Which glue works on foam?
Which glue works on foam?
A foam-safe water-based adhesive or low-temperature hot melt — solvent adhesives dissolve polystyrene on contact.
Expanded and extruded polystyrene are dissolved by many common solvents — acetone, toluene, xylene and the carriers in most solvent contact adhesives — so the adhesive eats a groove in the foam and the joint collapses. Polyurethane and polyethylene foams are far more tolerant, which is why upholstery work can use products that would ruin a model. Because manufacturers change formulations, the reliable procedure is to test on an offcut rather than trust a label, and "foam safe" on a can means the maker has done that test for you. The other quiet problem is cure: closed-cell foam is impermeable, so a water-based adhesive between two large sheets can stay wet for days.
The options, ranked
| Option | Good at | Bad at |
|---|---|---|
| Foam-safe spray adhesive | Covers large areas evenly with no solvent attack, and the standard for upholstery foam and craft polystyrene. | Overspray travels, and the bond is modest until it has fully cured. |
| PVA or white craft glue | Cheap, safe on every foam, and strong enough for craft work. | Very slow to dry between two closed-cell surfaces, because the water has nowhere to go. |
| Low-temperature hot melt | Instant grab and no solvent, which is what makes it usable on thin polystyrene. | A standard-temperature glue gun melts a crater straight through the foam. |
| Polyurethane adhesive | Strong and gap-filling on polyurethane and polyethylene foams. | Foams as it cures, so it pushes parts apart unless they are weighted. |
| Contact cement | Excellent on polyurethane upholstery foam, with instant grab over a large area. | Solvent grades destroy expanded polystyrene, and the fumes need real ventilation. |
Technique that changes the outcome
- Test any unfamiliar adhesive on an offcut and watch for five minutes, not five seconds
- Apply in thin lines or a stipple rather than a flood, so water or solvent can escape
- Weight the joint lightly and evenly; foam crushes under a clamp
- For polystyrene, keep a low-temperature glue gun rather than a standard one
What goes wrong
- Solvent-based contact adhesive or superglue accelerator on polystyrene
- Standard hot melt on thin foam sheet
- Assuming an adhesive that worked on upholstery foam is safe on packing foam
Compiled practical guidance rather than a published standard. Product formulations vary by brand and market, so read the label — and where the work is structural, electrical or gas, the regulations that apply where you are govern rather than anything here.
Other glue and adhesive questions
| For | Use |
|---|---|
| Plastic | It depends entirely on which plastic — identify it first, because solvent cement is unbeatable on some and useless on others. |
| Polypropylene and polyethylene | Ordinary adhesives cannot wet these plastics at all. Use a polyolefin primer with cyanoacrylate, an MMA structural adhesive, or weld the plastic. |
| Wood | PVA wood glue for anything indoors; a water-resistant grade (Type I / D4) or polyurethane for anything that gets wet. |
| Metal | Two-part epoxy for anything structural, cyanoacrylate for small dry parts, and MMA where the surface cannot be properly prepared. |
| Ceramic and pottery | Two-part epoxy for anything that will be handled or loaded, cyanoacrylate for a clean break on a display piece — and neither is dishwasher-proof. |
| Shoes | A flexible shoe repair adhesive — polyurethane or a neoprene contact cement — never superglue, which cracks within a day of walking. |
| Fabric | A washable fabric adhesive or a fusible bonding web — and never superglue, which reacts with cotton violently enough to burn. |
| Glass | UV-cure glass adhesive for an invisible joint, clear epoxy where it must hold load, and neutral-cure silicone where it must stay flexible or wet. |
| PVC pipe | PVC solvent cement with its matching primer — and PVC, CPVC and ABS cements are not interchangeable. |
| Tiles | A cement-based thin-set in almost every case; ready-mixed tub adhesive only on small dry walls, never on floors or in showers. |
| Phone screens | A pre-cut adhesive gasket, or a flexible B-7000-type adhesive around the frame — superglue destroys screens and is the classic mistake. |
| Rubber | Contact cement for large flexible areas and rubber-toughened cyanoacrylate for small ones — but silicone and EPDM need a primer or they will not bond at all. |
| Outdoor and waterproof joints | Polyurethane or epoxy for rigid joints, MS polymer where the joint has to move — and check the water-resistance class rather than the word "waterproof". |
| Acrylic (Perspex, Plexiglas) | A solvent cement run into the joint by capillary action — not a tube adhesive, which will always look like a repair. |
| Concrete | Epoxy or a construction adhesive for bonding to it, and a chemical anchor resin — not glue — for anything that carries load. |
| Leather | Contact cement for a permanent flexible bond, or a leather-craft PVA to hold pieces while you stitch them. |
| Silicone | Effectively only more silicone, and even that needs a primer — and any silicone residue left on a surface stops everything else sticking too. |
| Paper | A glue stick or PVA for everyday work; wheat starch paste or methylcellulose for anything you want to survive — and never tape. |
| Polycarbonate | A urethane or silicone adhesive is safest; solvent cements work but polycarbonate is unusually prone to stress cracking days later. |
Common questions
- Which glue works on foam?
- A foam-safe water-based adhesive or low-temperature hot melt — solvent adhesives dissolve polystyrene on contact.
- What should I avoid?
- Solvent-based contact adhesive or superglue accelerator on polystyrene Standard hot melt on thin foam sheet Assuming an adhesive that worked on upholstery foam is safe on packing foam
Related pages
- Which glue works on plastic? It depends entirely on which plastic — identify it first, because solvent cement is unbeatable on some and useless on others.
- Which glue works on polypropylene and polyethylene? Ordinary adhesives cannot wet these plastics at all. Use a polyolefin primer with cyanoacrylate, an MMA structural adhesive, or weld the plastic.
- Which glue works on wood? PVA wood glue for anything indoors; a water-resistant grade (Type I / D4) or polyurethane for anything that gets wet.
- Which glue works on metal? Two-part epoxy for anything structural, cyanoacrylate for small dry parts, and MMA where the surface cannot be properly prepared.
- Which glue works on ceramic? Two-part epoxy for anything that will be handled or loaded, cyanoacrylate for a clean break on a display piece — and neither is dishwasher-proof.
- Which glue works on shoes? A flexible shoe repair adhesive — polyurethane or a neoprene contact cement — never superglue, which cracks within a day of walking.
- Which glue works on fabric? A washable fabric adhesive or a fusible bonding web — and never superglue, which reacts with cotton violently enough to burn.
- Which glue works on glass? UV-cure glass adhesive for an invisible joint, clear epoxy where it must hold load, and neutral-cure silicone where it must stay flexible or wet.
- Which glue works on PVC pipe? PVC solvent cement with its matching primer — and PVC, CPVC and ABS cements are not interchangeable.
- Which adhesive should I use for tiles? A cement-based thin-set in almost every case; ready-mixed tub adhesive only on small dry walls, never on floors or in showers.
Sources
- Typical range compiled from manufacturer specifications — At One Place