Spray foam can be hard to get used to, especially on the first try or on a new piece of equipment. Depending on the material mixture, you could end up with awkward foam lumping or a string pattern that doesn't quite match up with what you wanted. To understand a few common misfiring, material mix, or other problems that happen with spray foam systems, here's a few troubleshooting concepts to be ready for most problems.
Bad Spray Patterns
When spraying foam, an even distribution needs to hit your desired surface with a decent amount of accuracy. It doesn't need to be a perfect application to the very millimeter, but there shouldn't be any streaks or giant clumps that happen on a regular basis.
Every foam gun or spray nozzle is designed differently. In general, they're supposed to be some sort of fan or cone shape to either spray general circles of foam or a line of foam across a broad area. If you're getting a solid stream, jagged lines, or sputtering, there a few things to check.
First, make sure you're using the right kind of nozzle. If the spray pattern is a consistent line, you might be using a straight nozzle designed to simply fill spaces instead of being in a wide pattern.
Next, check the nozzle itself for any solidified material or other blockage. The manufacturer will have warnings and suggestions about what to use, but if you're in a pinch, a thin and clean piece of wood or a very careful use of a screwdriver will be fine.
Finally, check the connections between the nozzle, spray gun, hose, and mixing chambers. Every connection area that changes the path or flow of the foam can lead to consistency changes if loosened or blocked.
Weak Response Or No Foam Delivery
Clogging is only one part of the weak or no foam problem. You should check the foam sprayer system for clogs and make sure that any nozzles or locks are turned to the on or open position, but there are a few causes that are harder to see.
First, what kind of sprayer power do you have? Are you using a pump sprayer or something with a powered pump or feeder? For hand pump sprayers, make sure that air pressure is being built up by checking the pressure gauge. If there is no gauge, the pump should become progressively harder to push as pressure builds up. If the handle is still moving too easily, the container or pump may not be closed or may need to be serviced by a professional.
If you're using a powered pump, the same opening problem exists. Close/tighten any container lids, connectors or valves--including the spray nozzle if applicable--to make sure that pressure is still building up. Open the nozzle again and attempt to spray.
Contact a spray foam equipment professional, like Spray Equipment and Coatings Inc, to discuss other troubleshooting steps, or to get equipment that works better for your situation.