Best Glue To Fix Polystyrene Pieces

What is the best glue for sticking polystyrene to wood indoors?

Selleys names four products for this job, and the thing they have in common is the reason they work: they are all water-based, they bond to both polystyrene and timber, and they are safe to use on polystyrene. The four are Selleys Aquadhere Interior and Selleys Aquadhere Exterior (both PVA wood glues), Selleys All Fix Big Jobs, and Selleys Liquid Nails Fast Grab.

Which one you reach for depends on how heavy the polystyrene pieces are and whether they need to hold on a vertical face. For light offcuts of packing foam glued flat to a board, a PVA is enough. For anything with weight, or anything you are sticking to a wall, Liquid Nails Fast Grab is the one with published grab and strength figures behind it — its technical data sheet lists polystyrene foam among the materials it is made to bond.

Why water-based matters here

Selleys' advice on this question is specific about the chemistry: the recommended glues are water-based, and that is what makes them safe on polystyrene. It is worth taking that constraint seriously rather than substituting whatever adhesive is already in the shed. Selleys' own contact-adhesive data sheets carry a standing instruction to check compatibility with the materials being bonded, and to test on an inconspicuous area before committing — advice that exists because solvent-borne products do not suit every substrate.

Since the job is indoors, you also do not need weather resistance, which widens the field. Aquadhere Interior is a PVA made for interior woodworking; it is not waterproof and is not intended for structural use, so an indoor decorative or display job is exactly its territory.

The options compared

Selleys Liquid Nails Fast Grab

This is the strongest of the four for anything with weight in it. Its published figures are up to 100 kg/m² of instant grab on application, a tensile shear bond strength greater than 1.5 MPa (AS 2329-1999E), and a final bond strength of up to 500 tonnes/m² after seven days. It cures in 72 hours under normal conditions, and it is formulated not to drip, sag or string, which is what makes it workable on a vertical surface.

The instant grab is the practical advantage. Polystyrene is light but bulky, and a foam block glued to a wall will slide down a PVA bead while it dries. Fast Grab holds it where you put it.

One limitation to note: Liquid Nails Fast Grab is for interior and sheltered exterior applications only — it must be protected from moisture. For your indoor job that is not a constraint, but do not carry the recommendation outside to an exposed position.

Selleys Aquadhere Exterior

An industrial-grade cross-linking PVA that produces bonds stronger than most woods and is weatherproof. Coverage is approximately 5 m² per litre, and it comes in 250 mL, 500 mL, 1 L and 4 L bottles. Apply it liberally to one surface only, then clamp — 30 minutes for softwoods, one hour for hardwoods — and do not stress the joint for 24 hours. Maximum strength is reached at 24 hours, longer in cold, damp conditions or with dense timbers.

Selleys Aquadhere Interior

The interior-only PVA. It bonds timber, MDF, plywood and particle board, cleans up with water while wet, and should not be used below 5°C. It is not waterproof and not for structural use — fine for a display piece, wrong for anything load-bearing or damp.

Selleys All Fix Big Jobs

Named by Selleys as suitable for this job. There is no published technical data sheet for it in our reference set, so check the pack for the application detail, drying time and pack size before you buy.

How to get a good bond

Make sure both surfaces are clean, dry and free of dust, grease and loose particles. Polystyrene packing foam usually has a crumbly, dusty skin from being cut — brush or wipe that off, because glue sticks to it rather than to the foam beneath.
If you are using a PVA, apply it liberally to one surface only. Applying to both just squeezes out.
Bring the surfaces together and clamp or weight them. With Aquadhere Exterior, clamp for 30 minutes on softwood and an hour on hardwood.
Wipe off any excess with a damp cloth while it is still wet. PVA is far easier to remove now than later.
Leave the joint alone. Do not stress an Aquadhere Exterior joint for 24 hours; give Liquid Nails Fast Grab 72 hours to cure.

