Maintenance Tips for Gunite/Dry-mix Equipment

A little planning and precaution always goes a long way in the success of a project and the life of your equipment.

For any given job, a gunite contractor and its crew will have, as a very minimum, to operate and maintain a gunite machine, a material nozzle and hose, water hose, air compressor and an air hose.

Lubrication is an essential part of maintenance

A good part of maintenance on new and used machines will involve regularly oiling various part of your equipment and replacing certain parts over time. That’s just the reality of operating heavy equipment! Another good thing to remember is that every part of the machine that touches material flowing through it will wear out the fastest. So let’s see what some of these are.

If you have a bowl-type gunite machine, you will eventually have to replace the wear plate, the wear pad and material outlet. But before you get to that point, you will need to oil the pockets of the bowl after having cleaned it first after each job so that you don’t get material accumulation. If you have a steel bowl, you will need to use a hammer and something like a chisel to dislodge dried leftover material. If you have a steel/poly bowl, flip it on its belly and pound it  all over using a rubber mallet then chip any small pieces left, after every job.

Over time, the wear plate will also start to degrade. How can you tell?  Grooves will be showing up on the plate and/or in the pocket surfaces which can affect the rotation of the plate. When this happens, you should have a company resurface the plate.

Another part that will also show sign of deterioration is the wear pad due to its contact with the material. Don’t wait to replace it because it will cause faster wearing out of the wear plate if left damaged. It will also affect the quality of the air flow into the system.

DON’T: Tighten the hold clamp to try to extend the life of the wear!
DO:  Replace the wear pad as soon as it shows signs of slight deterioration.

There is also a piece of felt that protects the wear plate from the bottom of the hopper that should be lubricated until it becomes flexible and seal. No need to take anything apart to reach the felt, just use the holes in the hopper to do the lubricating. Having well oiled seals will prevent dust from escaping and create a safer work environment for your crew.

DON’T: Ignore an accumulation of dust next to your gunite machine. This is a sign that something is not working properly and needs to be checked.
DO: Replace the felt piece with a new one.

What about the air motor? The air lines comes with a filter and lubricator. Without the filter, the air that goes into the motor wouldn’t be clean and the lubricator puts a small amount of oil into the air. Both are required for the motor to function properly. As with all filters, you will need to check it to see whether or not they need to be replaced. Make sure to regularly inspect and adjust the oil level of the air lubricator.

Most gunite machines are connected to a gear box which will also need to be oiled. Some models come with an exhaust chamber that needs to be emptied out on a daily basis. The idea is to remove anything that could end up in the hopper base and could prevent rotation in the feed bowl.

DON’T: ever reach inside the hopper with your hands or arms while the air line is connected because the agitator could be moving.

DO: Connect an extra exhaust hose to the machine to bring down even more the level of dust on the job site.


What about hose accessories and nozzle maintenance?
The one more important piece to take care of in a nozzle is the water ring, usually made of brass or aluminum. You must inspect the tiny holes in the ring before starting any job and make sure there is nothing clogging them from a previous job. When cleaning the holes is no longer possible it is time to replace the ring.

DO: coat the water ring with some oil for extra protection
DON’T: ever drill holes in the water ring if the original holes are no longer working.

To eliminate any potential defects which cannot be seen by visual examination or in order to determine certain characteristics of the hose while it is under internal pressure, we suggest you conduct non-Destructive Hose Pressure Tests

Airplaco PG25 Gunite Machine

If you are looking for a  great gunite machine for your next job, give us a call at 503-281-2105 and we can help you find a perfect fit.