Galvanic Corrosion and Bike Racks

[Jim and Frances]

I removed our bike rack factory installed 1.5" receiver and noticed some corrosion on the underside of the rack where the u-bolts/washer attach .  Will be checking other fasteners / washers going through the aluminum members around the bumper/bike rack area and adding some thin delrin/acetal washers to put under the stainless washers and maybe adding a thin coat of Ultra Tef-Gel to the hole walls  -OR- should I do something different? 

[Jim and Chris Neuman]

Corrosion between dis-similar metal is common in the boating world.  Very common to find severe corrosion between, say, a 6061 aluminum mast pad  or hardware pedistal and a bronze halyard winch if the two are bolted directly together.  A thin layer of plastic between the two  virtually eliminates this problem, particularly if you use an anti-sieze on bolt (typically stainless) threads.  I use lanolin anti-sieze commonly found in boating stores.  My favorite barrier material is easy and cheap to make.  Prepare a smooth surface with mold release wax, lay a section of a light fiberglass cloth (say an 8 oz) and saturate with a laminating epoxy such as West Systems or System Three.  You now have a sheet of flexible barrier material which can be cut to size as needed.

 

[Jason Foster]

6 hours ago, Jim and Frances said:

I removed our bike rack factory installed 1.5" receiver and noticed some corrosion on the underside of the rack where the u-bolts/washer attach .  Will be checking other fasteners / washers going through the aluminum members around the bumper/bike rack area and adding some thin delrin/acetal washers to put under the stainless washers and maybe adding a thin coat of Ultra Tef-Gel to the hole walls  -OR- should I do something different? 

This is on my to-do list.