Diamond Concrete Grinders, Polishers & Accessories
The Satellite series of Concrete Grinders range from the single 10” head “Meteor” through to the large 3 phase Satellite 760 - 12. The most popular of the Satellite range is the Satellite 480/550 which is available in either single phase, three phase or petrol motors. It is an all-rounder that will grind concrete as well as polish to the highest of shines. It is Ideal for small to medium projects that don’t have access to three phase power. Fits through standard doorways and is manageable by one person. The largest of the range is the Satellite 760-12 for large commercial areas with production rates being between 200-275m2 per hour. All Satellite Concrete Grinders are Australian made and built to last.
Hand Held Concrete Diamond Grinder
Hand held 5" & 7" surface diamond concrete grinders with convertible shroud. It is Ideal for concrete diamond grinding right up to the walls and cleaning up those hard to reach areas that the larger machines can't get into. It attaches to a separate vacuum for dustless concrete grinding.
Meteor 250 Concrete Grinder
The Meteor 250mm concrete diamond grinder is ideal for those smaller areas that you can’t get a larger machine into. It has no belts or pulleys, making all of the power available to the disc and allowing grinding to within 20mm of walls. Ideal for glue removal, levelling of high spots and even for producing polished concrete. The Meteor 250 is a great machine for floor preparation and polishing in domestic projects and those “hard to get to” areas in large commercial projects. Compact and easy to store with a fold down handle. The Meteor is available in a single phase or petrol motor.
Satellite 480/550 Concrete Grinder
The Satellite 480/550 Concrete Diamond Grinder is extremely robust, reliable and virtually indestructible. It is available in either single phase, three phase or a petrol motor with a 5 year warranty on the cyclo transmission. It has a three head disc drive that is ideal for grinding, polishing, levelling, cleaning, glue removal and re-surfacing. The Satellite 480/550 is very easy to repair, has non marking wheels and a handle that can be adjusted for compact storage. The ideal Concrete Grinder for small to medium projects.
Satellite 760-6 Concrete Grinder
The Satellite 760-6 is a 2 head, 6 disc, extremely robust, reliable, virtually indestructible, heavy duty concrete diamond grinder and polisher. It has two 4.0 kw three phase motors with a 5 year warranty on the cyclo transmission. It has a six head disc drive that is ideal for grinding, polishing, levelling, cleaning, glue removal and re-surfacing. The perfect combination of power to weight ratio makes the 760 an effortless and easy grinder to operate. Available with Variable speed and can fit through most standard doorways. The Satellite 760-6 has an approx production of 110 – 150m2 per hour.
Satellite 760-12 Concrete Grinder
The Satellite 760-12 is a 4 head, 12 disc, extremely robust, reliable, virtually indestructible, heavy duty concrete diamond grinder and polisher. It has four 4.0 kw three phase motors with a 5 year warranty on the cyclo transmission. It has a four head, 12 disc drive that is ideal for grinding, polishing, levelling, cleaning, glue removal and re-surfacing. The perfect combination of power to weight ratio makes the 760 an effortless and easy grinder to operate. The 760-12 is available with variable speed and compact enough to access most areas. With production rates at approx 200 – 250m2 per hour, the largest of the Satellite rang is ideal for large commercial / industrial projects.
"CONCRETE DIAMOND CUP WHEELS & PLUGS"
ACCESSORIES
"Super Sander"
The "Super Sander" is a 4 x 5" diamond wheel, freely rotating head attached to a solid plate. Ideal for removing paint, plaster and a variety of adhesives from concrete slabs. Attaches quicly and easily to a Polivac sander for effortless grinding. A sturdy steel construction that saves time, money and labour fatigue.
Nilfisk Twin Motor Dust Extractor
The Nilfisk twin motor 50ltr Dust Extractor is a high performance industrial vacuum capable of handling the toughest of clean ups and grinding residue. It's edge over it's competitors is it's specially designed emptying system that allows for safe and easy disposal of materials. An ideal dust extraction for the meteor 250, satellite 480/550 and hand grinders.
Nilfisk 1460 Dust Extracor
For heavy duty industrial cleaning and dust collection.
The tougher the cleaning, the better the vacuum cleaner needs to be. This is why so much thought has gone into the design of the 1460. With 3600 litres per minute of air volume, and 1500 W of maximum power, it is capable of fast, productive cleaning of dirt, metal chips and liquid spills
Supa Dust Separator
The supa dust separator is placed in-line between any concrete grinder, cutting tool or dust collector. It collects 93% of dust before reaching the vacuum unit, increasing working efficiency and life expectancy. Easy to empty, reduces filter blockages and increases the life of the vacuum. A rugged poly construction with hard wearing rubber castors.
