Clogged GREAT STUFF PRO Gun? Here’s the Ultimate Fix!
There’s nothing more frustrating than grabbing your GREAT STUFF PRO foam gun for a project, only to find it completely clogged. That professional tool you invested in suddenly feels like a useless paperweight, bringing your work to a screeching halt.
This common problem plagues many DIY enthusiasts and professionals alike. A clean, functional foam gun delivers precise beads for sealing gaps, but a clogged one creates mess, wastes expensive foam, and costs you valuable time.
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Why Your Foam Gun Clogs and How to Prevent It
Understanding the root of the problem is the first step to a permanent solution. The culprit is simple: cured polyurethane foam. The moment the foam leaves the pressurized can and hits the air, it begins a chemical reaction to cure and harden.
When left inside the gun’s barrel or nozzle without being properly sealed, this reaction continues, creating a stubborn blockage that can seem impossible to remove. The key to a long-lasting tool is preventing this curing process from happening inside the gun in the first place.
The Golden Rule of Foam Gun Storage
The single most important maintenance tip is to always leave a can of foam attached to the gun. This keeps the internal mechanism sealed from air and moisture, preventing the foam inside from hardening. A can can remain attached for up to 30 days without issue.
When you finish a job, simply tighten the control knob on the back of the gun until the trigger won’t move. Then, store the gun upright in a cool, dry place. This simple habit is your best defense against clogs.
Step-by-Step Guide: Cleaning Uncured Foam
If you’re switching between foam types or preparing for long-term storage (more than a month), you’ll need to clean the uncured foam out of the gun. For this, you need a can of GREAT STUFF PRO™ Gun Cleaner.
This cleaner is essentially acetone in a pressurized can that screws onto the gun just like the foam canisters. It is highly effective at dissolving wet, uncured foam. Remember to wear gloves and safety glasses during this process.
The Quick Flush Method
- Extinguish Ignition Sources: The cleaner is flammable. Ensure there are no open flames or sparks nearby.
- Remove the Foam Can: In a well-ventilated area, point the gun into a trash receptacle and unscrew the used foam can. Be prepared for a small amount of foam to escape.
- Clean External Parts: Use the spray nozzle attachment that comes with the cleaner to spray and wipe away any uncured foam from the gun’s basket (the threaded area) and the tip of the barrel.
- Attach the Cleaner Can: Screw the can of GREAT STUFF PRO™ Gun Cleaner onto the gun’s basket.
- Flush the Gun: Point the gun into your waste receptacle and pull the trigger. Flush until the spray changes from foamy to a clear liquid solvent.
- Let It Soak: Release the trigger and let the gun sit for a few minutes to allow the solvent to break down any remaining foam residue inside.
- Final Flush: Pull the trigger again for a final flush to ensure the gun is completely clean. Remove the cleaner can and store the gun with the control knob closed.
This quick process ensures your gun is ready for its next use or for long-term storage. A clean tool is a reliable tool, especially when you need to perfectly fill a gap between different flooring types.
Tackling the Nightmare: How to Clean Cured Foam
What if it’s too late? What if the foam inside has already hardened into a solid plug? Standard gun cleaner will not dissolve cured foam. At this point, you have two options: attempt a manual deep clean or replace the gun.
For the determined DIYer, a deep clean is possible, but it requires patience and care. You will need to disassemble parts of the gun to mechanically remove the blockage. Be careful, as damaging internal seals or o-rings can render the gun useless.
Disassembly and Manual Cleaning
First, ensure no can is attached and all pressure is released from the gun. You’ll typically need wrenches, a small screwdriver or pick, and a cloth.
- Remove the Barrel: The long barrel of the gun usually unscrews from the main body. Once removed, you can use a long, thin rod or wire to carefully poke out cured foam.
- Clean the Nozzle Tip: The very tip of the gun can often be unscrewed. This is a common spot for clogs. Scrape it clean with a utility knife or small pick.
- Access the Check Valve: The basket where the can attaches contains a check valve, often a small ball bearing and spring. This area can get gummed up. Carefully unscrew this assembly (if your model allows) to clean out hardened foam that prevents the ball from moving freely.
