Commercial spray foam insulation equipment typically requires flushing when you switch from closed- to open-cell foam and vice versa. Why is this action necessary? There are numerous differences in the formulations of open- and closed-cell spray foam and mixing the two formulas can result in a reaction that could potentially cause issues.
We recommend to our contractor customers that they utilize a dedicated SPF proportioner for open- and closed-cell foam if they regularly use both materials.
Also, if you tend to switch between brands of the same kind of spray foam, there may or may not be a reaction should the two liquids mix. So, it can be difficult to respond with a straightforward ‘yes’ or ‘no.’
One easy way to figure this out is to use a small amount of the liquid material of each and combine them in a clean, dry container. If there is no reaction, then your equipment should not require flushing before you put any new foam into the machine. However, if you notice particles, coagulated liquid, or increased stickiness, then you should flush the machine.
One point to keep in mind is that there is more likely to be a reaction when switching between open- and closed-cell foam than switching brands of closed-cell foam. Even if there is no reaction, you should be extremely careful not to spray a mixture of different spray foam insulation kits when following with one type of another material. The resulting foam can end up as a hybrid that does not have the proper physical properties of either type of material.
We suggest SPF contractors take the following steps to reduce the chance of spraying mixed-element foam:
- Before you insert a transfer pump into the new drum, clean it and remove all traces of old material.
- Always pump out the old liquid into a clean bucket until your new material is fully in the hoses. You can use most of the material again and dump it back into the original foam drum. Keep in mind, there will be about a half a gallon of material that is a mixture of the old liquid and the new. You should never reuse this material. Be sure to mix the B-side with the A-side to create foam and check with your local, state, or federal regulations regarding proper disposal.
- Before your next application, spray a small sample of the new foam onto a clean, dry surface to confirm that it has the correct physical properties.
A Few More Resources
Here are a few of the highlights:
- Much of your SPF equipment requires electricity and compressed air. Check that your air and power supply can generate enough pressure to drive your equipment. Make sure the air is clean and dry.
- To avoid issues resulting from inconsistent power, check your power supply going to your proportioner with an amp clamp meter on a regular basis.
- If you are using a generator, always confirm that it has plenty of fuel. Most manufacturers include lights on their generators to alert you when power is correct.
- When unusually large particles find their way into your proportioning pump, it can lead to issues. To avoid this scenario, check the machine’s Y-strainers before using any new material.
Spray Gun and Heated Hoses
- Inspect and clean the filter screens in your spray gun daily, or when material pressures seem off-balance.
- Before each application, remove the entire hose from its hanging rack before you crank up the heat. Otherwise, you risk putting undue stress on the hose length on the frame that supports the weight of the bundle, which can cause damage.
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