A contact adhesive spray gun for foam uses, as a guide, around 100 to 200 l/min of air while spraying, at a pressure of 2 to 4 bar at the gun. It is the hungriest tool in an upholstery or trimming workshop, and it blows continuously during gluing. A single gluing station runs comfortably on an S 55 (0.6 m³/min at 8 bar); two stations with several staple guns call for a K 75 (1.1 m³/min).
The other tools of the trade are presented on our page compressor for upholstery and trimming.
What does an upholsterer use the adhesive spray gun for?
The spray gun applies contact adhesive to foam, wadding, board or wood. The upholsterer sprays both faces, waits for the adhesive to become tacky, then joins them. It is used to bond foam onto a seat frame, to build up several layers of foam of different densities, to fix wadding before stretching the fabric or, in automotive and marine trimming, to bond a covering onto a door card or a headlining.
There are two families of equipment:
- The cup gun, with a small adhesive container on the gun. Handy for small quantities and for changing adhesive.
- The gun connected to a pot or a pressure tank. Compressed air pushes the adhesive to the gun through a hose, and a second air supply is used to atomise it. This is the set-up used by workshops that glue a lot, in seat or mattress manufacturing.
What pressure to spray adhesive onto foam?
Contact adhesive is not sprayed like paint. It has to reach the foam as droplets or strands, not as a fine mist. As a guide:
| Setting | Order of magnitude | What happens if it is too high |
|---|---|---|
| Air pressure at the gun | 2 to 4 bar | Adhesive mist, wasted product, deposits all over the workshop |
| Pressure of the adhesive pot or tank | often 1 to 2 bar | Too much adhesive, runs, soaked foam |
| Network pressure | 8 bar | Nothing: the pressure is reduced at the station |
These figures vary with the adhesive, its viscosity and the gun. Follow the adhesive manufacturer's data sheet and the gun's manual. In every case, never connect the gun or the pot directly to the network's 8 bar: fit a regulator with a pressure gauge on each supply.
Too low a pressure has the opposite effect: the adhesive comes out in thick strands, spreads badly, and the bond lets go at the corners. The right setting is found by testing on a foam offcut.
How much air does an adhesive spray gun use?
While spraying, the gun uses around 100 to 200 l/min depending on the nozzle and the pressure. Our configurator uses 150 l/min. The difference from a staple gun is the way it is used: the upholsterer sprays a large surface in a single sweeping movement. The gun therefore blows continuously for several minutes. It is counted at 100%, whereas a staple gun, which fires in bursts, is counted at 50%.
The pressure tank, for its part, uses little air: it simply keeps the adhesive under pressure as it empties.
The calculation for a seat manufacturing workshop
Take a workshop with two gluing stations, four staple guns and one blow gun. Figures given as a guide, to be replaced with those in your manuals.
Step 1, the adhesive spray guns. 2 × 150 l/min, counted at 100%: 300 l/min.
Step 2, the staple guns. 4 × 80 l/min, counted at 50%: 160 l/min.
Step 3, the blow gun. 150 l/min, counted at 50%: 75 l/min.
Step 4, the total. 300 + 160 + 75 = 535 l/min.
Step 5, the safety margin. 535 × 1.25 = about 670 l/min.
Step 6, expansion. 670 × 1.2 = about 800 l/min, or 0.8 m³/min.
The K 75 delivers 1.1 m³/min at 8 bar with a 420 L air receiver, a refrigerated dryer and built-in filtration. It covers this need with some in reserve. With a single gluing station and two staple guns, the need falls to around 460 l/min and the S 55, 0.6 m³/min at 8 bar, is enough. For a mattress manufacturing line with several gluing stations, the K 110 goes up to 1.7 m³/min. The recommended air receiver volume can be checked with our air receiver size calculator.
Why must the air be dry at the adhesive spray gun?
The water in compressed air ends up coming out at the gun. In a contact adhesive, it disrupts curing: the film stays soft, the bond lets go a few days later, and with a solvent-based adhesive it can turn the film white. On a light-coloured fabric or foam, the sprayed drop leaves a ring. Oil carried over leaves a grey stain that cannot be put right.
Our compressors are lubricated: it is the filtration at the outlet that holds back the oil. For a gluing station, plan for a refrigerated dryer, then fine filters as close as possible to the gun. Our article dry, filtered air: no oil stains on the fabric explains the treatment chain in detail.
Precautions specific to gluing
- Solvent vapours. Solvent-based contact adhesives give off flammable vapours. Spray in a ventilated area, with extraction if possible, and never place the compressor in that area: it would draw in the vapours and heat them. Install it in a separate room. Depending on the quantities, your adhesive supplier and your health and safety adviser will tell you whether an ATEX (explosive atmosphere) risk assessment is required.
- Cleaning the gun. A clogged nozzle forces you to raise the pressure to get the same spray pattern, and air consumption goes up. Clean the gun at the end of the day with the solvent specified by the adhesive manufacturer.
- Venting the pot. Before opening a pressurised adhesive tank, shut off the air and vent it.
- Hoses. An adhesive hose running across the floor gets crushed by trolleys. Route it overhead, like the air.
- Pressure drop. A gluing station at the end of a long, small-bore hose can lose more than one bar. Our pressure drop calculator helps you choose the diameter.
To size your installation, enter your spray guns and staple guns in the configurator, then send us the data sheets for your adhesive and your guns with a quote request.
For your trade: Compressor for upholstery, auto trimming and soft furnishing workshops.