Doable with the right adhesive
How to glue Aluminium to EPS (polystyrene foam)
The short answer
For Aluminium to EPS polystyrene foam, use a polystyrene-compatible adhesive whose manufacturer documentation names the foam. Soudabond Easy is the practical UK-available starting point for building-scale work; 3M 78 is a foam-specific spray alternative, and a solvent-free MS-polymer such as EVO-STIK Seriously Strong Stuff Ultimate is useful where a flexible bead and wet-service resistance matter. The exact aluminium finish is not directly tested in the cited documents, so this is a confidence-C assessed recommendation and a representative coupon test is required.
Why this bond behaves the way it does
The limiting substrate is polystyrene: an otherwise capable solvent adhesive can dissolve it. EPS has a weak, beaded surface, so broad adhesive coverage and light pressure reduce local tear-out. Soudal and 3M directly name the foam types, while their hard-substrate wording is aluminium/steel or generic metal rather than every finish in this pack.
What to use
Best choice
Polyurethane adhesive
Foam adhesive is directly documented for EPS/XPS and is sold in the UK; it suits broad building-scale bonds and cures without a solvent that dissolves polystyrene.
Watch out: Confidence C: foam chemistry is directly documented, but the exact metal grade or finish is not directly tested as a pair.
Also works
Spray adhesive
3M 78 directly names expanded and extruded polystyrene and says it will not dissolve the foam; its “metal” scope is generic and water/outdoor durability is not established here.
Watch out: Do not transfer another product’s substrate or environmental claims to this family.
Only in some cases
MS polymer
EVO-STIK Ultimate is solvent-free, flexible and documented for metals and foam polystyrene, with excellent water resistance; its exact metal-finish/polystyrene pair still needs a test.
Watch out: Do not transfer another product’s substrate or environmental claims to this family.
Not suitable
Solvent cement
Solvent cement is formulated to dissolve or weld selected thermoplastics and has no evidence for making a safe, durable metal-to-foam bond here.
Watch out: It may irreversibly attack the foam. Do not experiment on the finished part.
What to avoid
Avoid solvent cement and any unverified solvent-borne grab/contact adhesive, aerosol propellant or cleaner that is not explicitly polystyrene-safe. Avoid small hard adhesive blobs under load, excessive clamp pressure, and bonding over rust, loose paint, chalking zinc, failing plating or friable foam.
Preparing the surfaces
Aluminium
Degrease before abrading so oil is not spread. For WEST SYSTEM epoxy, dry-sand aluminium with 80-grit paper, remove residue and apply promptly. Structural production work may require a qualified etch or conversion treatment; do not improvise hazardous industrial etches from a general guide. Use the cited preparation as a starting point, but follow the chosen adhesive manufacturer's instructions and test the actual batch/finish. Avoid industrial acid or caustic etches unless a controlled, qualified process and safety system are in place.
EPS (polystyrene foam)
Brush or vacuum loose beads and dust without crushing the face. 3M warns that solvent-based all-purpose adhesives dissolve rigid polystyrene foam; use a foam-safe dispersion, low-melt or other product whose data sheet names EPS. Apply broadly and press lightly to spread load. Do not substitute an aggressive cleaner: test an offcut and stop if the foam softens, swells or loses its skin.
How to do it
1. Confirm the foam is EPS and trial the complete process on an offcut. 2. Prepare the metal without touching the cleaned bond area. 3. Brush or vacuum loose EPS beads without crushing the face. 4. Apply the selected foam-safe product exactly as its TDS directs, using broad beads or coverage rather than isolated points. 5. Assemble within the stated open time, press evenly, brace against movement and protect the uncured joint from water, frost and direct sun.
Working, clamping and cure times
For Soudabond Easy, wait for the stated tack stage, press for 30–60 seconds, leave at least one hour before loading and allow about 12 hours for full strength under the reference conditions. EVO-STIK Ultimate lists 17–24 hours to full cure. Temperature and humidity change cure rate.
If the conditions are harder
| Condition | Verdict | Notes |
|---|---|---|
| Outdoor use | Works with care | Use Soudabond Easy only behind a UV/weather-protective assembly, or use EVO-STIK Ultimate where its UK indoor/outdoor claim applies. Seal/protect foam edges and validate the exact metal finish. |
| Water and wet areas | Works with care | Soudabond Easy is water resistant but not watertight. EVO-STIK Ultimate has stronger wet/underwater wording, but exact pair testing and edge sealing are still required; do not infer a pressure-bearing immersion joint. |
| Heat and cold | Works with care | Soudabond Easy is listed from −40°C to +90°C and EVO-STIK Ultimate from −40°C to +100°C, but EPS/XPS dimensional stability and skin strength set a lower practical assembly ceiling. Validate thermal cycling at the actual design temperatures. |
Polystyrene can be irreversibly damaged by incompatible solvent or heat. The foam, its facing/skin or an existing coating may fail before the adhesive. Do not treat this as a structural or safety-critical joint without engineering validation.
Products that fit
Ordered by how well they suit this specific job. Nothing is ranked by what it pays.
Soudal Soudabond Easy
Polyurethane adhesive
UK-available foam adhesive documented for EPS and XPS; exact metal finish remains an assessed application.
Flexible, solvent-free UK MS-polymer documented for metals and foam polystyrene.
We may earn a commission from links on this page. It never changes which adhesive we recommend.
Related guides
- Aluminium to XPS foam board
- Copper to EPS (polystyrene foam)
- Aluminium to Pine
- Chrome plated metal to EPS (polystyrene foam)
- Aluminium to Plywood
- Cast iron to EPS (polystyrene foam)
Where this comes from
Reviewed 8 October 2026. Overall confidence: Inferred.
Sources used for this guide:
- 3M Polystyrene Foam Insulation 78 Spray Adhesive — Technical Data (TDS, Jun 2012)
- 3M Polystyrene Insulation Adhesive 78, Clear, 5 Gallon (MANUFACTURER_PAGE)
- EVO-STIK Seriously Strong Stuff Ultimate Strength — Technical Data Sheet (TDS, Jul 2018)
- G/flex 655 Thickened Epoxy Adhesive Instructions (TECHNICAL_MANUAL)
- Permabond 2K Surface Primer (APPLICATION_GUIDE)
- Soudabond Easy (MANUFACTURER_PAGE)
- Soudabond Easy — Technical Data Sheet (TDS, Sep 2019)
- Surface Preparation and Pretreatment for Structural Adhesives (TECHNICAL_MANUAL, Oct 2018)
- Soudal Soudabond Easy Gun Grade Adhesive Foam 750 ml (RETAILER_LISTING)
Always read the instructions and safety information supplied with the product you buy. Where they differ from anything here, follow the manufacturer.