after the tube is pressurised, you are working on a live gun. Seat the plunger so air pushes sealant rather than blowing past it. A dented tube will not hold that seal.
Why does air leak and nothing come out?
The usual causes in UK Clarke reviews are a damaged cartridge, a washer that is not seated, or an end cap that is cross-threaded or stripped. Excess pressure can also oval a 310 ml tube so air slips past the plunger, which is the failure Bostik describes for pressured-air guns. Disconnect, inspect the tube and the cap, and lower the regulator before you try again.
Why does the whole tube empty at once?
The trigger is wide open and the regulator is too high. Clarke reviews call that all-or-nothing flow. CP9885 reviews describe the same surprise on a high setting. Prove the speed on scrap. If there is no regulator on the gun, fit one on the hose. Do not keep the tank at 8 bar and hope a light touch on the trigger will save the joint.
When do I disconnect the hose?
Before you open the barrel, change the cartridge, clear a jam, or store the gun. Connect with the trigger off. Clarke’s manual does not want a quick-coupling left on the tool. A live barrel is how end-cap threads get forced and how sealant leaves in a hurry when you did not mean to fire.
Can I blow dust off my hands with the line?
No. HSE guidance on compressed air says not to clean skin or clothing with it. Air can enter the body through a small break in the skin, and the injury is not always obvious at once. Use a brush or a cloth. If air has already punctured the skin, that is urgent care, not a rinse-and-see.
Related pages
Sources
Public UK sources used for this comparison. amazon.co.uk prices, stars and review counts were taken from the listings on 19 October 2026.
- HSE HSG39, compressed air safety (retrieved 19 October 2026)
- Pressure Systems Safety Regulations 2000 (retrieved 19 October 2026)
- Control of Noise at Work Regulations 2005, regulation 4 (retrieved 19 October 2026)
- HSE, isocyanates in construction (retrieved 19 October 2026)
- Clarke CAT82B product page (retrieved 19 October 2026)
- Clarke CAT82B manual (retrieved 19 October 2026)
- Chicago Pneumatic CP9885 (retrieved 19 October 2026)
- COX AirFlow 3 310 ml (retrieved 19 October 2026)