"1 bag concrete mixer" is how many builders, dealers and rental shops describe the size of a drum mixer: a machine that mixes one 50 kg bag of cement, with the sand, stone and water that go with it, in a single batch. It is the most common mixer size on small and medium building sites, and for good reason.
What "1 bag" means in practice
Concrete is usually measured on site by volume ratios of cement : sand : stone. A common general-purpose mix is 1:2:4. As a rule of thumb, a cubic metre of 1:2:4 concrete needs roughly 6.2 to 6.5 bags of 50 kg cement, so one bag makes about 0.15–0.16 m³ of concrete.
A one-bag mixer therefore has to turn over roughly 150–170 litres of wet concrete per batch with room to spare, because a drum is never filled to its nominal volume. The usable batch of a drum mixer is about 60–65% of the drum capacity.
Why 350 L is the classic one-bag size
A 350 L drum gives about 200–220 L of mixed concrete per batch, which covers a one-bag batch comfortably, including richer mixes that produce more volume per bag. That is why our 350 L and 385 L concrete mixers are sold as one-bag mixers.
- 250 L — less than one full bag per batch. Good for repairs, small houses and tight sites.
- 350 L / 385 L — the one-bag workhorse for houses, small buildings, footings and slabs.
- 420–500 L — more than one bag per batch for larger jobs and higher daily output.
The exact batch always depends on your mix design, so treat these figures as a guide, not a specification.
Choosing a 1 bag mixer
Wheels and tyres. Two-wheel models with large pneumatic 5.00-12 tyres tow and move easily on rough ground. Four-wheel models stand more steadily on uneven sites. Solid 4.00-8 tyres never go flat, which matters where tyre repair is hard to find.
Engine. Choose by what is available on site:
- Electric (2.2–5.5 kW, 220 V) — quiet and cheap to run where there is reliable power.
- Gasoline (GP160 / GP200) — light and easy to start, the usual choice for mobile work.
- Diesel — for remote sites and long working days.
Drum steel. Our 350 L drums use 2 mm steel for the upper drum and 2.5 mm for the lower drum, and the 385 L uses 2.5 mm and 3 mm. Thicker steel can be specified for heavy daily use.
Getting the most out of each batch
- Add about half of the water first, then the stone, the sand and the cement, then the rest of the water.
- Do not overload the drum: a one-bag mixer is sized for one bag, and overfilling spills material and strains the drive.
- Mix until the colour is even, and keep the mixing time the same for every batch.
- Wash the drum out at the end of every day before concrete sets on the blades.
Buying 1 bag concrete mixers from Vietnam
Phu Long builds 350 L and 385 L one-bag concrete mixers, also called cement mixers, in our factory in Ninh Binh, Vietnam, along with 250 L and 420–500 L models. Every mixer can be built with the engine, tyres, colour and logo your market needs, and several models can share one container.
Tell us your market, quantity and destination port on WhatsApp at +84 946 964 669 or through our quote form, and we will recommend the right one-bag model and send an FOB or CIF quote.
