You do not buy a second washer for foam. You buy soap that sits on the panel. On a Kärcher that is an FJ 10 C foam jet, about £30 to £33, clipped onto a K4. If you do not own a washer yet and foam is why you are shopping, the Nilfisk Core 140-8 Car Wash kit puts Super Foam in the carton. If you want soap without a second clip, the Bosch UniversalAquatak 135 already has a 450 ml bottle on the lance.
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There is no standalone foam-cannon shortlink on this site, so there is no FJ 10 C card. Buy the jet from Kärcher when you already own the gun. Do not pay extra for a Car & Home carton just to get a bottle you can add later. Wash order sits on the cars page.
What to buy
Best Kärcher path
Kärcher K4 Power Control Flex
£169
130 bar, 420 L/h, 8 m Flex hose. The washer most UK drives should start with. Add an FJ 10 C later. Do not buy a bigger K-class for foam.
Best foam in the box
Nilfisk Core 140-8 Car Wash
£189.99
Same 140-8 as the £189.99 standard box, plus a Super Foam sprayer and an underbody lance. Buy this kit if foam and winter arches are why you are shopping.
Best bottle-on-lance
Bosch UniversalAquatak 135
£114.98
135 bar, 7 m hose, 7.9 kg. A 450 ml detergent bottle already sits on the lance. The honest way to soap a car if you do not want a separate cannon.
Foam needs flow
| Path | How it soaps | Max pressure | Flow | Hose | Foam in the box? | Typical UK price (Aug 2026) |
|---|---|---|---|---|---|---|
| Kärcher K4 Power Control Flex | Add an FJ 10 C later. Plug ‘n’ Clean in the body is a thin shampoo | 20 to 130 bar | 420 L/h | 8 m PremiumFlex | No, on the bare Flex | £169. FJ 10 C about £30 to £33 extra |
| Nilfisk Core 140-8 Car Wash | Super Foam sprayer in the kit | 140 bar | 465 L/h max (348 L/h rated) | 8 m UltraFlex, internal reel | Yes | Car Wash kit costs more. The standard 140-8 is £189.99 without Super Foam |
| Bosch UniversalAquatak 135 | 450 ml high-pressure bottle on the lance | 135 bar | 410 to 450 L/h | 7 m PVC | Yes | £114.98 |
Prices checked August 2026. 360 L/h on a K2 feels thin on a dirty estate. 420 L/h is the comfortable rinse. A K5 is a 10 m hose and 500 L/h for a long drive, not a thicker blanket. That split is K4 vs K5. Petrol 200 bar-plus frames are the wrong tool for gloss paint.
Kärcher K4 Power Control Flex
- Buy: Check latest price £169Check latest price
- Pressure / flow: 20 to 130 bar, 420 L/h
- Hose: 8 m PremiumFlex
- Foam: none on the bare Flex. Add an FJ 10 C. Plug ‘n’ Clean is a thin shampoo through the body
Drop the Vario for paint. Open it for arches. The LED on the G 160 Q shows the step. That control is why a foam jet on a K4 beats a thicker foam on a machine you cannot turn down. Leave the dirt blaster on the hook when the car is out. B&Q has listed Car & Home at £259. Car & Home extras can push the live total higher. Useful if those extras are cheap in the bundle. Easy to overpay when the banner just says Home.
Skip it if you already own a Bosch or a Nilfisk and you only wanted a bottle. Stay in that clip. Skip it if there is no outdoor socket. A foam jet will not invent a 13A point. The rest of the yellow range is on the Kärcher hub.
Nilfisk Core 140-8 Car Wash
- Buy: Check latest price £189.99. Car Wash kit costs more · Nilfisk UK
- Pressure / flow: 140 bar, 465 L/h max, 348 L/h rated
- Hose: 8 m UltraFlex on an internal reel
- Car Wash kit adds: Super Foam sprayer and an underbody / arch lance
The Super Foam sprayer is the reason this kit sits on a foam page. It is not more bar. Pay the extra £54 when foam and arches are why you are shopping. Rated flow is 348 L/h, nearer a K2 than a K4. Buy it for the reel and the kit. Confirm the carton says 140-8, not leftover 140-6. Brand notes sit on the Nilfisk hub.
Bosch UniversalAquatak 135
- Buy: Check latest price £114.98 · Check latest price
- Pressure / flow: 135 bar, 7.5 L/min max (Bosch). Wickes quotes 410 L/h
- Hose / weight: 7 m PVC, 7.9 kg
- In the box: 3-in-1 nozzle and a 450 ml high-pressure detergent bottle
The bottle on the lance is the honest way to soap a car if you do not want a separate cannon. It will not throw the thick blanket an FJ 10 C throws. It will hold soap on the panel, which is the job. Fan jet for paint. Rotary for stone. The Bosch in full is the Bosch hub.
How to use a foam cannon
Soap is a low-pressure job. Apply, wait, then rinse on a wide fan. High-pressure soap wastes shampoo and sends foam into the drain.
- Pre-rinse on a wide fan, at a distance, from the bottom up.
- Apply car shampoo or snow foam. Do not let it dry. Work a side at a time.
- Mitt if the film is heavy. Two buckets if you use a mitt. The cannon does not replace that on a neglected car.
- Rinse on the same wide fan. Roof, glass, sides, then sills.
- Rinse the bottle and the lance after, or the next rinse still spits soap.
Kärcher wants a flat jet, at least 15 cm from paint and 30 cm from tyres. Further is safer on old lacquer, wraps, chrome and cameras. Patio detergent is not a foam fill. Washing-up liquid strips wax. If the only path for the water is a road gully, skip the soap or take the car to a wash that already treats the water. First-use sits on how to use a pressure washer.
FAQ
What is the best foam cannon for a pressure washer in the UK?
On a Kärcher, an FJ 10 C on a K4 Power Control Flex. If you do not own a washer yet and foam is the point, the Nilfisk Car Wash kit. If you want soap without a second accessory, the Bosch already has the bottle.
Do I need a foam cannon?
You need soap that stays on the panel. An FJ 10 C, Nilfisk Super Foam or Bosch’s 450 ml bottle all do that. Plug ‘n’ Clean is thinner, still better than a dry blast.
Will a foam cannon work on a Kärcher K2?
Yes, if the jet fits and you stay on the wide Vario. The rinse is slow and the hose is short. Do not buy a K2 because this page mentioned foam.
K4 or K5 for foam?
K4. Foam does not need 145 bar. The K5 earns its keep on a long drive.
Does a Bosch need a separate foam cannon?
No. The UniversalAquatak 135 already has a 450 ml bottle on the lance.