Print this handy guide or even laminate it to keep on site to make sure you are never left wondering what you’re doing when using concrete mixers again. This guide will explain some of the most asked questions about concrete mixers and why you might be having them as well as an easy to understand answer to help you move forward in all of your DIY conquests. Whether you’re a seasoned mortar man or a complete concrete newbie just trying out some long-lasting crafts, there’s some useful information for anyone below.
What Are the Different Types of Concrete Mixers?
The basic definition of a concrete mixer is something that will mix up your cement, water and other aggregates to produce concrete. They can be powered by petrol put directly into the machine or they can be electric and will need a source of power like a wall outlet or a portable generator. Electric concrete mixers are usually smaller, cheaper and require less maintenance and are best for small projects whereas petrol powered mixers are better suited for the outdoors, rough terrain and large pours on construction sites.
You can then get two more variations between concrete mixers, a drum type versus a pan. A pan type mixer has blades that move around the inside of the machine and will mix the ingredients together and release the concrete from a hole in the middle, these types of mixers are very efficient. Drum mixers are more widely known and are shaped like a cone that will constantly spin to mix the ingredients together.
There are two types of drum mixers and they each work a bit differently, the first type is a tilting mixer which will release the finished concrete by simply being tilted over when it has spun for a sufficient amount of time. This can be used for large pours where you simply need to create a large amount of batches in a short amount of time. Unfortunately due to it relying on gravity to release the concrete, it can start to build up at the bottom of the drum if it is not inspected frequently.
The second type is non-tilting and will instead only spin horizontally. It has two openings and the aggregates are fed inside one end, mixed up by the blades within the rotating drum and the finished concrete will then be pulled into a chute that is slightly inclined. These machines work slower and are better suited for smaller projects as the delay in a large pour will mean some of the concrete will begin to dry and cure before the rest does.
Is it Cheaper To Mix My Own Concrete?
Like eating food in a restaurant or paying someone else to handle your taxes, mixing concrete will always be cheaper if you take on the burdens yourself rather than outsourcing. Buying aggregates separately and mixing on-site will definitely be cheaper than buying pre-mixed batches for delivery in a truck. Having a concrete mixer yourself will further decrease the manpower needed and begin paying for itself in the long-term.
The initial capital you need to invest will always seem daunting at the time, but relying on yourself will always mean there are less points of failure in an operation. Like your taxes and an accountant however, sometimes it is best to get someone with experience or skills that you don’t possess the first few times you attempt a project to make sure you’re doing things correctly. You will need to have seen properly combined concrete before and understand how it is mixed in order to spot unmixed concrete that will need to stay spinning in the drum for a bit longer.
Why Do Concrete Mixers Turn?
There are two reasons why concrete mixers turn, the machines on a construction site will obviously be to mix up the dry ingredients with water for the first time. A truck that you see drive passed that has a constantly turning drum will not only be pre-mixing aggregates that may not be fully combined at the factory, but the constant spinning will also help prevent the concrete from beginning its chemical reaction to start curing. This does not mean you should ever use your mixers to store concrete as it will still harden and a constantly spinning motor will not last for very long.
Is It Worth Buying a Concrete Mixer?
The simple answer to this question is yes! Although it truly depends on the specific needs of your construction site. If you own a construction business or are regularly completing building projects, then it may become unnecessarily expensive to hire concrete mixers each and every time.
You can consider concrete mixers as an investment, and the product could actually end up saving you money. Using concrete mixers will enable you to mix large batches of concrete at one time, much more efficiently than mixing by hand, which means your employees will be less fatigued and you can complete more projects at a faster rate.
Even if you find yourself with less construction projects you can still find ways to make your concrete mixers work in your favour. Concrete mixers can be used at home for numerous craft projects and quick fixes around the house or driveway. They can also be rented out to other construction companies to create a source of revenue in the meantime, just be sure that the company you rent it to will treat it with the same care and attention that you would.
How Long Does It Take To Mix In A Machine
This can depend on the size of your machines, the strength of the motor and the amount of aggregates you are actually placing within it, but an average time you would be looking at per batch of concrete is 3 to 5 minutes. This is obviously much faster and less strenuous than doing it by hand which depending on the manpower available can take well over 10 minutes for a single batch. A machine’s efficiency can always change over time depending on the level of maintenance and overall care as old concrete stuck inside the drum can begin to slow the spin down and lengthen the amount of time needed per batch.
How Do I Remove Hardened Concrete From My Mixer?
No matter how vigilant you are, concrete will inevitably begin to form small clumps within your drum and start to harden along the walls, this will make everything heavier and work your motor harder. The concrete will also continue to build up and take up most of your mixing volume before long if it isn’t removed. Before it can get out of hand, you should begin by filling your mixer’s drum with water and some gravel.
Let the machine spin with this mixture inside and begin to gently beat the outside of the drum with a rubber mallet. This will agitate any large clumps of concrete that are loose and mix them into the spinning water. Make sure you don’t dent the drum with the mallet.
Drain out the water, gravel and large concrete chunks that have come loose. You will then need a small hammer and chisel to get any more stubborn pieces sitting at the bottom of the drum, usually around the curves. The final step is to get a chemical from your local hardware store that will eat away at the final layer of concrete without damaging your mixer, be very careful with your ratios here.
What Should I look For When Buying a Concrete Mixer
What types of work will you be using it for and how often will you be using it? If you are working on a construction site and are constantly mixing by hand it will be worth looking into a petrol powered machine that tilts so you can make a large amount of batches without it starting to dry. If you are going to use it a few times a month and at home you should look into a small electric machine, possibly a non-tilting machine to get a better consistency in your pours.
Once you have decided on what powers your machine and the way it likes to spin, next you need to look at the different drum sizes available. You need to really think hard about how much concrete you really need to make at a time as you won’t always need the biggest size available. You should also not go too small and remember that the total volume of the drum is not how much concrete you can actually mix inside at a time as you will always need to leave some space at the top.
Next you need to compare the motor performance of the various machines you are looking at. The stronger motors will mix the aggregates together faster and more efficiently than a slower motor. A slower motor will also be more prone to concrete drying within its drum due to it sticking in one spot for too long.
Next you should look at how easy it will be to maneuver your concrete mixer in and out of your construction site or home depending on the situation. If it is for a construction site it will need rugged wheels that can handle the rough terrain and easily be moved around the site to the best position for a pour. A machine used mainly at home will not need to be moved around as much and some machines can even be attached to a trailer.
Is It Okay If It Rains After a Pour?
This depends on a number of factors such as how fresh the pour is and how far along it is in the curing process, how strong the rain is falling and how large the droplets are and if there are strong winds that can cause any other debris to blow across the surface. If your concrete is far into the curing process, such as after 5 days, and the rain droplets are small this can actually help keep your concrete moist while it cures and you will no longer need to hose it down. If the concrete is freshly poured however, even small raindrops can begin to leave small indentations or being to actually mix with the concrete causing it to not cure at all.
If it is raining it is always best to delay a concrete pour so that there is no excess water to throw off your aggregate calculations. If you have no choice but to go ahead with the pour, you should try to create some sort of temporary structure during the pour and definitely cover the concrete with a tarpaulin when you are done to give it time to dry. It is always better to wait for dry weather to help the water evaporate and create a stronger overall structure.