Which glue sticks to silicone?
Which glue sticks to silicone?
Effectively only more silicone, and even that needs a primer — and any silicone residue left on a surface stops everything else sticking too.
Silicone has a surface energy of roughly 20-24 mN/m, in the same range as PTFE and well below what any conventional adhesive needs in order to wet it, and its backbone is chemically inert with nothing for an adhesive to react with. That is precisely why it is used for seals, baking mats and release surfaces. The practical trap this creates has nothing to do with gluing silicone deliberately: silicone contamination transfers easily, so old sealant residue in a bath joint, or overspray from a silicone lubricant, leaves a surface that new sealant, paint and adhesives all refuse to stick to. Removing it means physically cutting the residue away and then cleaning with a dedicated silicone remover, because wiping with solvent tends to spread a thinner film over a wider area.
The options, ranked
| Option | Good at | Bad at |
|---|---|---|
| Fresh silicone with a silicone primer | The only reliable route: the primer gives the cured surface something reactive for the new silicone to bond to. | Primers are brand-specific, add a step and a wait, and the bond is still modest. |
| Silicone-specific cyanoacrylate primer | Makes superglue hold on silicone rubber well enough for small non-structural repairs. | Brittle bond on a very flexible substrate, so it fails in peel. |
| Mechanical fixing | A clamp, a band or a moulded-in feature will always outperform adhesive on silicone. | Not possible on a seal or a thin membrane. |
| Replacing the part | Usually cheaper and always more reliable than bonding cured silicone. | Not an option for a moulded-in component. |
Technique that changes the outcome
- Cut old sealant away with a sharp blade rather than trying to dissolve it
- Scrub the joint with a proprietary silicone remover, then wipe with isopropanol and let it dry
- Where you must bond to cured silicone, abrade lightly and use the primer the sealant maker specifies
- Test on a hidden section; adhesion to silicone varies with the curing system used in the original part
What goes wrong
- Trying to paint over silicone sealant — no household paint adheres to it
- Applying new sealant over old; the joint fails at the interface within months
- Using silicone spray lubricant anywhere near a surface that will later be painted or glued
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. |
| Paper | A glue stick or PVA for everyday work; wheat starch paste or methylcellulose for anything you want to survive — and never tape. |
| Foam | A foam-safe water-based adhesive or low-temperature hot melt — solvent adhesives dissolve polystyrene on contact. |
| 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 sticks to silicone?
- Effectively only more silicone, and even that needs a primer — and any silicone residue left on a surface stops everything else sticking too.
- What should I avoid?
- Trying to paint over silicone sealant — no household paint adheres to it Applying new sealant over old; the joint fails at the interface within months Using silicone spray lubricant anywhere near a surface that will later be painted or glued
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