New Epoxy coat

[Theruse]

I have a 20 year old Griot's epoxy coating that needs to be repainted before I put in my new lift. I am thinking of renting a floor sander to get back to the bare concrete so I can get a good bond. Any suggestions on paper grade and do I need to use TSP to etch the floor again or am I OK with just sanding.

 

[benwah]

Is the epoxy bonded securely to the floor? Is it chipping or failing in any areas?

100 mesh sanding screen works great for something like this if the old coating is sticking well.

Sand > solvent wipe > re-coat

 

[Theruse]

The old coating is holding well. Just worn through to the concrete in a few areas after 20 years. Also a few chips in concrete where my jack fell and chipped the concrete

 

[benwah]

I suggest feathering edges of chipped concrete and old epoxy by hand and attempt to make a smooth transition. If you can do this mechanically, great.

Use a 100% solids epoxy filler/surfacer to fill all chipped and worn down areas, let cure and sand even with floor before re-coating