I took the rear bumper apart on my 1978 Holiday 88 to get it rechromed.

There is rust on the back side of the bumper (see pics).

How should I treat this? I’m planning to use a wire wheel and then some POR-15

Also, I assume I should do this BEFORE I bring it in to be rechromed?

Thanks for your help

 

I would wait until the chrome is redone. Chrome is a chemical process and any coating you put on the bumper could be damaged.

 

Once you get the bumper back from the chrome shop, lightly scuff the backside with a 3M scotchbrite pad and spray a coat of Rustoleum industrial paint to seal it from the elements.

 

I would research finding a less crunchy core before spending the money it takes for replating. Platers might say the same.

 

My usual practice is to lightly sandblast the backside, to check for integrity, before going to the plater. Some times, the rust is too severe, and will have pinholes, or bee too thin for the plater to do a good polish on them before starting.

 

I would have the back media blasted prior to re-chroming, Then after re- chroming apply paint to the back of the bumper.You will know what condition the bumpers are in after media blasting, a few small pin holes can be welded but if its Swiss Cheese you will need new cores This is basically what others have said as well.