Best Adhesive for Fixing Your Rubber Shoe Sole

Which glue repairs a rubber thong sole that has separated?

Selleys recommends a contact adhesive: Selleys Kwik Grip Horizontal or Selleys Kwik Grip Vertical Gel. Both are solvent-based contact adhesives, both list rubber among the materials they bond, and both are heat and water resistant — which is what a thong needs, given it spends its life wet and on hot ground.

The important thing about a contact adhesive is that it is not used like ordinary glue. You coat both surfaces, wait until the adhesive is almost dry, and only then bring the two faces together. They grab on contact and cannot be repositioned, so alignment has to be right the first time. Get that sequence wrong and the repair fails, whichever of the two you buy.

Which one to use

Both work for this repair. The difference is the consistency and what it suits.

Kwik Grip Horizontal is a liquid. It is the general choice for flat, horizontal work and bonds laminated plastics, rubber, leather, canvas, wood, cork, hardboard, metals and fibrous cement sheeting.

Kwik Grip Vertical Gel is a non-drip gel made for large vertical flat, close-fitting surfaces, and bonds rubber, cork, felt, leather, canvas, metals and veneers. The gel form is easier to control on a small, curved item because it does not run off the edges while you are spreading it.

The figures that govern the job

Property	Kwik Grip Vertical Gel	Kwik Grip Horizontal
Appearance	Beige / opaque gel	Solvent-based liquid
Open time	20–40 minutes	Approx. 20 minutes, max 40
Full cure	24 hours	24 hours
Heat resistance	130°C	130°C
Application temperature	10°C – 35°C	Do not use below 10°C
Coverage	0.25 m² per 40 g of one surface, depending on porosity	—
Pack sizes (Vertical Gel)	40 g tube; 400 g, 800 g and 3.2 kg cans	—

Figures are indicative data only and are not intended for the preparation of specifications.

Open time is the window that decides the repair. After you spread the adhesive you keep the two faces apart for roughly 20 minutes — until the adhesive is almost dry — and you must join them before 40 minutes have passed. Join too early and the solvent is still in the film, so the bond is weak and slow. Leave it past 40 minutes and the surface has gone off and will not grab.

Heat resistance of 130°C is the figure that makes this a sensible choice for footwear. A thong left on hot pavers or in a car boot gets hot enough to soften a lesser adhesive.

Maximum bond strength is reached after 24 hours. The joint grabs instantly, but the sole is not finished until the next day. Do not wear them the same afternoon.

How to do the repair

1. Make sure both surfaces are clean and dry. Beach sand, old adhesive and skin oil all sit between the glue and the rubber.
2. Apply Kwik Grip to both surfaces and spread it evenly, making sure the surfaces are completely covered. A missed patch is where the sole will start peeling again.
3. Keep the surfaces apart until the adhesive is almost dry — approximately 20 minutes, no more than 40.
4. Position the sole carefully while the surfaces are still held apart. When the edges are perfectly aligned, work from one edge and press the surfaces firmly together. It grabs immediately on contact.
5. Secure the bond by running a roller over the bonded surfaces, or by hammering the surface from the centre outwards using a padded block. This is what develops the bond — contact adhesive needs pressure, not time under a clamp.
6. Leave it 24 hours for maximum bond strength. Clamping may be necessary if the sole has warped or curled away from the body.

For a small area like a thong sole, the data sheet also allows a wet bonding method: apply Kwik Grip to one surface, bring the surfaces together straight away, and clamp until dry. This is the easier method if the separated piece is small and you can clamp it properly.

