What is Selleys Aquadhere Exterior, and where should you use it?

Selleys Aquadhere Exterior is an industrial-grade polyaliphatic cross-linking PVA wood glue, developed for professional woodworkers and craftsmen. It produces bonds stronger than most woods and it is weatherproof, which is what makes it suitable for exterior projects where a standard interior PVA would fail.

"Bonds stronger than most woods" is worth taking literally: in a well-made joint, the timber fails before the glue line does. That shifts the question from whether the adhesive is strong enough to whether the joint is close-fitting and properly clamped, which is where this glue's directions put all their emphasis.

One thing to be clear about before choosing it: weatherproof is not the same as immersible. It is not suitable for below waterline applications or continuous submersion.

Technical specification

Property	Typical result
Technology	PVA
Colour	Off-white, dries clear with a yellow tinge
Coverage	Approximately 5m² per litre
pH	2–3
Viscosity	2000–3500 cP
Clamp time	Softwoods: 30 minutes Hardwoods: 1 hour
Max bond time	24 hours

Available in 250mL, 500mL, 1L and 4L bottles. Indicative data only, not intended for the preparation of specifications.

What the key numbers mean in practice

Clamp time: 30 minutes for softwoods, 1 hour for hardwoods. The difference is not arbitrary. Dense hardwoods absorb water from the adhesive more slowly, so the glue line takes longer to develop holding strength. Clamping a hardwood joint to the softwood schedule is one of the more common ways a joint ends up weak. Selleys also notes that longer clamping times may be required for joints under high stress.

Maximum strength at 24 hours — and do not stress the joint before then. Getting the clamps off after an hour does not mean the assembly is ready to be worked, loaded or moved roughly. Selleys adds that maximum strength takes longer in cold, damp conditions or with dense timbers, so a hardwood project glued up in a cold garage in winter needs more than a day.

Coverage approximately 5m² per litre. Useful for laminating and veneering, where you are spreading over area rather than running a bead. A 1L bottle covers roughly five square metres of glue face; a 4L bottle, about twenty. Remember you only coat one surface.

pH 2–3. This is an acidic adhesive, which is the reason behind two of its limitations: keep it away from iron and steel, and expect staining if it is contaminated with rust or meets the tannins in many timbers.

Where to use it

Aquadhere Exterior is ideal for:

• Dowelling
• Joinery
• Laminating
• Veneering
• Cabinet and furniture making

It can be chiselled, routed or turned once cured, and it will stick softwoods, hardwoods, particleboard, chipboard, plywood and MDF.

Its stated features are excellent performance properties for repairs or building projects, suitability for exterior use in non-structural applications, non-toxic, weather resistant, and easy clean-up with water.

How to apply it

1. Make sure the surfaces to be bonded are close fitting, dry and clean. Ensure the surface is dry before applying the product — a damp joint face dilutes the glue line.
2. Shake the bottle before use.
3. Apply adhesive liberally to one surface only.
4. Clamp for 30 minutes for softwoods, 1 hour for hardwoods. Do not stress the joint for 24 hours.
5. Wipe off excess adhesive with a damp cloth while it is still wet.
6. Allow 24 hours for maximum strength — longer in cold, damp conditions or with dense timbers.

To fill small gaps, Aquadhere can be mixed with sawdust. Using sawdust from the timber you are working gives a filled joint that takes finish closer to the surrounding surface.

Working with the viscosity

At 2000–3500 cP this is a moderately thick adhesive — thick enough to stay put on a horizontal glue face and to hold a bead on a dowel, but still fluid enough to spread with a brush or a spreader for laminating and veneering. That is the reason it suits both jobs on the uses list: a dowel or a mortice needs a glue that will not run out of the hole, while a veneer needs one that will spread thinly and evenly over area.

The instruction to shake the bottle before use matters for the same reason. A PVA that has stood for months is not perfectly uniform, and an unshaken bottle can dispense inconsistently across a large glue face — which shows up as a patchy bond on exactly the wide-area work where you would least like to find it.

Note the wording of the direction too: apply liberally, but to one surface only. Generous coverage on a single face, then closed and clamped, is what Selleys specifies — not a thin coat on each side, and not a starved joint.

Limitations — where Aquadhere Exterior should not be used

• Not recommended for joints that are subjected to constant high stress.
• Not suitable for below waterline applications or continuous submersion. It is weatherproof, not immersible.
• Avoid contaminating it with iron and steel — nails, for example. Do not stir it with a steel tool or store it near rusting hardware.
• It will stain brown or black if contaminated with rust (iron oxide), or in the presence of tannins in many woods. On oak, cedar and other high-tannin timbers this is a visible-finish risk, not just a theoretical one.
• Not suitable for coated or vinyl wallpapers, per the product page.
• It will not accept stain without sanding, per the product page. Sand any squeeze-out back before you stain, or it will show as a pale patch through the finish.

