Selected Answers

From Lydia Frenzel of Advisory Council on October 31, 2016:
Being the "Water Witch of the West," I agree with ...read more Being the "Water Witch of the West," I agree with Warren Brand that you should look into high- to ultra-high pressure waterjetting. Older coal tar coatings tend to soften with abrasive cleaning. It is relatively straightforward to sump up the coating/water, filter out the larger solids, check the water quality, and recycle the water if necessary after finer filtering, and resin exchange (if needed to reduce conductivity). You can always allow the effluent water to evaporate if you want to reduce waste to a minimum. I am assuming that you are planning to recoat the surface. You will need to check the profile under the coating.

From K Sanchez of CSP on October 3, 2016:
Because some of the other abrasives mentioned are ...read more Because some of the other abrasives mentioned are one-use abrasives, they would not be appropriate under the Resource Conservation and Recovery Act (RCRA). RCRAis a regulation requiring users to reduce the amount of waste generated, through source reduction and recycling. Steel grit, which can be reused and recycled, allows users to be compliant and much more efficient in their blast. Steel grit removes both crusty and soft coal tar.

From Warren Brand of Chicago Corrosion Group on September 29, 2016:
It depends. If it's hard and brittle, coal slag, ...read more It depends. If it's hard and brittle, coal slag, crushed glass, etc., would be fine. However, some old materials will be hard and crusty on top, and softer and gooey (pardon the technical jargon) underneath. If that's the case, I'd look to high- or ultra-high-pressure water jetting.

From Shane Tierney of Hertel Ireland Ltd on September 26, 2016:
The best media for removing epoxy coal tar is copp ...read more The best media for removing epoxy coal tar is copper slag.  A medium or coarse grade will do the job.