We are designers and makers of sewer valves, covers and frames. We have found that most 2 part epoxy resins are cost effective for valve bodies but rely on bitumen product for the underside of covers. Ductile iron with a triple coat has had the test of time with acceptable results - however...
For clarity from the start, I am a seller as well. Sellers are very useful in these forums as they are like the specialist engineers insomuch as they have spent the time and money to develop specific solutions to specific problems as they arise. Most concerns have been an issue somewhere, some...
Pressure and odour issues are not uncommon. Purpose built covers and frames are now available with corrosion being offset with T316 parts and NBR gaskets. www.upwey.com
