Maximizing your coating productivity (and profits) starts way before you get to the job site to apply the coating. It will take good planning & estimating, the right coating & equipment and efficient execution to maximize your productivity and profits. Let’s take a closer look at these areas:
Planning & Estimating:
Always try to do a job walk
- This will let you see the project firsthand and help you determine how accessible the ductwork is which will help you determine your production rate (for cleaning and coating) and ultimately your quote/bid for the project.
- You can identify challenges and think of solutions before the crew arrives to do the work (believe me they will thank you).
- Helps you put together a good efficient work plan.
The Right Coating & Equipment
Deciding on the Coating
- If the coating is specified on the project you don’t have a choice.
- If it is not specified you can choose or recommend a coating.
- Coatings have different viscosities, dry time and odors all of which can affect your productivity. Get to understand these differences so you can choose the best coating for your project.
Deciding on application equipment
- The airless sprayer must be properly sized so it can push the coating through liquid line and hand held spray gun (normally used for spraying air handlers and large ductwork) and the liquid line and the cart or robotic system (used to spray ductwork). Using a cart or robotic system with your airless sprayer will require more hp and gpm capability that when you use just the hand held spray gun.
- Use the right spray tips for the various sizes of ductwork. 360 degree spray tips work well in ductwork under 20” high while spinning spray tips work well on ductwork from 20” to 36” high. You would generally crawl and hand spray in ductwork bigger than 36” high.
- It’s a good idea to have an extra spray tip on the job as a backup.
Make sure the surface you are coating has been cleaned first
- This may sound obvious but unfortunately some contractors cut corners and don’t clean the surface first. You can coat a dirty surface and it may hold up for a while but eventually the coated dirt will separate from the duct and that coating project will fail and need to be redone. Every coating manufacturer stresses the need for a clean surface prior to coating. Many recommend a primer in cases where the surface can’t be clean as well as it should be. The primer bonds with the imperfect surface and the coating then bonds with the primer.
- Make sure you protect desks, cabinets and other items from any overspray or drips.
Thoroughly mix and strain your coating before applying
- This step should eliminate or at least drastically reduce the chance of your spray tips getting clogged on the project. There is nothing worse than having to stop a coating project to clean out spray tips and screens. It really reduces your productivity and profits.
Coat a trial section first
- We highly recommend doing a trial section of ductwork first because it gives you a chance to:
- Determine if your airless sprayer works well with your cart spray system and coating.
- It lets you determine what retrieval/spraying rate gives you’re the level of coating you want on the project.
- It lets you and the building owner/representative agree on what is adequate coating thickness before you coat the whole project. You don’t want disagreements after you are all done coating.
Apply your coating
- You typically position your spray cart system at the far end of the duct and the spray as you pull it back toward you.
- When you get a foot or so from you access opening you stop and disconnect the cart from the liquid line and connect the hand held spray gun to the liquid line to do the fine controlled spraying around the access opening.
Inspect your work
- Inspect your work as soon as can to see if anything was accidentally missed or needs a little more coating.
- Insulated surfaces on a project may not necessarily be in the same condition throughout the HVAC system so after spraying there can be variations in coating appearance. This is a good point to mention to your customer prior to starting the project to help manage expectations.
Clean the spraying equipment
- The final step in any spraying project is cleaning the airless spray equipment and any cart/robotic spray system used. You typically run warm soapy water through all the spraying components until clean. And then you take the spray tips apart to make sure the tips and any screens are clean.
It’s the little things that you do or don’t do that will determine your success when applying coatings in HVAC systems/ductwork. Good planning, the right coating & equipment, and efficient execution will result in maximum productivity and profits. Being able to offer coating services can give you a competitive edge over your competitors who don't offer coating services or don't do it well.
If you want more information on coating HVAC systems we recommend our Introduction to Coating HVAC Systems Guide. It includes a chart on popular coatings and their characteristics along with a chart on coating and airless sprayer compatibility. quick link
Please call Peter Haugen at 855-Vac-Systems or 952-808-1619 if you have any questions about coatings, airless sprayers and cart/robotic spray systems.