Exhaust Paint Stack Cleaning – Dry Ice to the Rescue

Here at Indigo we’ve become adept at cleaning paint exhaust stacks.  This experience has come over years of learning about the various types and styles of stacks, there are a nearly unlimited combination of stacks out on the market, from top draw fan units, to mid-stack and booth top fans, 48” wide stacks to 20” stacks and all the permutations in between.

Paint exhaust stacks are an ideal candidate for being cleaned on a regular basis using dry ice blasting.  Dry ice blasting generates no dust from the dry ice blast pellets which convert back to a gas on contact, it does not generate any moisture to cause headaches with clumping old paint, and it is fast in the vast majority of applications.  An added benefit is dry ice blasting can also clean the exhaust fans without any worries of damage to the motor or electrical disconnection requirements.

Here’s the basic process.  We contain the debris field by tarping or other tenting, then start at the top and clean down to the booth.  Often we also clean the plenum, the area around and behind the filters.

We typically route the cleaning equipment up through one of the stacks, so just the operator(s) and the business end of the blast nozzles are on the roof.  We then begin cleaning any cowling or “hat” on the stack, or the fan if it happens to be a top mount fan, then start blasting downward with dry ice blasting and usually some hand scraping

to clean the surface.  Many times we use custom tools and nozzles we have created for just this purpose, to reach into angled stacks or long runs.  We continue down until we reach a fan if it’s mounted internally, then we move down to the booth and clean the underside of the fan and on down to the booth.  As mentioned above, we clean the next stack and so on until all are cleaned. 

Once all stacks are cleaned we clean off our equipment and sweep up all the dust that landed on the booth floor and dispose of it on site in dumpsters or trash receptacles.

Some tips that lower costs and improve efficacy.

1. Cleaned exhaust stacks and fans greatly increases the efficiency of the exhaust system, which contributes to better quality by preventing coating fallout from landing on parts in your process. 
2. Cleaning the stacks regularly pays dividends in the increased efficiency, and by happy coincidence also lowers the cost of routine cleaning since a stack that is regularly cleaned goes much quicker than one that has a year or 20 of buildup.
3. Frequency of cleanup depends on how often your booths are used.  If you are spraying three shifts a day, every day, you probably should clean them at least once or twice a year.  The quality of the fan, the filters in the booth and the skill of the applicator also affect this timetable, so there are a variety of factors at work.
4. If you only use your booth periodically, and have a good filter system, you might not need to clean it more than once every two or three years.
5. If you ask me, you should clean your paint stacks many times a year, and you should let Indigo do the work!  But a good contractor will give you good advice about how many cleanings you should do, we find that we generate trust and goodwill by not trying to push more cleanings than are necessary for optimal results.
6. Not every painting or coating product reacts the same to both booth buildup and cleaning speed.  High temp paint and epoxies are difficult, some solvent based paints dry so quick that it’s more a dusting process than a blasting process,
7. Bolts and protrusions into your booth stack attract the biggest paint buildup, so good stacks have the bare minimum of obstructions.  Avoid have a bolt nut inside the booth, try and keep the bolt head inside the booth, and make it a carriage bolt type that’s low profile and rounded.  Same goes for assembly of stack sections, make sure they are smoothly connected.
 

As mentioned, every system is unique, so yours may have twists or tricks that need to be learned to clean them efficiently.  Often, we can create a tentative plan from photos or short videos, so don’t hesitate to reach out for a no obligation consultation.

Fan before and after dry ice blasting