Filler and Primer or vice-versa?

Since I've never painted over aluminum before, I'm wondering what the conventional wisdom is regarding what goes on first. I'm thinking Alodine, filler and primer, but would like to hear from those with experience on this. Thanks.

One guide...

szicree said:

Since I've never painted over aluminum before, I'm wondering what the conventional wisdom is regarding what goes on first. I'm thinking Alodine, filler and primer, but would like to hear from those with experience on this. Thanks.

Click to expand...

Steve... this application guide should give some guidelines.
It's for Sterling Paint, but other manufacturer's have similar systems.

http://detcomarine.com/slacguide.htm#AIRCRAFT APPLICATION GUIDE

Detco is close to you in Orange County... they used to give a 40% EAA discount....

The Sterling U-1201 is Mil-Spec epoxy primer...

The "Medium Performance" is close to DuPont's Imron instructions...

Add...

If you prime before filling, then the primer layer will act as a guide so that you don't sand away any of the metal (or Alclad layer) when smoothing out the filler...

gil in Tucson

my experience

is that filler sticks much better to an epoxy primed surface than bare metal. of course alumna preped and alodined first. YMMV but i like the epoxy under neath to prevent corrosion and bonding issues.

added
if you fill over etching primer ,,let it dry for a day or two. seems the etching agent will causes issues with the filler.