The right mixer for the job
Mixers, pumps and delivery systems
By Joe Kehoe
Say the words “mortar mixer,” and an image pops into your mind immediately. Specific details may differ person to person, but the overall image would look basically the same. The basic components would be a drum, a shaft with paddles attached, and a drive system to make it work.
The specific features, options and variations of how these components come together are the manufacturer’s preferences. These differences give us various sizes, colors, drive systems, material thicknesses, prices and all the other features and benefits that mixer manufacturers build into their brands. The key is determining which mixer is right for your job.
What you may not knowAt this point, you may be wondering what you could possibly learn about mortar mixers that you don’t already know. Keep reading.
Records of mortar mixers date back to 8th Century AD. The 8th-Century mortar mixer was a round pit in the ground with a large, central post. The post in the middle served as a spindle for a revolving rake with two or four arms stretching out beyond the pit. The arms stretching out beyond the pit could then be turned by man or animal power.
Although not portable, you put this together, and you have a mortar mixer. The men who built these original mortar mixers must have believed it was the best tool ever, and that their mixer was better than any other mixer or method out there. They probably even figured it is was the perfect size, and that donkey power was better than camel power. Though mixer construction has changed for the better since the 8th Century, one thing hasn’t changed: Everyone thinks his way is the best way. Perhaps, sometimes, we all need to take a fresh look at an old problem.
Most contractors reading this will have a “your brand” mentality. They know all about their mixers. If you are blessed to have your own in-house maintenance crew, then you know your brand, inside and out. If you don’t have your own in-house mechanic you, will need to take your mixer to a local repair shop to get it fixed. The relationship with your local shop for sales, service and parts should not be underestimated. Keep in mind they know about “your brand,” and they know about all the other brands, too. This will help when you need to get something fixed on your mixer as well as when the time comes to replace or upgrade. A trusted source of information can keep you from making a costly mistake on something that is not right for your company.
I have been selling and servicing mortar mixers for 14 years, having sold several million dollars’ worth of mortar mixers. To keep these mixers running throughout the years, I have ordered and sold hundreds of thousands of dollars in parts for all mixer makes and models. I have seen new mixers – all bright and shiny – going out the front door, and literally falling apart while being dropped off in the back.
Once, a customer towed a mixer into our yard for repair and, when the contractor put his truck in park, the mixer frame broke in half, leaving only the tow pole and front post attached to the truck. That guy purchased a new mixer, by the way. Every now and then I have to scratch my head and wonder how that happened. But, I know in what kind of work environment these mixers are must perform. I understand that this is construction, and – more exactly – masonry construction.
Mason contractors ask a lot from their equipment. The environment is harsh, and the workers are harsh on the equipment. This is all the more reason to make a careful selection. As mixer manufacturers bring new products and designs to market, you should rely on your local sales and service shop to help keep you informed.
Mixing and matchingThe conventional wisdom for most contractors is to buy into one particular mixer and buy a fleet of that brand. I have heard and understand the reasons why: “They will all operate the same,” or, “If something happens to one, I can take parts off the one that the forklift ran over last month,” or lastly, “I don’t want to have to worry about where the big mixer is.”
All valid points, but just as you probably don’t have one style of trailer, one type of truck, or one size wrench in your toolbox, having one mixer style or size is limiting. Mixer size should be based on the number of masons you are trying to supply. The mixer’s drive system should be based on what you will be mixing. For instance, will you be mixing grout as well as mortar?
One of the most important features on a mortar mixer is the drive system. Through the years, only a few changes to the typical drive systems have occurred. Three basic types of drive systems exist: belt drive, enclosed gear drive and hydraulic.
Belt driveThe belt drive is the most common type, due to the popular size range of six- to nine-cubic-foot capacity and the lower overall pricing. Mortar mixer sizes in the belt drive configuration range from two to nine cubic feet. The typical setup starts with either a gas engine or electric motor, connected by belts that drive a pinion gear to a large bull gear to drive the paddle shaft. Several manufacturers of late have omitted the gears in favor of a series 80 chain-and-sprocket configuration.
Enclosed Gear DriveThis comes in two forms. Direct drive, with a typical size of 12 cubic feet, is used frequently on tag unit pumps for plastering. The next configuration is the belt-to-enclosed gear drive. This hybrid is a good mix of the benefits of the gear drive and the cost savings on a belt drive unit. Typical sizes range from six to 12 cubic feet.
HydraulicThis drive system once was owned only by the larger contractor with large commercial jobs. Now, several manufacturers are developing smaller, less expensive hydraulic mixers, making the benefits of hydraulic drive system more available to all contractors. You can get them in nine- to 20-cubic-foot sizes. They do have a higher initial cost of ownership, but the mixer is practically maintenance free. You save on the back end and have less down time by not having to change belts, gears, chains and bearings. Fluid moves in the system and generates almost no wear. You also can mix grout, mortar and even the occasional bag of Sakrete. Hydraulic-driven mortar mixers are strong enough to turn the toughest of mixes, and, if the paddles get jammed, you can reverse the paddles to clear it out. When purchasing a larger hydraulic mixer, you may want to consider one with a hydraulic drum dump to save your laborer’s time and back.
So, which mixer is best for your job? Let the job dictate. Manufacturers can incorporate all kinds of features for durability and longevity. However, one of the best assets any mixer owner has is an operator who will take a few minutes every day to check the fluid levels, check the cleanliness of the air filter, and grease the fittings on the machine. One of the most important things on the checklist is to keep the mixer clean.
No matter what the size, drive system or use during the day, one should wash down the machine to eliminate the residual sand and mortar that, if left in place, will shorten the life of the machine. Selecting the right mixer for your job is paramount. Assuring that your employees know how to effectively operate, service and maintain your mortar mixer will keep your masons on the wall.
Originally published in Masonry magazine.
About the Author
Joe Kehoe works for Georgia-based Trowel Trades Inc. He specializes in all types of masonry tools and equipment and can be reached at 770-271-8825 or firstname.lastname@example.org. Visit www.troweltrades.net for more information.