Selected Answers

From Andrew Piedl of Steven Winter Associates, Inc on July 9, 2020:
I don't completely understand the question; is the ...read more I don't completely understand the question; is there a particular type of defect encountered from abrasive blasting of cast iron? Cast iron and steel are different materials with different properties. I can think of a variety of types of defects discovered in the removal of coatings from cast iron that may include cracks, corrosion, and the already mentioned 'air pockets' or pin holes that form during the casting process. Cracks can be difficult to fix (beyond my knowledge for structural capacity), but are often fixed with holes drilled and plugged at crack ends, and cracks repaired by chemical products (Belzona, JB Weld) or welding. In some instances, severely deteriorated elements may require replacement. Pin holes can be filled with chemical products.

From mauricio gomez of Jifco inc on July 6, 2020:
This is an advise about blasting cast iron instead ...read more This is an advise about blasting cast iron instead of looking for  defects found during the process of sandblasting cast iron. Working on coating and lining all kinds of pipe in my life, when blasting cast iron, I needed to select theright type of abrasive-- real light with low pressure to avoid damage on new material. If blasting old structural cast iron, you can find  air pockets caused by casting defects and corrosion issues. There is  nothing you can do about that, except if the job owners or the tolerance of the standard allows, abrasive blast to remove all corrosion issues and fill out with compatible putty and apply the new coating.

From Marco Fabio Ramenzoni of ZINGA METALL BRASIL on July 6, 2020:
This is a very interesting discussion with no answ ...read more This is a very interesting discussion with no answer to the addressed question! Come on, folks, can anyone with this kind of experience or knowledgcomment?