Hairline, spider-web cracks radiating outward. 3. Low Humidity on the Substrate Polyurethane is moisture-cured. If you apply Devfus foam to bone-dry, dusty, or frozen substrates, the foam cannot cure properly. The surface skins over, but the interior remains tacky. As the foam eventually attempts to draw moisture from the air, uneven curing creates fissures.
Chalking surface, with cracks only on the sun-exposed side. 5. Movement of the Substrate Devfus foam is flexible but not elastic like silicone. If you apply it across a dynamic joint (e.g., between two wood studs that expand/contract with seasonal humidity), the foam will eventually tear. This is a shear crack . Devfus foam crack
Shake the Devfus can vigorously for 60 seconds. Insert the straw deep into the crack. Apply foam slowly, filling only 40% of the void—remember that foam expands to fill the rest. Overfilling will cause another crack. Hairline, spider-web cracks radiating outward
Spray the area with Devfus foam cleaner or acetone. Wipe with a lint-free cloth. Allow 10 minutes to dry. If you apply Devfus foam to bone-dry, dusty,