How do you spray foam packaging?

Spray foam packaging is a method of creating protective packaging for fragile items using polyurethane foam. The foam is sprayed directly into a cardboard box or other container, surrounding the item with soft yet rigid cushioning. Spray foam packaging has become popular in recent years as it is lightweight, customizable, and provides excellent protection against impacts or drops. Here is an overview of how to properly spray foam package an item.

Choosing the Right Foam

The first step in spray foam packaging is selecting the right type of polyurethane foam. Two main types are used:

Open-cell foam – Soft and flexible, with small air bubbles throughout. Best for delicate items.

Closed-cell foam – More rigid and dense. Best for heavy items requiring firm support.

Closed-cell foam is available in different densities, rated as “pcf” (pounds per cubic foot). Higher densities around 4-8 pcf are best for shipping sturdy items while lower densities around 1-3 pcf are good for fragile objects.

The foam should also have a high R-value, indicating good insulative properties. R-values of around 6.0+ per inch of thickness are recommended for foam packaging solutions. This helps maintain temperature control in shipping.

Choosing a Spray Foam System

Applying spray foam requires a spray gun connected to a pressurized system containing two liquid chemical components: polyol resin and isocyanate. When these components mix in the spray gun, an exothermic chemical reaction occurs that causes the liquid to expand into rigid foam. Professional spray foam insulation kits are available with everything needed to get started.

There are two main types of spray foam application systems:

Portable systems – Best for small businesses or occasional use. These feature refillable tanks fed into a lightweight spray gun. Tank sizes range from 10 to 60 gallons. Portable systems are lower output but easier to maneuver and store.

Dedicated rigs – Ideal for shipping facilities doing high volume spray foam packaging production. Dedicated rigs feature large chemical drums feeding into an industrial spray gun via heated hoses. Output is very high but requires significant storage space.

When selecting a spray foam system, consider your production needs, available space, and budget. Portable systems provide the most flexibility for small operations.

Preparing the Workspace

Once you have your spray foam equipment, you need to set up an appropriate workspace. Here are some tips for preparing your spray foam packaging area:

Work in a well-ventilated area – vapors from foam chemicals can accumulate quickly in enclosed spaces.
Cover surfaces with plastic sheeting – spray foam adheres to most surfaces and is difficult to remove once cured.
Have the item pre-boxed before spraying – trying to box an uncured foamed item will deform the foam.

Wear PPE – use a respirator, gloves, and protective suit to minimize exposure.
Stage foam chemicals nearby – have spare tanks ready to avoid running out mid-application.
Ensure adequate electrical supply – heating hoses and pumps requires significant power.

A dedicated spray area with vinyl floors and plastic-covered walls is ideal. Make sure to position adequate ventilation to carry away fumes. The space should also be temperature controlled between 60-80°F to facilitate proper curing.

Filling the Spray Gun System

Before foam application can begin, the spray foam chemicals need to be loaded into the system tanks/drums and connected to the spray gun hoses. Follow all manufacturer safety instructions during this process. Key steps include:

Make sure all containers and hoses are empty before refilling.

Wear chemically resistant gloves, goggles, and coveralls.
Carefully fill tanks with polyol resin and isocyanate using proper transfer pumps.
Securely fasten all hoses, valves, and connections.

Turn on heating system to bring chemicals up to the desired temp (often 120-140°F).
Allow chemicals time to heat up before spray application.

Properly filling and preparing the foam system helps ensure consistent foam quality and makes the application process easier and safer.

Applying the Foam

Once your foam packaging system is prepped, you’re ready to start applying foam directly into boxes. Here is the basic spraying process:

Don protective gear – respirator, gloves, full coveralls.
Position the box in the center of the workspace, away from any walls or obstructions.

Hold the spray gun 18-24 inches from the bottom of the box to begin foaming.
Trigger the spray gun in smooth back-and-forth sweeping motions to build up even foam layers.
Work progressively up the sides until the box is about 2/3 filled with foam.

Fully encase item in the center of the box, then finish foaming the top.
Allow foam to cure for at least 24 hours before handling.

Maintaining consistent sweeping arm motions results in uniform foam with the best protective properties. Leaving a small gap at the top allows trapped gases and heat to escape during expansion and curing.

Spray in layers approximately 2 inches thick, allowing 10-15 minutes between each layer for cooling. Thicker layers risk excess heat buildup which can deform the foam. Most items require at least 3 layers for sufficient cushioning effect.

Foam Curing and Box Handling

Once the spray foam application is complete, the box must be allowed time to fully cure before being shipped or handled:

Let foam cure 24 hours before moving the box.

Optimal full cure takes 5-7 days, do not ship before then if possible.
Keep boxes at room temperature 60-80°F during curing.
Higher heat and humidity will accelerate curing.

Do not stack boxes or place other objects on uncured foam.

During the curing process, the foam will firm up and form a durable cushion around the contained item. The foam may shrink slightly but will maintain excellent shock absorption properties.

Fully cured boxes may be stacked or moved safely. If kept protected indoors, spray foam packaging can last for many years.

Cleanup and Maintenance

With proper care, a spray foam packaging system can provide years of reliable service:

Flush hoses – Run hose cleaning solvent through after each use to prevent buildup.
Cap containers – Seal all chemical drums and tanks to maximize shelf life.

