Thanks, Jeff.  I appreciate the recommendation.

The reason I would prefer not to use rubber as a spacer is I want to use
the P strap for grounding the sender.  Having to ground it with the
rubber in place would further complicate the installation.

Mike

Kjmmensing@aol.com wrote:
> Maybe  in the chain link fence dept at Home Depot.
> You might even go 1 1/2 " and use some rubber between
> ( red 1/8 " thick sheets available in the plumbing dept.)