Clamping polystyrene needs a light touch — the foam crushes long before the timber does. Weights, or clamps with a wide packing block spreading the load, are better than a G-clamp bearing on a small area.

Limitations worth knowing

Aquadhere Exterior is not recommended for joints under constant high stress, and is not suitable for below-waterline applications or continuous submersion. Keep it away from iron and steel — nails and the like — because it stains brown or black if contaminated with rust, and the tannins in many timbers will discolour it too.
Aquadhere Interior is not waterproof, not water resistant and not for structural use. Do not use below 5°C.
Liquid Nails Fast Grab is for interior and sheltered exterior use only, protected from moisture.

Common questions

Will the glue melt or eat the polystyrene?

Not the products Selleys recommends here. All four are water-based and Selleys states they are safe to use on polystyrene. Liquid Nails Fast Grab's data sheet lists polystyrene foam as a material it is made to bond.

Which one holds best on a vertical surface?

Liquid Nails Fast Grab. It gives up to 100 kg/m² of instant grab and is formulated not to drip, sag or string, so the piece stays where you press it instead of sliding while a PVA dries.

How long before I can handle the job?

With Aquadhere Exterior, clamp for 30 minutes on softwood or an hour on hardwood, then leave the joint unstressed for 24 hours. Liquid Nails Fast Grab cures in 72 hours, though it grabs immediately.

Do I put glue on both surfaces?

With Aquadhere Exterior, no — apply liberally to one surface only. Contact adhesives are a different method entirely and are not what Selleys recommends for polystyrene.

Can I use the same glue outdoors?

Aquadhere Exterior is weather resistant and made for exterior projects. Aquadhere Interior is interior only, and Liquid Nails Fast Grab is limited to interior and sheltered exterior positions.

How much Aquadhere Exterior will I need?

Coverage is approximately 5 m² per litre. It is sold in 250 mL, 500 mL, 1 L and 4 L bottles.

How do I clean up the excess?

Wipe uncured PVA off with a damp cloth while it is still wet. Once cured, Aquadhere has to be sanded or scraped off.

What if the pieces are heavy or the joint is structural?

None of these is a structural adhesive. Aquadhere Interior is expressly not for structural use, and Aquadhere Exterior is not recommended for joints under constant high stress. Use mechanical fixings for anything load-bearing.

Is there general guidance on gluing polystyrene?

Yes — see how to glue polystyrene for the wider question, and the Selleys wood glue range for the full PVA line-up.

What is the best glue for sticking polystyrene pieces to wood indoors?

Selleys Liquid Nails Fast Grab is the recommended adhesive for bonding polystyrene pieces (such as repurposed packing material) to wood in an indoor job.

Why is Selleys Liquid Nails Fast Grab suitable for this indoor polystyrene-to-wood job?

It effectively bonds polystyrene foam and provides strong adhesion to wood, and it features a low-odour, water-based formulation that makes it a good choice for indoor applications.

How quickly does Selleys Liquid Nails Fast Grab bond materials together?

It has a high initial grab capability that allows for rapid bonding with reduced wait times during application, while still providing strong, durable long-term bonding strength.

What steps should be followed when applying this adhesive to bond polystyrene to wood?

Ensure both the polystyrene pieces and wood surfaces are clean and dry, apply the adhesive according to the product directions, press the materials together firmly, and take advantage of the fast grab to position pieces quickly without extended clamping.

Which Selleys products should be avoided for bonding polystyrene foam?

Pro-Trade Construction Adhesive should be avoided since it is not suitable for bonding polystyrene foam despite being a multipurpose construction adhesive, and Selleys Kwik Grip High Temp Spray Adhesive should also be avoided as it is not compatible with polystyrene foam.

Who publishes this adhesive advice page and what is their background?

The page is published by Selleys, an Australian adhesives, sealants and fillers brand founded in 1939 in Sydney, Australia by Martin Selley, and is a division of DuluxGroup (Australia) Pty Ltd.