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Air sander compressor size

Updated: 21 October 2026

The pad slows after about a minute, the tank gauge still shows pressure, and the sander you just bought is being blamed for a compressor that cannot keep up. Air sander compressor size is a free-air question, not a tank-litre question. This page stays on air supply. The listings themselves are on the [air sander comparison](/hub/sanders/air-sander). Figures below come from maker pages, Air Supply's guide, and amazon.co.uk reviews checked on 19 October 2026. Products Compared did not measure these compressors. A qualifying purchase can earn a commission at no extra cost to you.

The pad slows after about a minute, the tank gauge still shows pressure, and the sander you just bought is being blamed for a compressor that cannot keep up.

Our top picks

Draper Draper Storm Force 150 mm

Best overall

Draper Draper Storm Force 150 mm
9.1/10about £51.35
View offer
SPTA SPTA mini air sander set

Best value

SPTA SPTA mini air sander set
8.4/10about £25.20
View offer
Festool Festool LEX 3 77/2,5

Rank 3

Festool Festool LEX 3 77/2,5
6.6/10about £526.97
View offer
On this page
  1. 1.Tank litres are storage, not flow
  2. 2.Match the tool's air figure, then add spare
  3. 3.Hose, regulator and water
  4. 4.What this set does not tell you

Tank litres are storage, not flow

A 50 litre tank and a 100 litre tank tell you how much air is stored when the pump stops, not how much the pump can replace while the pad is turning. A full tank can carry the first thirty to ninety seconds. After that, speed falls to whatever the pump can sustain. A RUNQIN 125 mm ran out of air after about a minute and a half. A Draper on a 5 cfm compressor at 90 psi held speed for two or three minutes. The gauge can still sit above zero. Write down free-air delivery at about 6 bar before the tank size. Which pad you then fit is on the 125 mm or 150 mm air sander page.

Match the tool's air figure, then add spare

Treat a published figure as a claim and add spare capacity. Air Supply's rule of thumb is the tool's SCFM multiplied by 1.2, and that page puts many orbital sanders near 7.2 CFM. That is a class rule, not a measurement of these twelve listings. Draper states about 3 cfm, roughly 85 to 87 litres per minute, and a UK review says a 5 cfm compressor did not hold the 65084. The RUNQIN bullet claims 8 cfm. Festool states 270 litres per minute at 6 bar and asks for at least 350 litres per minute. SPTA's mini-kit reviews say use is high, including on a compressor around 9 cfm. A different SPTA set has a UK review at about 4 CFM. The Anesty 150 mm, both large Proster palm tools, the LithiCraft and the Enwye belt publish no CFM line. Do not invent one from the price.
Draper Draper Storm Force 150 mm

Testsieger

Draper Draper Storm Force 150 mm
9.1/10about £51.35
View offer

Hose, regulator and water

Draper specifies at least 3/8 inch, about 10 mm, on a 1/4 inch BSP inlet, and a larger bore past about 25 feet. Festool wants at least 9 mm inside an IAS 2 or IAS 3 hose. A leak is lost flow. Seal it, and do not hide it by raising the regulator. Drain the tank and fit a water trap. Draper asks for a filter-regulator-lubricator. Festool expects lubricated air. The caps are 6.3 bar on the Draper 65084 and 6.2 bar at the Festool inlet. The running sequence is how to use an air sander.

What this set does not tell you

Most of these ASINs have no CFM field. Use the maker figure where it exists, treat a bullet as a claim, and keep spare capacity. Printed CFM can be optimistic. Tank litres will not save a slow pad after the first minute. If employees use a qualifying pressure system, the Pressure Systems Safety Regulations 2000 require a written scheme of examination. Once the flow holds, the price bands are on the best air sander page.

Common questions

Is a 50 litre tank enough?
Only if the pump's free-air delivery covers the sander with spare capacity. The litres are storage. If the pad dies after a minute, the next check is CFM at about 6 bar, not a larger tank with the same pump.
What is CFM?
CFM is cubic feet per minute, a flow rate. Draper's about 3 cfm is roughly 85 to 87 litres per minute. Festool's 270 litres per minute is consumption at 6 bar, and 350 litres per minute is the compressor minimum. Compare the numbers at a similar pressure.
Why does the sander die while the tank still has pressure?
The tank has some air left, and the pump cannot replace what the sander is using, so pad speed falls. Pressure on the gauge is not flow at the pad. A larger tank delays the moment. It does not raise the sustained speed.
Can I trust a 3 cfm or 4 cfm claim?
Treat it as a claim and look for a review on a named compressor. A 4 CFM comment on one SPTA set does not describe the other SPTA set, whose reviews say use is higher. Add spare capacity on top of any figure you do trust.
What hose size should I use?
Use at least 3/8 inch, about 10 mm, for the Draper, and go up a bore on a long run. Festool wants at least 9 mm inside an IAS 2 or IAS 3 hose. A thin hose over a long garage run will make a capable compressor look too small.
Do I need a regulator and a water trap?
Yes. Drain the tank, trap the water, and set the regulator to the tool's stated maximum. Oil the air only when that tool's manual asks for lubricated air. Raising the pressure to mask a leak or a slow pad is outside those caps.
When is compressor choice a work-equipment question?
It becomes a work question when employees use the system. Qualifying compressed-air systems need a written scheme under the pressure-systems regulations. A home user still needs a safe hose, a drain and a regulator. Stop if the hose is split or the pad will not turn.

Related pages

Air sander buying guide

Air sander

125 mm or 150 mm air sander: which pad fits the job

Best air sander 2026: Draper top pick, SPTA mini kit

How to use an air sander: set pressure, hose and dust

Sources

Sources taken from the research digest. Prices, stars and review counts are the stored amazon.co.uk listing figures.

  1. HSE — wood dust (retrieved 21.10.2026)
  2. HSE WIS23 — wood dust (retrieved 21.10.2026)
  3. HSE HSG39 — compressed air safety (retrieved 21.10.2026)
  4. HSE — noise for employers (retrieved 21.10.2026)
  5. HSE — hand-arm vibration (retrieved 21.10.2026)
  6. Draper 65084 air sander (retrieved 21.10.2026)
  7. Festool UK LEX 3 77/2,5 (retrieved 21.10.2026)
  8. Air Supply — compressor size (retrieved 21.10.2026)