Glass Reinforced Filler

[Joe in NY]

I have a couple of small areas where I was planning to use some glass reinforced filler. I seem to recall reading that it is advisable to apply this kind of filler directly to bare metal as opposed to applying epoxy first. What's the best approach here?

 

[RenewAP]

It is better to have all the metal coated with 2 coats of unreduced epoxy, then use fillers over the epoxy after it has cured. This will give you an unbroken seal over the panel for best adhesion and corrosion protection. I put fillers directly on the metal for years with very few issues, but did find a few times when I had to do a repair years later that rust would be under my filler. I haven't had that since doing the epoxy first.

 

[dhutton01]

Always apply filler over epoxy in the recoat window per the TDS….