How to Properly Use a Foam Spray Gun

Time Of Info By TOI Staff   November 1, 2023   Update on : November 1, 2023

Foam Spray Gun

Conditions must be ideal in order to effectively spray foam, so make sure all preheaters and line heaters are running as well as that the substrate has been sufficiently warmed up before spraying begins. Additionally, it is important to clean the foam spray gun thoroughly after each use to prevent clogs and ensure optimal performance. 
Here are a few tips to make the process more manageable.

1. Use a Two-Finger Trigger

Foam guns are handy tools that attach to the end of your garden hose and use spray foam on surfaces to meet your desired objectives. Proper usage requires steady hands; initially it may prove challenging; taking the time to learn this tool’s use will ensure optimal results for your car wash, saving both money and effort in the process.

Make sure your foam gun has the appropriate metering tip for the material you are applying, and that its settings are optimal. A standard foam gun usually comes equipped with blue for low water pressure, green for medium pressure and yellow for high. Ensure the nozzle points directly toward the surface or gap you are filling before lightly pulling its trigger to start the foam flow – then fill as it expands!

For the best results, purchase your foam gun and expanding foam from a reputable dealer such as They offer a wide variety of foam guns and expanding foams to suit your needs, and their knowledgeable staff can help you choose the right products for the job.

Be careful when filling gaps or holes with foam as this could force the seal back into its original location on the door or window jamb. To prevent this, use minimal expanding foam specifically designed to do this and apply multiple layers, allowing each one to expand fully before adding another one.

2. Don’t Drag the Tip

Spray foam guns are designed to work with standard garden hose pressure, so no special high-pressure washer is required to use one. However, it is essential that only fill your gun according to what’s recommended on its label; otherwise, using too much soap could result in too thick a mixture or insufficient suds production.

Foam can be applied using an adjustable foam gun to a variety of surfaces – windows, doors and walls to air seal homes – using two styles of adjustable guns: classic Gilmour designs or the more recent version that can attach directly to garden-variety water hoses.

Ensure the gun remains 18 inches from the substrate when spraying foam to avoid squashing its expansion and forceful contraction.

Don’t drag the tip across rough surfaces such as concrete or steel as this may damage its valve at the end and lead to leakage.

Periodically, you should clear out your gun barrel to prevent buildup of foam that could clog its nozzle and stop its flow of foam. To do this, unscrew your gun, take some gun cleaner, spray some onto a cloth rag, then wipe your tip clean.

3. Make It a Habit

Foam guns can make car washing easier. By producing thicker foam that adheres more securely and pulls more dirt with it, these spray foam guns provide superior cleaning power. However, using one requires special attention: you must ensure it remains clean between uses, use appropriate supplies and adhere to manufacturer recommendations regarding soap formula.

Pour your car wash foam soap into a gun according to its recommended levels and mix it with water. Be sure that your mixture is slightly warmer than room temperature as this helps the foam expand and set faster.

It is crucial that the foam be mixed at an optimal temperature in order to achieve maximum results from its spray application. Too hot can cause it to expand beyond control and fail to adhere to its substrate; too cold will remain as an unbonded mass on top of your substrate with crackly texture similar to pork rinds.

Flushing your lines is a straightforward and quick solution to these issues, taking only about 10 minutes and being very straightforward. First, separate your spray gun from its hose, disconnect barrel pumps, then open only A-side valve in your fluid block to connect end of hose to gun; barrel pump will recognize pressure difference and flush entire A-side line from can to hose and spray gun tip.

4. Clean It Up

Spray foam guns require regular maintenance to stay working at their best. Luckily, it’s simple to keep both your gun and hose lines clean with the appropriate solvents; keeping these handy will help avoid potential cross-overs, poor foam coverage and other potential issues that come from having dirty guns on hand.

Dyn solve can quickly remove cured polyurethane foam deposits from your gun and hose, as well as loosen and remove polyurethane reactive hot melt (PUHRM) adhesives from roll coating or dispensing equipment.

Cleaning your gun and hoses regularly will save you time, money, and energy in the long run. One effective strategy to ensure that your nozzle operates optimally is flushing it daily before spraying – an easy 10-minute task which only takes place daily! To flush, separate your gun from its hose, open only A-side barrel then push end of spray hose over it several times until A-side line opens and closes, stopping crystallized iso from building up in barrel and gumming up gun. Take this time to stir B-side line before beginning open cell spraying so they warm up fully before beginning spraying and to turn on all preheaters/hose/heating units that need warming up fully as part of this daily ritual!

Read more: How to Properly Use a Foam Spray Gun


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