Clean spray gun – Follow manufacturer instructions to prevent clogging.
Inspect equipment – Check hoses, connections, seals, and tanks periodically for any wear or leaks.
Change filters – Replace gun filters and inline strainers per maintenance schedule.

Keep the area clear of any residual foam and clean spills right away with polyurethane foam cleaner. Proper cleanup habits will help prevent potential foam quality issues down the road.

Safety and PPE

While extremely useful, spray polyurethane foams involve some safety considerations:

Wear full protective equipment when spraying – respirator, gloves, coveralls.

Use spray foam only in well-ventilated areas.
Avoid exposure to uncured foam fumes which can be hazardous.
Monitor skin for any reaction to foam chemicals which can cause irritation.

Store foam chemicals securely away from heat sources or open flames.
Dispose of waste properly. Foam cannot be recycled.

Always read and follow all safety instructions provided by the foam manufacturer. With proper precautions, spray foam can be used safely by trained operators.

Advantages of Spray Foam Packaging

Here are some of the main benefits of using spray foam packaging:

Lightweight – Foam is up to 90% air, reducing shipping costs.
Custom Fit – Foam molds perfectly to complex and irregular shapes.

Excellent Cushioning – Soft yet rigid foam absorbs impacts very effectively.
Temperature Insulation – Foam provides insulation against heat and cold.
Minimal Vibration – Foam dampens vibration during transport.

Water Resistant – Closed-cell foam resists moisture absorption.
Reusable – Boxes can be reused multiple times in some cases.

The cushioning performance and reliability of spray foam makes it ideal for protecting fragile, sensitive, or valuable items during shipping and storage.

Potential Drawbacks

While having many benefits, there are some potential downsides to keep in mind with spray foam packaging:

Higher upfront costs for equipment purchase and installation.
Recurring chemical costs which may be pricier than loose fill options.

Space required for equipment and chemical storage.
Specialized operator training required for safe use.
Regular cleaning and maintenance needed to avoid issues.

Some chemical sensitivity concerns among consumers.
Not reusable or recyclable, disposal can be challenging.

The convenience and performance of spray foam has to be weighed against the larger investment and operating costs compared to alternatives like loose fill peanuts.

Cost Analysis

Here is a comparison of approximate costs between spray foam packaging and traditional loose fill methods:

Method	Equipment Cost	Consumable Cost
Spray Foam	$3,000 – $8,000	$0.25 – $0.40 per ft3
Loose Fill Peanuts	$500 – $1,500	$0.10 – $0.15 per ft3

While spray foam requires a larger up front investment, it can pay for itself in some high volume shipping operations where foam’s performance justifies the higher costs. Lower volume applications may do better with loose fill financially.

Best Practices

Follow these tips and best practices when using spray foam packaging for optimal results:

Use the right foam density for the item’s weight and fragility.
Maintain steady back-and-forth sweeping arm motions when spraying.
Apply foam in layers, allowing proper cooling between each.

Fully encase item in the center with at least 3 inches of foam minimum.
Let foam fully cure for 5-7 days before handling boxes.
Keep spray work area ventilated and free of obstructions.

Wear full chemically resistant protective gear when spraying.
Follow all equipment and chemical manufacturer safety instructions.
Inspect and maintain equipment regularly to prevent issues.

Alternatives to Consider

While spray foam is advantageous for many applications, here are a few other packaging options that may suit some situations better:

Molded Pulp – For lightweight fragile items. Made from recycled materials.
Loose Fill Peanuts – Traditional method, very low cost.

Inflatable Air Bags – Adjustable void fill, but can be punctured.
Formed Foam – Prefabricated foam shapes. Less messy than sprayed.

Looser fill methods allow items to settle during shipping which may be unsuitable for some cargo. But they provide a cheaper alternative to spray foam’s more involved process.

Frequently Asked Questions

Is spray foam packaging reusable?

In some cases spray foam packaging can be reused a few times if the foam remains intact. However it will gradually break down over multiple uses. Single use is recommended for most applications where high performance cushioning is needed.

Can you overfill a box with spray foam?

It’s possible to overfill a box which can create backpressure as the foam expands and result in damaged foam structure. Leaving 2-3 inches of space at the top is recommended for proper rising and curing.

Does spray foam stick to items?

Uncured spray foam is sticky and will adhere firmly to surfaces. Greasing items first or encasing them in plastic bags prevents sticking. Cured foam will not stick.

Can spray foam get wet?

Closed cell spray foams resistant moisture fairly well but excess water absorption can still damage the foam structure. Electronics and other water-sensitive items should still be sealed in plastic before foaming.

What’s the shelf life of spray foam chemicals?

Properly stored in sealed containers between 60-80°F, the two main spray foam components typically last approximately 6 months from manufacturing date before quality degradation occurs.

Conclusion

While requiring some investment upfront, spray polyurethane foam can be an extremely effective protective packaging method when done properly. Following safe handling procedures and allowing for full curing produces rigid, lightweight foam with unbeatable cushioning performance. Spray foam packaging excels at shielding fragile and sensitive contents from the rigors of transportation and storage.