What dissolves cured great stuff?

Great Stuff expanding foam is a polyurethane foam sealant used to fill gaps and cracks in building structures. It comes in an aerosol can and expands after being sprayed in place. Once cured, Great Stuff is rigid and water resistant. While useful for insulation and sealing, removing cured Great Stuff can be tricky if it has been applied incorrectly or needs to be removed for other reasons.

Can acetone dissolve cured great stuff?

Acetone is a commonly used solvent, but it is not very effective at dissolving cured polyurethane foam. Some foams may swell slightly when exposed to acetone, but acetone does not fully dissolve or break down the foam. This is because the chemical structure of cured polyurethane foam is different from the uncured components. Once the foam expands and hardens, the polymer chains cross-link and form a rigid plastic that is unaffected by acetone. So unfortunately, acetone does not work well to remove cured great stuff foam.

Does alcohol dissolve great stuff foam?

Like acetone, alcohol does not dissolve cured polyurethane foam very well. Isopropyl alcohol may cause slight swelling, but it does not breakdown the foam’s polymeric structure. The cross-linked rigid foam is impervious to dissolution by alcohols. Using alcohol to try to dissolve great stuff foam after it has cured will not be very effective.

Can WD-40 dissolve cured expanding foam?

WD-40 is another common solvent, but it also does not dissolve cured polyurethane foam. WD-40 may be able to penetrate the outer skin of the foam and cause some swelling, but it does not degrade the foam’s internal structure. Like other solvents, WD-40 just cannot break down the tough cross-linked bonds in hardened foam. So WD-40 does not truly dissolve great stuff foam once it is fully cured.

Will paint thinner dissolve expanding foam?

Paint thinners and mineral spirits also do not break down cured polyurethane foams. The active ingredient in many paint thinners is a hydrocarbon solvent like naphtha or white spirit. While effective with some adhesives and paints, paint thinner simply cannot dissolve the rigid plastic matrix that makes up cured foam. Paint thinner may be able to soften the outer skin slightly, but does not provide an effective way to remove hardened expanding foam.

Can you use gasoline to dissolve great stuff foam?

Gasoline is another common solvent, but it still does not dissolve cured polyurethane foam sealant. Like acetone and other solvents, gasoline just cannot break down the tough cross-linked structure of hardened expanding foam. Gasoline also poses much higher risks due to its flammability and environmental toxicity. For safety reasons, gasoline should never be used to try to dissolve great stuff or any other hardened foam.

Does bleach dissolve polyurethane foam?

Bleach and other chlorine-based cleaners also provide no benefits when trying to dissolve cured polyurethane foam. Bleach can react with uncured foam components, but once the great stuff foam has fully expanded and hardened, bleach is no longer reactive with the plastic polymer matrix. Bleach has no effect on the rigid structure of cured foam. Do not try to use bleach as a way to dissolve great stuff foam once it has already hardened.

Can you use brake cleaner to dissolve expanding foam?

Some brake cleaners are formulated with aggressive solvents in order to remove oil, grease, and brake fluid from brakes and automotive parts. However, even these heavy duty solvents do not dissolve cured polyurethane foam. The cross-linked rigid structure of the hardened foam cannot be broken down with the solvents in brake cleaner. So this is not an effective method for removing cured expanding foam sealant.

Will turpentine work to dissolve hardened expanding foam?

Turpentine is derived from pine resin and is sometimes used as a heavy duty degreasing agent. However, turpentine is unable to dissolve rigid polyurethane foam once it has fully cured. The complex polymeric matrix that makes up the hardened foam is unaffected by turpentine. So this traditional solvent unfortunately does not provide an easy option for removing cured expanding foam from surfaces.

Can MEK (methyl ethyl ketone) dissolve cured foam?

MEK, also called butanone, is an aggressive solvent used in many industrial applications. It is stronger than acetone and many other common solvents. However, MEK still cannot break down the cross-linked structure of cured polyurethane foam. MEK may be able to soften a thin outer layer of fresh foam before it fully cures, but it does not work to dissolve foam once it has hardened completely. So MEK does not provide an easy way to remove cured expanding foam.

Will xylene dissolve hardened expanding foam?

Xylene is an aromatic hydrocarbon solvent commonly found in some paint thinners and automotive products. However, even this strong solvent cannot dissolve the rigid plastic polymer that makes up cured polyurethane foam. Xylene and other aromatics like toluene have no effect on the cross-linked foam matrix once it is fully hardened. So xylene and similar solvents do not offer a solution for removing cured expanding foam.

Can you use oven cleaner to dissolve expanding foam?

Oven cleaners use extremely alkaline solutions, like sodium hydroxide or potassium hydroxide, to break down baked-on grease and food residue. However, these caustic chemicals do not dissolve cured polyurethane foam. The heat from an oven also provides no benefit, as cured foam remains stable up to temperatures over 200°C. So standard oven cleaners have no effect on rigid expanding foam once it is fully hardened.

Will Goo Gone work on cured expanding foam?

Goo Gone is an adhesive remover gel marketed for eliminating sticker residue, gum, and other sticky messes. It uses citrus oil extracts as a natural solvent. However, Goo Gone and similar citrus-based adhesive removers have no effect on fully cured polyurethane foam. The citrus oils cannot penetrate or break down the rigid cross-linked structure of hardened expanding foam sealant. So Goo Gone does not provide an easy option for dissolving great stuff foam once cured.

