How do I use spray adhesive without it going everywhere?

Spray adhesive is the right answer for large, thin, flexible sheet materials where a brushed or rolled adhesive would wrinkle or show through: fabric, paper, photographs, foam, insulation facings, felt. Everything difficult about it comes from the fact that it arrives as an airborne mist, so a proportion of it lands somewhere you did not intend.

Safety

What you'll need

• spray adhesive of the right grade
• a cardboard box or sheeting to catch overspray
• a mask rated for organic vapour, and ventilation
• masking tape and paper
• nitrile gloves
• a roller or a clean block for pressing down

Step by step

1. Buy the right grade for the job.Repositionable grades stay tacky and let you lift and re-place a sheet many times — right for templates, patterns and temporary mounting. Permanent grades bond hard. Fabric, foam and photo-safe grades exist for a reason: general-purpose spray can stain photographs and dissolve polystyrene foam.
2. Set up a booth before you open the can.A large cardboard box on its side, or sheeting taped up in a corner. Overspray travels well beyond the piece you are spraying, and it lands on the floor, the tools and the workpiece you were about to use next.
3. Mask anything that will not be sprayed.Especially the edges of a workpiece where the adhesive should stop. It is far easier to tape a line than to remove a tacky halo afterwards.
4. Shake the can hard for a full minute.Longer than feels necessary. Under-shaken spray adhesive comes out in a spitting, uneven pattern with blobs, and the blobs show as lumps through thin material.
5. Hold the can about twenty-five centimetres away and keep it moving.Even passes with about half overlap, starting and finishing off the edge of the workpiece so there is no heavy patch where you began. Two light coats beat one heavy one.
6. Decide on one face or two.Spraying one face gives a repositionable, lower-strength bond even with a permanent grade. Spraying both and letting them go tacky gives a much stronger, contact-style bond you cannot reposition. This choice matters more than the product.
7. Let it go tacky before joining.Usually thirty seconds to a couple of minutes. Joining while it is wet gives a weak bond and squeezes adhesive out at the edges.
8. Press or roll the whole area from the centre outwards.As with contact adhesive, pressure makes the bond and it also drives out trapped air. Work from the middle to each edge so nothing is sealed in.
9. Clear the nozzle before you put the can away.Invert the can and spray for two seconds until clear gas comes out. A blocked nozzle is the reason most part-used cans are thrown away, and it takes five seconds to prevent.

Tips

• Overspray is invisible on the floor and picks up dust and grit for weeks. Sheet the floor, or work outside on a still day.
• Cold cans spray badly. Keep the can at room temperature and warm it in your hands for a minute if it has been in a shed.
• For mounting artwork or photographs, use a photo-safe or acid-free grade. Ordinary spray adhesive yellows and can stain a print permanently over a few years.
• General-purpose solvent-based spray dissolves expanded polystyrene on contact. If you are gluing insulation or model foam, buy the grade that says foam-safe.
• Isopropyl alcohol or a citrus-based cleaner takes fresh overspray off hard surfaces. Test it somewhere hidden first, because both attack some finishes.

Common mistakes

• Spraying indoors with the door shut — The mist fills the room, settles on everything, and it is both flammable and unpleasant to breathe. This is the mistake that ruins a room rather than a workpiece.
• One heavy coat — It stays wet underneath, soaks through thin material and shows as blotches. Two light passes give an even film and dry properly.
• Joining while it is still wet — The bond is weak and the edges ooze. Wait for tack.
• Using a general-purpose grade on foam or photographs — The solvent dissolves polystyrene and the adhesive stains prints. Both are irreversible.

Questions people ask