This post is coming out a little later than I wanted it to, but we have had a very busy few weeks here in the lab. We had some outdoor projects to finish before the weather turned cold. Some of our activities in the last few weeks have included assembling and installing a new anode rig in the tank holding the pieces we used to test the dry ice blasting, winterizing the tank farm and having adventures in the skeg tank. The skeg tank adventures will get their own post after Thanksgiving, today I want to tell you about dry ice blasting.
We were fortunate enough to have the opportunity to try out a SDI Select 60 dry ice blaster from Cold Jet. The set up for this machine is not overly complicated. You hook it up to an air compressor; load the hopper with either dry ice pellets or blocks, in our case we found that pellets worked better, the block or pellets are pressed into an auger that shaves them and then the shaved pieces are fired down a hose and out a nozzle held by an operator. The system set up is not so different from other abrasive cleaning methods, but the unique thing about dry ice blasting is that there is no aggregate left at the end to clean up. If you are doing abrasive cleaning using glass beads, sand, ground walnut shell or any other medium you will have to clean bits of that medium off of your object when you’re done. You get to skip this step with dry ice blasting since your medium just sublimates away.
We will need to do more testing and Will has some samples to analyze, but after cleaning some lower hull plates I am willing to say that the results look pretty positive. The comment was made more than once that dirt and corrosion product flew off the surface of the objects. Hopefully this is a cleaning technique we will be able to use again in the future.
Check back soon for lab activity updates and Happy Thanksgiving from everyone here in the Monitor Lab.
Will adding dry ice pellets to the hopper.
Dave blasting away. Everyone got a turn. It was very fun.
Dave blasting and Will keeping an eye on the machine.