Selected Answers

From Jim Gooden of Blastmaster on August 21, 2019:
This is a really good question and one that we are ...read more This is a really good question and one that we are often asked. Thick coatings are often difficult to remove as the thicker the coating, the slower it is to blast, using conventional blasting systems. We have found that using 2 or more technologies can provide improved productivity and reduced cost. The conventional thinking has been to use a coarse abrasive, and depending on the thickness of the coating to be removed, this approach can still be effective. There are many technologies available, but I will mention 4 we have seen used successfully. 1) The addition of a technology like induction coating removal to remove the coating can significantly increase the removal rates, so long as there is no problem in heating the top 1/32" of the steel to almost red hot. This releases the coating and it can be scraped off. 2) Another technology that we have seen used very successfully is UHP Waterjetting. Vacuum attachments can be used. The ability of a 40,000 psi waterjet to cut through and remove coating is often several times faster than abrasive blasting on coatings over 1/4" thick. UHP water cleaning speeds do not vary much as the coating is thicker, where abrasive blasting will rapidly decrease in production for thicker coatings. 3) Using a scraper to remove some coatings will also achieve good results. In areas where a coating is partially delaminating, this can be very fast. Ride-on scrapers that are commonly used to remove floor tiles and linoleum can be fitted with a narrow blade and extra weights to help cut through the coating and remove it. Residual coating can then be cleaned up with another method.4) There are some abrasives now available with blended grading specifically engineered for thicker coating removal. They have a coarse paticle range to cut through the coating and a finer particle range to clean the surface quickly. These have made abrasive blasting more effective than has been possible in the past. I'll include a 5th technique we have seen employed very effectively. Elastomeric coatings when blasted will often heat up and become 'gummy' with the abrasive impact. By working a larger area with the blast nozzle and coming back 3 to 4 times so that the coating stays cool and harder, we have found improvement in blasting productivity by 80-100%, instead of blasting the coating off all in one pass. On both ship decks and tank floors we have seen that once the coating is removed, shotblast machines or abrasive blasting can then be used to quickly create a surface that is clean with a consistent profile that can be coated.

From Jon Cavallo of Jon R. Cavallo PE LLC on August 19, 2019:
Many contractors have had good results by removing ...read more Many contractors have had good results by removing thick film elastomeric coatings using encapsulated blast media (SSPC-AB 4).

From Zenith Czora of Durotech Industries, Inc. on August 19, 2019:
Depending on the degree of the adhesion of the ela ...read more Depending on the degree of the adhesion of the elastomers to the substrates, environment-friendly chemical stripping might be needed, or using a heat gun to soften the elastomers and scraping off the softened coating and water-jetting the remnants of the elastomers.

From Lydia Frenzel of Advisory Council on August 15, 2019:
Use Ultra-High Pressure waterjetting, preferably w ...read more Use Ultra-High Pressure waterjetting, preferably with vacuum attachment.