Polyurathane over epoxy

[bigjon]

Has anyone here installed polyurethane over 2 year old epoxy? I've got a section at the front of my shed 1m x 4m. Epoxy is in good shape apart from the weathering. I was going to sand (80 grit?), clean & apply the polyurethane. Any tricks or hints from any experts?
This is what I intend on using.
http://www.ppgpmc.com.au/docs/B23 7518 02-2010 SigmaDur 590 AZ.pdf
This is the epoxy I used 2 years ago.
http://www.ppgpmc.com.au/docs/B15 7466 09-2005 sigmacover 456.pdf

 

[LegacyIndustrial]

Can't speak for PPG. You will have to talk to them and request the steps involved. However, typically you will degrease, de-gloss, solvent wipe and apply your product.

One of our installers is performing this very process this weekend for a pharma. company in PA. The epoxy is approx. 2 years old. In this particular case because we don't know who made the original product we are adding a layer of our "HD" coating as a primer to avoid any potential issue, then topcoat with a high solids, pigmented, satin finish urethane.

 

[bigjon]

The PPG rep said 'sand, clean & apply', but I was wondering if anyone here had done it and could give me some tips. He didn't mention 'solvent wipe'; what solvent is that? It does seem straight forward. The epoxy is outdoors (thus the weathering) which is the reasoning behind using the polyurethane.

 

[LegacyIndustrial]

The PPG rep said 'sand, clean & apply', but I was wondering if anyone here had done it and could give me some tips. He didn't mention 'solvent wipe'; what solvent is that? It does seem straight forward. The epoxy is outdoors (thus the weathering) which is the reasoning behind using the polyurethane.

The solvent wipe will clean any potential contaminates from the sanding process and clears out any tiny particles of dust that might be hiding in the "scratches" you created in the process. Xylene, denatured alcohol, or similar will do.