Limitations — read these before you start

• Not for polyethylene or polypropylene plastics. Many thongs are moulded foam rather than natural rubber. If yours is a plastic foam rather than the rubber described here, test on a hidden spot first, or use Selleys All Plastics instead.
• Test compatibility first. Kwik Grip's own tips say to ensure compatibility with the materials being bonded, testing on an inconspicuous area or confirming with the manufacturer — some materials are incompatible with solvent products.
• Do not use below 10°C. The product may also thicken in storage at low temperatures; if that happens, warm it to room temperature for 24 hours, or stand it in the sun or a bowl of hot water for a short period with occasional stirring.
• Kwik Grip Horizontal is not suitable for rough or ill-fitting surfaces. Contact adhesive bonds where the two faces touch, so it needs close-fitting surfaces.
• Ensure any leftover product in a container is completely dry before disposal.

Clean up

Clean up wet adhesive with mineral turps, and do it straight away. Cured Kwik Grip is extremely difficult to remove — once it has set, the only practical method is scraping or other mechanical means, and solvents will not readily shift it. There is more detail on that in how to remove Kwik Grip once dry.

Safety: the open time is also a vapour release

Kwik Grip Horizontal is classified hazardous with the signal word Danger: H225, highly flammable liquid and vapour; H319, causes serious eye irritation; H315, causes skin irritation; and H336, may cause drowsiness or dizziness. That last one is not a footnote on this job — it follows directly from how a contact adhesive is used.

The method on this page has you deliberately evaporating solvent for twenty to forty minutes. Every other adhesive in the range cures with the joint closed. A contact adhesive works the other way: you coat both faces and leave them open while the solvent flashes off, because that is what creates the grab. The open time is not dead time — it is the product releasing its entire solvent load into the room while you sit next to it holding a thong.

Two things follow. Do this outside, or at a bench with a window and a through-draught, not at the kitchen table with the door shut. And remember that H225 vapour is heavier than air: it sinks and travels along the floor, so a pilot light, a gas heater or a bar radiator at skirting height is an ignition source even if it is across the room. No smoking, no soldering, no heat gun in the same space.

The cold-weather tip above needs reading with H225 in mind. If the adhesive has thickened in storage, this page offers warming it — room temperature for 24 hours, or standing the container in the sun or a bowl of hot water with occasional stirring. Hot water or ambient warmth only. Never a stove, an oven, a heat gun or a naked flame, and never a sealed container being heated.

H319 matters at the moment you are least expecting it: prising a lid off a can, or stirring thickened adhesive, both flick product upwards. Eye protection while the can is open. Nitrile gloves deal with H315, and they also save you from the clean-up problem the page describes, because cured Kwik Grip on skin is as stubborn as cured Kwik Grip anywhere else.

Switching product does not solve the flammability here. If your thongs turn out to be polyethylene or polypropylene, this page sends you to All Plastics — also Danger, H225, with H319 and H336 as well. Both routes are solvent-borne, so ventilation and ignition control are the controls either way, not the product choice. Mineral turps for clean-up is flammable too: spread used rags out to dry rather than binning them balled up.

Poisons Information Centre — 131 126 in Australia, 0800 764 766 in New Zealand.

Common questions

Do I put glue on one surface or both?

Both, for the standard contact method — spread evenly and cover completely. For small areas or porous surfaces you can use the wet bonding method instead: apply to one surface, join immediately, and clamp until dry.

How long do I wait before pressing the pieces together?

Approximately 20 minutes, and no more than 40. You are waiting for the adhesive to be almost dry to the touch.

Can I reposition the sole after it touches?

No. Kwik Grip grabs immediately on contact. Align the edges before the surfaces meet, then press from one edge across.

How long before I can wear them?

Maximum bond strength is reached after 24 hours. Give it the full day.

Will the repair survive getting wet?

Both Kwik Grip products form a heat and water resistant bond.

Will it survive being left in the sun?

Heat resistance is rated at 130°C for both products.

Can I use Kwik Grip in the cold?

No. Do not use below 10°C. The application temperature range for Vertical Gel is 10°C to 35°C.

What if my thongs are foam plastic rather than rubber?

Kwik Grip is not for polyethylene or polypropylene plastics. Test an inconspicuous area first, or use Selleys All Plastics for those materials.

Is there other guidance on shoe repairs?

Yes — see gluing shoe soles and how to repair shoes.