Easy Hammer
The versatile EASY HAMMER packs a punch, saving you a lot of hard work and effort. Let the EASY HAMMER take the workload off your back! No more struggling or bending trying to handle heavy hammers, the Easy Hammer takes the pain out of demolition and renovation. Easy Hammer lifts all types of lino and tiles, breaks rocks and blocks, cracks concrete and sandstone all with a minimum of effort. With a wide range of angle the Easy Hammer adapts to any situation with maximum leverage.
"Hoverhood" Dustless Shroud
The Australian made “Hoverhood” is recognized as the best dust shroud available. A extremely strong construction, edging section and removable edging cover. No other shroud has the same combination of features including the strong and very simple mounting collar inserts. Built strong from steel so it will not warp or twist in the sun. Comes with exact-fitting inserts for each concrete grinder brand it always locks on tightly to the angle grinder with no movement. The air flows under the seal where the dust is generated giving it superior dust pick up.
"Information on Concrete Grinding"
Your cup wheel diamond segment bond needs to match the concrete hardness.
The confusing thing is that soft bonds are for hard concrete and hard bonds are for soft concrete.
Sounds crazy, but this is the explanation...
The diamonds only cut well if they are exposed.
The diamonds are embedded in a molten metal called the bond (or matrix) and allowed to cool.
The final product is called a segment or diamond block and can be made in a variety of sizes and shapes then silver soldered or welded onto a plate, or cup wheel, or cutting blade for final use.
The size of the diamonds can vary and so can the wear of the metal bond around them.
Here's what happens...
As you grind concrete the diamonds cut into it and scratch it away. During this process the diamonds break and wear down, but at the same time the bond metal is worn away by the sands of the concrete which allows more diamond to be exposed so that cutting can continue. When you grind concrete that is too hard for the bond (matrix) the diamonds blunt and break, but the hard matrix is not worn away so the new diamonds are not exposed, then the cup wheel stops working. The diamond block is then flattened, polished and gets very hot.
At this stage you need to press harder and stay in the same spot longer until your temper starts to rival the heat of the diamonds.
Grinding hard concrete:
To grind hard concrete use a soft bond cup wheel with larger diamonds around 20 grit size. When that fails to work a trick that often does the job is to wet the floor and allow the water to soak into the concrete, then grind again. The grinding dust will be moist and more abrasive which will open up the diamonds in the matrix again. This may have to be repeated for each pass.
Sands and bonds are the key elements. The sands produced by grinding the concrete wear away the surface of the bond which keeps the diamonds exposed. If there is too little sand or the bond is too hard for the hardness of the concrete, the diamonds will not continue to be exposed and will stop cutting. So for hard concrete you need a softer bond so that it wears away a little and for very hard concrete you need a softer, softer bond.
What about soft concrete?
Just the opposite. You need a hard bond for soft concrete because it produces plenty of sands and they can wear the bond very quickly.
What makes concrete hard to grind? This is the million dollar question.
Two main things contribute to concrete hardness - the ratio of cement & water in the mix and the type of aggregate used. We will not get technical here and talk about size of aggregate, slump, water retention, curing and all that other stuff. Hard concrete means a hard paste (the grey matter that we recognize as concrete). Hard aggregate means the hardness of the stones used in the concrete mix and there are very hard ones and quite soft ones used depending on the local supply.
Grinding aggregate:
The unexpected variation comes when you have medium strength concrete (with very hard aggregate)
which you grind easily at first, but as you get into the aggregate your speed slows down dramatically
because there is possibly only 15% concrete paste now and 85% aggregate which is harder than the concrete. So then you may have to change to a softer bond (cup wheel) than the one you started with.
Diamond size:
Generally speaking you use a larger diamond grit (low number) for faster removal of concrete and for harder concrete. Because larger diamond grits are more aggressive they are not as smooth to grind with which you will notice at 30/40 grit and below.
Polished concrete:
To polish concrete you start with a coarse diamond and approximately double the grit number (halve the diamond size) with each new pass until the floor is polished.
For example, with a satellite concrete grinder use 30/40+40/50 Coarse for first cut, change to 100/80 Fine for second cut, then 200 Very Fine for the final cut as your metal bond grinding preparation before polishing. The concrete will not be polished but it will be very smooth, ready for resin bond pads to complete the polishing work using low speed hand grinders.
Note that a 9 in (230mm) angle grinder runs too fast for resin pads and grits above 80 mesh will quickly heat up the segments if the concrete is medium to hard strength. You then need to use a slow speed grinder or grind it wet.
Polished concrete look using a clear polyurethane - Tuff Coat Concrete:
After using the very fine cup wheel you can get a polished concrete look by applying a couple of coats of Tuff Coat Concrete without the need to actually polish the surface.
