Concrete Grinder

[jessehornberger]

I am Jesse Hornberger. I am interested in building this 3 axis table to hold a water fed diamond grinder used for making concrete countertops. I own a company called Imperial Concrete and fabricate concrete countertops and I also make steel sculptures. I have been using a hand held 5 inch grinder and want to get a more precise finish. I understand that I will have to adapt the plans for water use (water guards).

I want to make a machine with a 4X8 bed and be able to support about 1000lbs. this would equal a concrete slab of about 3in thick. A standard countertop is 1.5 inches thick.

I have excellent fabrication skills, and hold an associate degree in welding technology. I also have experience in CNC machining, and electrical work.

[Regnar]

Welcome aboard Jesse. I have always been interested in making a concrete counter-top. Maybe one day I will.

What does the Diamond Grinder do? I ask because the only concrete counter tops I have seen made was on a show called Rock Solid. They made a mold out of Melamine, poured the concrete and did a light sanding afterward with an orbital sander.

I always liked the look of broken glass mixed in.

[jessehornberger]

The grinding/ polishing procedure of concrete countertops is extremely important! It produces a smooth flat surface, and depending on the look the client is going for you can grind to the stone/glass aggregate inside the concrete. We grind to 200-400 grit which leaves a semi gloss finish on concrete after a finish is applied. If you would like to see some examples of my work you can visit my website at ImperialConcreteCorp.com.

[MetalHead]

Welcome !!!

I don't see why this can't be done. You would need to create a bed that would catch the slurry and not get water on the electrics. You would also need to make sure the gantry electrics are isolated from the slurry. I am sure you are wet grinding.

I can see a table with some kind of rollers (Like the ones on a boat trailer maybe) that allow you to roll the counter top on and off the table unless you already have a crane.

The next thing would be what is the down force needed for your grinder. I would not think it is a lot. Just a time thing.

I have thought about this myself because you can load the machine and just keep re running the same program over and over as you change the grit on the grinder.

How many cycles do you run for polishing your counter tops?

[jessehornberger]

So I think I killed a tree last night printing out the build plans!
As for water protection I was thinking about building a “Boot” around the actual grinding wheel. This would keep all the water localized to the cutting area and away from electronics and barring surfaces.

There does not need to be a whole lot of down pressure, when hand grinding I just use the weight of the grinder for the down pressure. The diamond pad is doing the cutting, so just feed and speed will have to be addressed to match the capability of the tooling.
As for passes, it all depends on the amount of stone aggregate you want to expose in the concrete. If no aggregate is to be exposed it is about 2 passes. One with a 100 grit pad, and the second with 200 grit.

If stone is to be exposed we start at 30 grit, then 50, 100, and finish with 200.

What is the average build cost for a project like this?

[hennie]

Jesse I like those tops, I like the way the under mounted sink sits with the drip tray.
Nicely done.Do you reinforce the tops with some wire mesh to make it more ridgid?If you have a joint how do you join it?

[jessehornberger]

We use a 3/16 reinforcing wire with 125,000lbs tensile strength. We have an engineered calculation for how many strands are necessary in a particular sized piece. When placed in areas of tension it produces a very strong “beam” structure. A 36 inch cantilever is able to support upwards of 800lbs!

Joints are filled with a kitchen and bath silicone caulk that is color matched using the same pigment that is in the concrete.

[Regnar]

Jesse, Great site.

The cost will be totally up to you, what you can salvage and make yourself. I haven't finished mine yet but I am looking at just under 5,000 for a 4ft x 8ft table with belt drives. The largest chunk of the change going towards control box.

The best way to save money is to read this forum. A lot these guys have done some great leg work and found some great sources. Its just a matter of finding them in the forum now. Another way is have a plan and try not to buy things twice if you can avoid it.

[MetalHead]

Jesse I sent you a PM on the Laser Cut and other Parts you will need for youe build.

[jessehornberger]

I am going to spend some time looking over the plans and materials. I’ll let you know when I start the build, and of course ask any questions if I have any!

[lunaj76]

Jesse,

Why don't you just make a mechmate with mods to do your grinding and a router to build your forms? Just a thought. I am speculating you use melamine forms. Welcome to the forum!

[Johannescnc]

Hey Jesse, very cool. It looks like terrazzo.