The Cryogenic Institute of New England, Inc.’s dry ice blast cleaning manager, Ian Scott and I headed out to Boston on September 24 to complete a dry ice blasting project involving wood joists and floorboards. The job was to be completed in a single day’s work. The room to be cleaned was situated to the side of an alley way that was located off of a one-way street. We had to position our air compressor on a curb and then run hose down the alley to the back room. Additionally, our dry ice blasting machine needed to be brought down several steep stairs, which required the use of a ramp. Setting up the job took much less time than expected considering the logistical issues associated with the dry ice blasting job.
The objective of this project was to clean wood joists and the bottom of floorboards in a soon to be renovated dining room. The wood needed to be cleaned to a bare finish that was smooth. Ideally, the end result would look like brand new fresh wood that had been installed. Before even starting our dry ice blasting process, the wood looked very old and worn. It had a feathered texture and in some sections was stained and had dirt on it. Regardless, it looked like something dry ice blast cleaning would fix without issue. It was a humid day and since we were blasting in an enclosed area between the joists, it was very hard to see the surface being blasted. The floorboards cleaned up well, but it took several sampling efforts to get the right finish.
The joists on the other hand were a completely different story. The joists seemed at first to have been stained at some point in their lifetime. But, once we started dry ice blasting the joists, a certain smell started to permeate the room, even through our respirators. The joists appeared to have been made of what would remind you of utility pole wood. After doing some further reading on the subject, I discovered that it is quite likely that the wood was finished in creosote. Creosote was created as a wood preservative dating back to 1831. The house we worked in which was over 120 years old, may have had creosote protected wood joists, which prevented us from getting the clean that both us and our customer desired. We were only able to bring a wood stain look back to the joists. Unfortunately, we were unable to bring them back to bare wood. The wood seemed to have been soaked completely through with creosote and even after dry ice blasting the texture was still not smooth. It still had that feathered look.
Regardless, we learned something from this dry ice blasting project. First, creosote coated or soaked woods will not be able to be cleaned to a bare finish that looks like brand new unfinished wood. Rather dry ice blast cleaned creosote coated wood will look like it has been freshly stained. Second, wood timbers that have a rough finish (think utility pole wood) may not clean to look like smooth sanded wood. Therefore, dry ice blast cleaning will work on creosote treated wood, but not to the extent that we have seen on other wood cleaning operations.
For more information about our Nitrofreeze® Dry Ice Blast Cleaning visit our dry ice blasting page or call us at (508) 459-7447.