Selleys also notes that painting or varnishing constructions made of porous softwoods will improve the resistance of the bonds to water exposure. On an exterior softwood project, finishing the timber is part of protecting the glue line.

Clean up

Uncured product may be removed with water — wipe off excess with a damp cloth while it is still wet, which is by far the easiest moment to do it. Cured product can be sanded or scraped. The product page adds that cured adhesive can be re-softened with steam or hot water.

Hazard classification

Selleys Aquadhere Exterior is not classified as hazardous under the criteria of Safe Work Australia GHS 7. No signal word is assigned and there are no hazard statements, because the product does not meet the threshold for any GHS hazard class. It is not classified as Dangerous Goods by the Australian Code for the Transport of Dangerous Goods by Road & Rail or by New Zealand NZS5433 either.

That is a definitive statement from the product's own safety data sheet rather than an absence of information, and it lines up with the "non-toxic" claim in the feature list above.

What is in it

Chemical entity	CAS number	Proportion (w/w)
Aluminium chloride, hexahydrate	7784-13-6	1–10%
Non-hazardous or below reporting limits	—	Balance

One declared ingredient, at under ten percent, in a PVA dispersion that is otherwise water and polymer. The aluminium salt is the cross-linker — it is what turns an ordinary interior PVA into a D3 exterior-grade adhesive by tying the polymer chains together as the glue dries, which is what the "polyaliphatic cross-linking" description on the label is referring to.

It is also the source of the pH of 2–3 quoted in the specification above, since an aluminium salt in water is acidic. That single fact explains two of the limitations already listed on this page, and they are worth connecting: keep the adhesive away from iron and steel, and expect brown or black staining where it meets rust or the tannins in timbers such as oak and cedar. An acidic adhesive in contact with steel produces iron salts, and iron reacting with tannin is the classic black stain on oak. Those are staining problems rather than safety problems, but they are the same chemistry.

Being unclassified does not mean there is nothing to think about. An adhesive at pH 2–3 is still acidic enough to be unpleasant in an eye, and PVA is easy to get on your hands and easy to forget about. Wipe excess off with a damp cloth while it is wet as the directions say, rinse your eyes with water if any gets in them, wash your hands afterwards, and keep it away from food. If you sand a cured glue line, that is ordinary sanding dust and deserves the ordinary response — a mask, and eye protection.

Common questions about Selleys Aquadhere Exterior

How long do I clamp the joint?

30 minutes for softwoods, 1 hour for hardwoods. Longer clamping times may be required for joints under high stress.

When can I use the assembly?

Do not stress the joint for 24 hours. Maximum strength is attained in 24 hours, but longer in cold, damp conditions or with dense timbers.

Do I glue both faces?

No. Apply adhesive liberally to one surface only.

Can I use it outdoors?

Yes — it is weatherproof and suitable for exterior use in non-structural applications. It is not suitable for below waterline applications or continuous submersion.

How much will a bottle cover?

Approximately 5m² per litre.

What sizes does it come in?

250mL, 500mL, 1L and 4L bottles.

What colour is it when dry?

Off-white in the bottle, drying clear with a yellow tinge.

Can I stain over it?

The product page states it will not accept stain without sanding. Sand the glue line back before staining.

Why has my joint gone black?

Aquadhere stains brown or black if contaminated with rust (iron oxide) or in the presence of tannins in many woods. Keep it away from iron and steel, including nails and steel stirrers.

Can I use it to fill a small gap?

Yes — Aquadhere can be mixed with sawdust to fill small gaps.

Can I use it for structural work?

It is stated as suitable for exterior use in non-structural applications, and not recommended for joints subjected to constant high stress.

How do I clean it up?

Wipe off excess with a damp cloth while wet. Uncured product comes off with water; cured product can be sanded or scraped.

Will it work on MDF and particleboard?

Yes — softwoods, hardwoods, particleboard, chipboard, plywood and MDF.

Can I turn or rout the piece after gluing?

Yes. Aquadhere Exterior can be chiselled, routed or turned. Allow the full 24 hours before working the joint.

Is it toxic?

Selleys lists non-toxic among the product's features.

Do I need to shake it?

Yes — shake the bottle before use.

Does the timber need to be dry?

Yes. Surfaces must be close fitting, dry and clean, and Selleys repeats this as a tip: ensure the surface is dry before applying the product.

For interior-only work see Aquadhere Interior; for a moisture-curing polyurethane that bonds timber to a wider range of materials, see Aquadhere Durabond. The wood glue guide covers how to choose.