pull test equipment in action

Question: “Scott the PAINTER” from California asks: I recently purchased several round base style magnets from the hardware store and they don’t seem to work properly.  I spoke with the folks at the store and they told me there is nothing wrong with them.  They attached them to those orange beams in the store and they worked great.  I am using them on the roof of my car to hold a small sign for my business.  The packaging stated that they would hold 80 pounds.  In the store they felt really strong but when I applied them to the roof of my car it felt like I could pull them off with less then 80 pounds of effort.  Can you explain to me why this is happening?  My car is made of steel.  I have already had one sign blow off and I can’t afford to loose another one, please help.

Answer: Hello Scott,  Thank you for your post.  This is a common issue we have experienced with magnetic assemblies.  When Adams Magnetic Products or any other magnet manufacturer test their assemblies we base the results on a .375″ thick piece of steel (more…)