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Gun foam vs straw foam: when the extra kit is worth it

Updated: 23 October 2026

You used a straw can, watched the nozzle block. Gun foam vs straw foam asks whether the next gap is still one afternoon or the start of a habit. In the [expanding foam comparison](/hub/fillers-adhesives-and-sprays/expanding-foam) the straw cans will not screw onto a gun, and the gun cans arrive without one, except a combi box whose reviews dispute the carton. Prices are the amazon.co.uk figures from 19 October 2026. A qualifying purchase can earn a commission at no extra cost to you. The job choice is the [expanding foam filler buying guide](/hub/fillers-adhesives-and-sprays/expanding-foam/sub/expanding-foam-buying-guide). The bead is on [how to use expanding foam](/hub/fillers-adhesives-and-sprays/expanding-foam/sub/expanding-foam-how-to-use).

You used a straw can, watched the nozzle block. Gun foam vs straw foam asks whether the next gap is still one afternoon or the start of a habit.

Our top picks

Soudal Soudal Soudafoam Gap Filler 750 ml

Best overall

Soudal Soudal Soudafoam Gap Filler 750 ml
8.7/10about £7.19
View offer
Soudal Soudal gap-filler kit, 6 cans

Rank 2

Soudal Soudal gap-filler kit, 6 cans
6.8/10about £47.25
View offer
Gorilla Filler Gorilla Filler 500 ml

Rank 3

Gorilla Filler Gorilla Filler 500 ml
9.2/10about £6.75
View offer
On this page
  1. 1.What changes when you leave the straw
  2. 2.What you must buy with the can
  3. 3.When a cheaper can inside a box is cheaper
  4. 4.The kit, and cans that will not fit

What changes when you leave the straw

A straw can needs no gun. You shake it, fit the tube, and fill about half the joint. Penosil’s UK comparison says straw foam post-expands more, yields less, and is thrown away once opened. On Gorilla Filler at £6.75, 4.3 from 7,701, the nozzle blocks, comes off, or leaks if you try later. A gun lets you set the screw, fill nearer 60 to 70 per cent, or about 65 per cent on Soudal’s Gun Gap Filler page, and stop between gaps if the can stays on the gun. Reviews on the Soudal 750 ml at £7.19, 4.6 from 411, prefer that control, and they report a leak if the gun comes off and goes back on. Soudal’s Genius Gun claim of up to six weeks is not this batch. A straw valve will not adapt to a gun.

What you must buy with the can

The single gun can at £7.19 includes no gun and no cleaner. The included-components line says n.a. Six-pack reviews say a clogged gun stays clogged, and that skipping the cleaner ruins it. One review described a can that split at the seam during shaking, so a gun does not remove every aerosol failure. For one gap today, the straw side is still the £6.75 Gorilla Filler, or the stone twin at £10.82 if you will open both cans the same day. The champagne Soudal twin at £12.99 is also a straw product, listed as not water resistant. It does not become gun foam because the brand is Soudal.
Soudal Soudal Soudafoam Gap Filler 750 ml

Testsieger

Soudal Soudal Soudafoam Gap Filler 750 ml
8.7/10about £7.19
View offer

When a cheaper can inside a box is cheaper

On this snapshot the division is not a quote you can still click. One Soudal 750 ml gun can is £7.19, gun extra. The six-pack at £28.99 is about £4.83 a can, gun extra. The VSA20AA box at £47.99 is about £4 a can, gun extra, and the carton weighs 12.5 kg. Some reviews report poor propellant. The other twelve-pack at £52.44 is about £4.37 a can, 4.7 from 53 reviews. A cheaper can inside a box is cheaper only if you will use the box. Three pipe gaps do not justify a case of unused foam and a gun you have not cleaned.

The kit, and cans that will not fit

The combi box, part 152990, is £47.25 and the title says six 750 ml cans, one gun and one cleaner. Some reviewers describe an adjustable gun. Others say the gun was not Soudal, with Bondit named once, and that the cleaner was missing. The item weight is printed as 550 g, which is not six 750 ml cans, and a bullet says Brand: Truly PVC. Gorilla Filler will not fit that gun. Paint Factory at £5.82 is a straw can with a holed tube, not a cheap way into gun foam. Buy straw foam for one gap you will finish today. Buy the single £7.19 gun can, plus a gun and cleaner, until you know you will empty a six-pack. Buy the kit only after you have checked the gun and the cleaner against the title. Leave both formats alone on a frame that can bow, or on a detail that has to be a fire stop.

Common questions

When is a straw can enough?
When you have one gap, you will finish it in the same session, and you can throw away what is left in the tube. That is the Gorilla Filler pattern at £6.75. It stops being enough when you are opening a fresh can every time you find another hole.
What extra do I have to buy with gun-grade foam?
A foam gun and a cleaner. The £7.19 Soudal can, the £28.99 six-pack and both twelve-packs leave the gun out. Cleaner is what the six-pack reviews say saves the gun after use.
Can I pause a gun can until tomorrow?
You can leave it on the gun if you then keep that gun clear, which is the point of the cleaner. Reviews on the single can report a leak after the gun is removed and refitted. A straw can does not get the same pause. The tube sets.
Will Gorilla Filler fit my foam gun?
No. Reviews on the 500 ml 151 Products can say it will not work with a separate applicator gun. The stone twin and the Ferris cans are straw products as well. Buy a can that is titled gun grade if the gun is the tool you want to use.
Is the combi box the easy way to get a gun?
It is the only listing here that puts a gun in the title, at £47.25. Reviews say the gun was sometimes another brand and that the cleaner was missing. Check the carton. If the cleaner is absent, the gun is on a short life.
How much cheaper is a can inside a six-pack?
On this snapshot, £28.99 divided by 6 is about £4.83, against £7.19 for one gun can. You save about £2.36 a can and you still buy the gun and the cleaner. The saving appears only if six cans is a quantity you will use.

Related pages

Expanding foam around windows

Best expanding foam

Expanding foam

Expanding foam filler guide: straw, gun or neither

How to use expanding foam without emptying the can

Sources

Public UK sources used for this comparison. amazon.co.uk prices, stars and review counts were taken from the listings on 19 October 2026.

  1. HSE isocyanates (retrieved 19 October 2026)
  2. Retained Regulation (EU) 2020/1149 (retrieved 19 October 2026)
  3. HSENI diisocyanates (retrieved 19 October 2026)
  4. Fire safety: Approved Document B (retrieved 19 October 2026)
  5. Hertfordshire Building Control PU-foam note (retrieved 19 October 2026)
  6. Soudal Soudafoam Gun Gap Filler (retrieved 19 October 2026)
  7. Soudal Soudafoam range (retrieved 19 October 2026)
  8. Penosil UK straw foams and gun foams (retrieved 19 October 2026)
  9. Polycell Expanding Foam (retrieved 19 October 2026)