Problems encountered with metal adhesive are often not caused by the glue itself, but rather because of a poorly treated surface to which it simply ‘doesn’t stick’. Adhesives do not adhere well onto oils, oxidation and dust which may be present on many surface areas. It also does not work best with smooth finishes of surfaces. Some preparation in advance can be the difference between something that gets fixed in one application, and a longer term bond.
Inspect the Surface and Adaptation
This needs to be done before you start, that the parts fit tightly and do not move during curing. With wide gaps, unless you’re using a gap-filling product, adhesive can really struggle to do its thing. For Metal bonding adhesive, visit https://www.ct1.com/product-applications/metal-to-metal-adhesive
Clean Dirt and Loose Debris
Dust, rust flakes and grime can be wiped off only with the aid of a clean cloth. A gentle wash in warm soapy water is recommended first followed by thorough drying.
Sand to create grip
Rough surfaces allow metal–metal bonding for most metals.
Medium grit sandpaper (80–120 grit) for a good “key”.
Criss-cross the surface with sand instead of polishing in one direction.
Gradually remove the majority of most remaining material, you want a dull lightly scratched surface instead anyof thing gorging deep.
Degrease properly
Polishing products and machining can leave unseen oils on metal that looks clean. A separate degreaser or isopropyl alcohol on a suitable lint-free cloth is recommended.
Rub once, then use a fresh part of the cloth and rub again.
Allow for the alcohol to fully evaporate before applying adhesive.
Pro tip: you just prepped and are ready to go – do not touch it with your naked fingers, because skin oils undo your hard work.