When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
<cr>
Great question. I don't have the answer though. My suggestion is that you contact the ZR people via their web site.
Personally, I was going to give it a try in a few weeks, on some non-critical areas, in my engine compartment. If it didn't work, I hadn't lost anything.
Having already purchased the Zerorust, I contacted the company as suggested. FYI, they never responded to my question. They have lost me as a customer.
<cr>
Well, we got the official answer and in the short form it's, yes, you can apply filler over the top of ZR.
You must allow a complete drying of ZR before the filler is applied. Two weeks dry time is recommended. After the prescribed drying period, apply a good scratch (I would recommend 80 grit) to the ZR before the filler is applied.