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Polystyrene foam glue vs plastic cement

Updated: 23 October 2026

You have one search term, polystyrene, and two bottles that look equally plausible on amazon.co.uk. One is a foam contact adhesive. The other is a plastic cement for hard kit styrene. They are not two strengths of the same glue. Polystyrene foam glue cushions and bonds foam cells. Plastic cement dissolves and welds dense kit plastic. This page makes that one choice. Prices and the full table are on the [polystyrene glue comparison](/hub/fillers-adhesives-and-sprays/polystyrene-glue). Figures are amazon.co.uk listings from 19 October 2026. Peter F. did not melt a scrap in a lab. A qualifying purchase can earn us a commission at no extra cost to you.

You have one search term, polystyrene, and two bottles that look equally plausible on amazon.co.uk. One is a foam contact adhesive. The other is a plastic cement for hard kit styrene.

Our top picks

UHU UHU POR, pack of 2

Best overall

UHU UHU POR, pack of 2
8.9/10about £11.82
View offer
UHU UHU por 50 ml

Rank 2

UHU UHU por 50 ml
9.4/10about £6.75
View offer
Revell Revell Contacta Professional

Rank 3

Revell Revell Contacta Professional
9.1/10about £6.47
View offer
On this page
  1. 1.One word, two materials
  2. 2.What plastic cement does
  3. 3.What foam contact adhesive does
  4. 4.Choose in one glance
  5. 5.Why review counts mislead

One word, two materials

Expanded polystyrene foam is mostly air held in thin cell walls. Hard kit polystyrene is a dense moulding. Both can share the polymer family name, which is why the search results blur. Packaging beads, foamboard, Depron and some RC airframes sit on the foam side. Fuselage halves, tank tracks and miniature bases sit on the kit side. A scrap you can crush into a soft bead is foam. A shiny scrap that rings when tapped is kit plastic. Guessing from the word polystyrene is how a scenery board gets a crater, or a kit joint gets a rubbery film that never welds. Felt tacky glue and board adhesives are not this swap. They sit on the polystyrene glue buying guide.

What plastic cement does

Revell Contacta Professional is the kit cement in this set: a 25 ml needle bottle at £6.47, 4.5 from 13,778 amazon.co.uk reviews. The listing names plastic and a welding effect. Solvent in the mix softens the styrene so the faces fuse as the solvent leaves. That is useful on a tight kit joint and destructive on foam cells, which have nothing dense left to weld once the walls collapse. Reviewers praise the fine needle on small parts and complain about clogging, leaks into the cap and needles that pull out. Those are kit-bench problems. They are not evidence that the bottle is gentle on Styrofoam. Polystyrene cement dissolves EPS and XPS on contact. Poly cement for kits and expanded-polystyrene glue for foam are separate products for that reason.
UHU UHU POR, pack of 2

Testsieger

UHU UHU POR, pack of 2
8.9/10about £11.82
View offer

What foam contact adhesive does

UHU POR is the foam contact adhesive in this set: £6.75 for 50 ml with 4.6 from 847 reviews, or £11.82 for the twin pack with 4.7 from 57. The maker describes a film that bonds expanded polystyrene without the melt pattern of ordinary all-purpose solvent glue, on both faces, joined when tacky. 3M UK still warns that solvent all-purpose adhesives dissolve rigid polystyrene foam. POR is solvent-based and highly flammable. Foam-safe in the maker's sense is not solvent-free. Reviewers use it on foamboard, scenery and RC foam when they follow the contact method. At least one UK review still reported foam attacked, so a scrap test beats a title. Shed insulation pressed as if it were PVA did not hold. The twin pack excludes PP, so polypropylene foam (EPP) is not an automatic yes.

Choose in one glance

If the part is hard kit styrene, buy cement such as Contacta and keep it away from foam. If the part is expanded polystyrene foam, foamboard or similar hard foam, buy a foam contact adhesive such as POR and use both faces. If the part is felt on craft foam, neither bottle is the first pick; that is Aleene's lane. If the part is an insulation board on a wall, neither craft tube is the class you need. Hobby builds that mix foamboard wings and hard styrene detail need both chemistries on the bench, labelled, not one polystyrene glue asked to do both. That bench map continues on polystyrene glue for models and RC.

Why review counts mislead

Contacta's review file is enormous because plastic kits are a huge hobby category. That popularity does not transfer to foam. A buyer who sorts amazon.co.uk by ratings and grabs the needle bottle for white foam has followed the wrong signal. UHU por's hundreds of UK notes are the foam signal in this set. A 4.8 from five reviews on a generic foam bottle is not a third chemistry and not a reason to ignore the POR file. Titles mislead in the other direction too. The twin POR pack title can read like a plastic glue while the bullets specify expanded polystyrene. Read the material line, then the method, then the stars. Stars last.

Common questions

Is Contacta a foam glue because it says polystyrene?
No. Contacta is plastic cement for hard kit styrene. The polymer family name overlaps with foam, but the chemistry is a solvent weld, not a foam contact film.
Will UHU POR weld a plastic kit the way Contacta does?
No. POR is a contact adhesive film for foam and named materials. It is not a cold weld for hard kit joints. Use cement for kits.
Can I use a tiny amount of cement on foam if I am careful?
Care does not rebuild collapsed cells. Solvent cement is the wrong class for expanded polystyrene foam. Use a foam-safe contact adhesive or another maker-stated foam chemistry.
Which should I buy if I build both kits and foam scenery?
Both, kept separate. Cement for hard styrene kits, foam contact adhesive for expanded polystyrene and foamboard. One bottle will not cover both jobs safely.
Does a higher amazon review count mean safer on foam?
No. Review count follows how many people buy that product for its main job. Kit cement can outrank foam adhesive on volume without being foam-safe.
Is POR solvent-free?
No. POR is solvent-based and highly flammable. The maker's claim is that the blend is chosen not to attack expanded polystyrene, which is different from being solvent-free.

Related pages

Best polystyrene glue

How to use polystyrene glue

Polystyrene glue

Polystyrene glue buying guide for foam, kits or felt

Polystyrene glue for model kits, RC foamboard and Depron

Sources

Public UK and maker sources used for this comparison. amazon.co.uk prices, stars and review counts were taken from the listings on 19 October 2026. The score sheet is dated 21 October 2026.

  1. UHU POR product page (retrieved 19 October 2026)
  2. UHU POR technical sheet (retrieved 19 October 2026)
  3. UHU POR datasheet: does not attack the foam (retrieved 19 October 2026)
  4. Revell model-building adhesives (retrieved 19 October 2026)
  5. HSE SR22, solvent-based adhesives (retrieved 19 October 2026)
  6. Written answer: polystyrene ceiling tiles and Part B (retrieved 19 October 2026)
  7. 3M UK, bonding foam (retrieved 19 October 2026)
  8. Aleene's Felt and Foam tacky glue (retrieved 19 October 2026)