This process can be complex, and reassembly is critical. If internal parts are scored or seals are damaged, the gun may leak. For many, the time and effort involved lead them to conclude that purchasing a new gun is the more efficient choice.
Foam Gun Maintenance and Troubleshooting
Proper care extends beyond just cleaning. Regular maintenance ensures your GREAT STUFF PRO gun performs reliably for every project, from small drafts to bigger jobs. Just like you’d figure out a smart way for transporting equipment without a roof rack, a little planning goes a long way.
A little preventative care saves a lot of hassle. Think of it like planning ahead for a big task, such as figuring out how to defrost a freezer without a huge mess.
| Problem | Likely Cause | Solution |
|---|---|---|
| Trigger is Stuck/Sluggish | Cured foam is impeding the trigger mechanism or internal needle. | Attempt a full flush with gun cleaner. If that fails, disassembly and manual cleaning may be required. |
| Poor Foam Flow | Partial clog in the nozzle or barrel, or the can is low on pressure. | Clean the nozzle tip. If the problem persists, flush the gun with cleaner. Try a new can of foam. |
| Foam Leaks from Basket | The seal between the can and the gun is poor, or the basket’s o-ring is damaged. | Unscrew and re-seat the can. Clean the threads on both the gun and can. Inspect the o-ring for damage. |
| Gun Sputters Foam | Air has entered the system, or the foam can was not shaken well enough. | Shake the can vigorously for 60 seconds. Purge the gun by spraying into a waste bin until the flow is consistent. |
Frequently Asked Questions
How often should I clean my Great Stuff Pro gun?
For daily use, it’s recommended to clean the gun weekly by purging it with Great Stuff™ Foam Cleaner. If you plan to store the gun for more than a month, you should clean the inside thoroughly before putting it away. It is also important to clean the gun when switching between different types of foam sealant.
What do I need to clean a Great Stuff Pro gun?
You will need a can of Great Stuff™ Foam Cleaner, which is specifically designed to dissolve uncured polyurethane foam. This cleaner can attach directly to the gun for internal flushing and also comes with a spray nozzle for cleaning the exterior. It’s also wise to have safety glasses and gloves on hand during cleaning.
How do I clean the inside of the gun?
First, unscrew the used foam can from the gun. Attach the can of Great Stuff™ Foam Cleaner, then press the trigger to flush the uncured foam out into a waste container until only the cleaner is visible. Allow the cleaner to sit for a few minutes inside the gun, and then flush it a second time to ensure it’s clean.
What about cleaning the outside of the gun?
Any uncured foam on the outside of the gun, especially on the nozzle, should be wiped away immediately using a rag with acetone or the spray nozzle on the foam cleaner can. Once the foam cures, it becomes very difficult to remove and must be scraped or cut off.
Can I clean the gun if foam has already cured inside?
Cleaning cured foam from the inside of the gun is extremely difficult as solvents like acetone and foam cleaner only work on uncured foam. Cured foam requires being mechanically scraped or chiseled out, which may not always be possible and can damage the tool. Proper maintenance involves cleaning the gun before the foam has a chance to cure.
Pro Tips for a Longer Gun Life
- Wipe After Use: After each use, give the nozzle tip a quick wipe with a rag and a small spray of cleaner to remove any residue before it cures.
- Periodic Use: If you have a can attached for storage, try to dispense a small amount of foam every couple of weeks to keep the internal parts lubricated and moving freely.
- Lubricate the Basket: Before attaching a new can, applying a very light film of petroleum jelly to the threads of the gun’s basket can help prevent foam from sticking and makes can changes cleaner.
- Never Use Sharp Objects on the Tip: Do not use a nail or screw to clean the nozzle tip. This can damage the internal needle valve, causing leaks and ruining the gun’s precision control. Gently scrape with a piece of soft wood if needed.
By following these cleaning and maintenance procedures, you can transform your GREAT STUFF PRO gun from a potential source of frustration into a reliable, long-lasting tool that’s always ready for your next project.