Can you use aircraft paint remover to dissolve foam?

Chemical paint strippers used for removing aircraft paint are extremely harsh caustic solutions. Products like methylene chloride work by attacking the polymer structure of paint. However, these same products have no ability to dissolve rigid cured polyurethane foam. The cross-linked foam structure is unaffected by even these highly aggressive paint stripping chemicals. So aircraft paint removers do not provide an effective way to dissolve cured expanding foam.

Conclusion

In summary, cured polyurethane expanding foam sealants like Great Stuff cannot be dissolved using common solvents. Once the foam has fully expanded and hardened, the rigid cross-linked polymer matrix prevents any breakdown by solvents. Acetone, alcohols, paint thinner, bleach, and even harsh solvents like gasoline, turpentine, MEK, xylene, and aircraft paint strippers have no effect on curing foam. The complex chemical structure of polyurethane foam simply cannot be broken down once fully cured. Solvents do not provide an effective option for removing or dissolving hardened expanding foam from surfaces.

What does work to remove cured expanding foam?

Since solvents do not work on cured foam, physical removal is the most effective option. Methods like cutting, scraping, sanding, and grinding can be used to mechanically remove the rigid foam. This typically requires tools like a sharp utility knife, chisel, scraper, coarse sandpaper or a rotary tool with a grinding bit. The process is slow, tedious and messy, but necessary for eliminating cured expanding foam. Protective gear like gloves, eye protection and respirators are highly recommended when physically removing foam.

Expanding foam remover spray products are also available, but work primarily through mechanical action. The spray helps soften the foam to make scraping easier but does not truly dissolve the foam. Thermal mechanisms like heating to soften the foam or freezing to make it brittle may also help the physical removal process.

When possible, avoidance is advised. Applying petroleum jelly or tape to surfaces before spraying foam can prevent unwanted adhesion. Dispensing the right amount and trimming the foam before it sets can also minimize issues. But when cured foam must be removed, physical methods are required to eliminate the tough rigid plastic polymer.

Tips for removing cured expanding foam

Here are some useful tips to help tackle the challenge of removing cured expanding foam sealant:

• Use a utility knife with fresh blades to slice away foam a bit at a time
• Scrape with chisels or putty knives, working at an angle parallel to the surface
• Roughen foam with coarse sandpaper before scraping to break up the top layer
• Use a rotary tool with a grinding bit to abrade away stubborn foam
• Apply foam remover spray liberally and allow time to penetrate before scraping
• Wipe away foam dust and residue frequently to keep the area clean
• Go slow to avoid damaging the underlying surface
• Wear appropriate protective gear for safety

Removing cured expanding foam takes patience and elbow grease. But with the right tools and technique, the stubborn foam can be eliminated.

Can you use a solvent to dissolve uncured expanding foam?

For freshly dispensed expanding foam that has not had time to fully cure, solvents can be effective. Uncured polyurethane foam is still undergoing the chemical reaction that causes expansion and hardening. During this soft gel-like phase, strong solvents like acetone, paint thinner, xylene, MEK, or toluene can dissolve and break down the foam.

The key is to apply solvents immediately before the foam cures. Once left to harden fully, the foam’s rigid cross-linked structure prevents dissolution. Quick action with the right solvent can dissolve uncured expanding foam and prevent it from hardening on surfaces.

Safety concerns when trying to dissolve expanding foam

It’s important to keep safety in mind when working with solvents and other methods to try to dissolve expanding foam:

• Wear protective gloves, eyewear, and respiratory gear.
• Work in a well-ventilated area.
• Avoid ignition sources when using flammable solvents.
• Store hazardous chemicals properly in closed containers.
• Dispose of expanding foam and waste solvents appropriately.
• Avoid contact between solvents and skin or eyes.
• Take care when using sharp tools, rotating brushes, or abrasive bits.

Rushing the process or using the wrong methods can also damage the substrate material underneath the foam. Patience and the proper safety precautions are advised when attempting to dissolve and remove cured expanding foam sealant.

Key Takeaways

• Common solvents like acetone, paint thinner, alcohol, and bleach cannot dissolve cured polyurethane expanding foam.
• Once hardened, the foam’s rigid cross-linked structure prevents breakdown from solvents.
• Physical removal methods like cutting, scraping, and abrasion are required to remove cured foam.
• Fresh uncured foam can sometimes be dissolved using aggressive solvents like xylene or MEK.
• Safety gear and proper ventilation are essential when using solvents around expanding foam.
• Patience and the right tools are needed to successfully eliminate cured expanding foam.

Conclusion

Fully cured expanding polyurethane foam sealant cannot be dissolved with common solvents or chemicals. The rigid plastic polymer matrix that forms as the foam hardens is impervious to breakdown from acetone, alcohol, paint thinner, bleach, and even harsh solvents like turpentine or gasoline. Physical removal methods are required to eliminate hardened expanding foam from surfaces. Scraping, cutting, sanding, grinding or specialized expanding foam removers provide the most effective options for dealing with over-applied cured foam. For health and safety, proper protective gear should always be used along with adequate ventilation when attempting to remove cured expanding foam sealant.