Grinding Concerns

[zdumpor]

I rented a single head Husqvarna PG280 and 6 30 grit inserts. I grinded dry. I am about 1/2 way through grinding the floors once and have hit a road block.

I have two areas that I'm preparing for the High Solids DIY kit:
1. New Concrete 3 months old
2. Old Concrete 1988

The first section (180 sq ft) went about as I expected and didn't wear the inserts too bad. Maybe 1/4 down.

The second section with the old concrete was about the same square footage and wore them down completely.

I have two questions:
1. I have attached the pictures of the old concrete after grinding. The concrete looks pretty rough. Does this look right to you, or will this concrete be a bad foundation for the epoxy kit?
2. Should I expect to go through an entire set of inserts within 300 sq ft, or is that abnormal?

Before I continue with the job, I want to make sure I'm on the right track, and don't want to dump another 150 dollars on inserts and apply the epoxy if it's doomed to fail.

 

[LegacyIndustrial]

A great candidate for a full-flake kit.
Those prep scars are going to be tough to hide with anything less.

 

[Armorpoxy]

Agree, this is a very agressive grind pattern that you put on the floor. As for the tooling wearing out 300 ft seems odd to wear out a set of tooling.

The thing with grinding is that hard concrete requires 'soft bond' diamonds and soft concrete requires 'hard bond' diamonds. The only way to test the concrete for hardness is with a Moh's Hardness test kit, not something a DIY would have. Use of the wrong tooling setup will cause them to wear very fast so if you went through a set you had the wrong tooling.