Avoiding Concrete Grinder Burnout
If you are using an angle grinder on difficult, sticky floors and it is slowing down so much that you smell the motor burning do not stop the grinder or it will burn out! The motors are very powerful , but they generate a lot of heat. They have a strong fan inside that sucks air in around the back handle and blows it out the front of the grinder to keep the motor cool.
Do this instead..
If it smells like it is too hot, immediately lift the grinder off the floor or move it to an area where it can spin freely again which will allow the fan to pass cool air through the grinder and cool it down. This will only take about 20 seconds. Angle grinders are OK used to their capacity which naturally slows them down a bit, but try not to slow them too much.
What slowing the grinder does:
On very sticky materials the friction from the disc melting the product on the floor can cause the grinder to work so hard that it slows down to half its speed. The extra load pulls more current through the windings and causes them to heat up and it slows down the fan that is meant to keep them cool.
Result - a double whammy of heat! ... but still some cooling.
Stopping the grinder at that time removes all cooling so that the temperature rises and ruins the motor wiring. Result - new grinder.
Grinders can take a lot of punishment. Experience has shown that grinders can get very hot many times without problems if they are cooled again quickly in the manner described above.
But why work on the edge of disaster? If the grinder is slowing down strongly on sticky material just take smaller bites into the coating.
No other grinder using the same power source will do it faster so it is just going to take longer and that type of grinding situation is not very common, it only happens to some contractors very occasionally.
PCD Scraper Discs can stop the slowdown:
If it is a more frequent occurrence there may be a better way to tackle it which is with a PCD scraper disc fitted to the angle grinder instead of the diamond grinding cupwheel. The coating or glue is scraped away instead of being ground. They can be very fast and will tackle coatings of 500 to 10,000 microns thick.
Maintenance of your angle grinder:
Some periodic maintenance is require although you will be surprised at just how long it can keep working without any. The difficult part is explaining how long it will take to wear.
A guess would be maintenance once per year when it is used three or four times a week for 2 hrs each time.
There are only two things to keep an eye on:
First is the brushes. They wear very slowly, even in a concrete dust environment and you can check them by first disconnecting the power.
Next remove the small panel at each side of the grinder near the trigger-switch handle and remove the carbon brushes that are connected to a spring. Check your grinder manual for more information.
The second thing to check is wear of the front bearing. They both seem to wear at about the same time so if you replace one, also do the other.
To check bearing wear, disconnect the power, turn the grinder over and try to wobble the diamond disc on the shaft. There is no wobble on a new grinder.
If you can feel a definite wobble take it to a power tool shop and have the bearing replaced. If you let it go for too long the gears will wear.
Many contractors figure that if it has done that much work without any trouble it may be better to just replace the whole grinder - they are very low cost compared to the amazing amount of work they do.
Removing Concrete Coatings
Do you realise that thin coatings on hard concrete can be the most difficult to remove?
Did you know that most epoxies contain fine powdered sands and are not always difficult to grind?
Diamond grit size for coatings:
In general, coarse diamonds will cut through coatings better than fine diamond segments which tend to clog up with the coating material. There should be enough bite in the size of the diamond to penetrate the coating and score it so a 30/40 grit is recommended. For thicker coatings, grits of down to 10 can be used successfully. If the diamond disc is removing the coating productively then keep using it, but if it slows down you need to look at two things.
1. Perhaps the concrete is too hard and the diamonds are blunting which means you need to choose the same grit cupwheel in a softer bond. For more details see Segments - hard or soft.
2. Or maybe the coating is too thick (say over 500 microns) so you need to change to a scraper disc which will tear it off rather than grind it off. These PCD discs have small blocks of diamond.
Concrete hardness and coatings:
To grind off most coatings the cupwheel needs to grind into the concrete floor below the coating. The concrete will keep the diamonds sharp and exposed if the bond is correct for the concrete, while also removing the build up of coating that accumulates on the segment. When you have a cupwheel bond that is too hard for the concrete the diamonds will blunt and not cut into the coating properly.
At this point operators who are unaware of the problem will blame the disc for not being able to remove a coating, but it has little to do with the coating and more to do with the hardness of the concrete.
Coating friction:
Acrylics, "DIY paving paints" and some glues become sticky with the heat generated by grinding, especially with multiple coats applied over the years. These coatings soften and stick to the segments instead of breaking away cleanly. You need to try another disc when this happens as indicated below to find the best rate of removal.
Scraping instead of grinding:
Your options are to try coarser diamonds, or to try a PCD scraper disc or to take smaller bites into the coating each time. Sometimes a long handled scraper can be useful to scrape away most of the coating. PCD scraper discs will be most successful on hard concrete as will soft bond, very-coarse diamonds down to 10 grit. Coarse diamond 30/40 grit with the right bond will be better on soft to medium hardness concrete.
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