Stainless steel, or “inox steel” is a steel alloy containing chromium. It does not corrode, rust, or stain like normal steel. It normally is quite easy to bond and does not require much in the way of surface preparation; however, mirror-finish stainless steel can have very low surface energy and prove difficult to bond.
Providing you are not dealing with a mirror finish, the following adhesive types bond stainless steel:
Anaerobic adhesives – threadlockers, thread sealants, form-in-place gaskets, and retaining compounds all work well on stainless steel. However, it is important to note that stainless steel is a fairly inactive metal, so the anaerobic adhesives will develop strength more slowly than the steel fixture times noted on the data sheets. Special grades which cure faster on stainless include; HM163 retaining compound, HM135 threadlocker, and LH150 pipe sealant.
Cyanoacrylate adhesives – all grades bond, but special grades for metals form the strongest bonds. Permabond 910 is the original pure methyl cyanoacrylate for metal bonding.
Structural adhesives like one component heat cure epoxies, two component epoxies, and structural acrylics bond very well – again, providing the surface isn’t super smooth. For highest bond strength, contact Permabond for a specialty stainless steel bonding adhesives.
Or see our new stainless steel bonding grades here.
UV curable adhesives also bond stainless steel, providing the second substrate permits UV light to pass through. Metal to glass grades include; UV610, UV620, UV625, UV670 and UV7141.
Often you can bond stainless steel as received. However, degrease with isopropanol, or Permabond Cleaner A to remove contamination. Do not use white spirit, turpentine, etc… as these may leave a residue. Ensure the solvent is fully evaporated before attempting to bond.
Roughening the stainless steel surface improves adhesion and durability. However, stainless steel is very hard, so abrading the surface with sandpaper, scotch brite, or steel wool is not easy.
Automated means of abrading the surface can generate heat which might cause a surface change, decreasing the adhesion of adhesives to the stainless steel. To avoid heat generation, sandblasting is recommended.