Bondo on bare metal, or primer first?

[dremu]

Yeah, I know, I should prolly read the can... but.

I have some fairly shallow dings to fill in (~1/8", not bad at all), so I'm wondering if I should wirebrush the area, then primer it ... or just wirebrush it, then Bondo and sand until flat.

Any takers?

-- A

 

[tx_sub]

you can do either. i work in a welding shop. in the finishing dept they do it both ways. if it shows up after primer, sand and bondo adn resand. we use the same bondo with the picture of the car on it. it works fine on surfaces but not corneers. its too soft for that and will chip. lay it on thicker than you need and sand it flush. good luck.

 

[ryoken]

wire brushing is not the way to go usually... burnishs and sheens it too much.. you want an etch to it... grinder with 24 to 36 grit... 2" Rolocs work well for nooks and crannies...

your not supposed to bondo over primer. tho sand scratchs and very minor dings can be taken care of after priming with a glazing putty..

if your concerned about corrosion you can put a light coat of zinc chromate over the bare metal before bondo.. it is thin enough to not mess with the etch from the grinder...

 

[JK5]

PPG recommends using DP primers on bare metal..
before you mud..to keep moisture off the steel..

But if you are just using rattle cans..
Mud over bare metal..because rattle can primer..
doesn't adhere as well as epoxy..

Wire brushes...make metal to smooth fo good adhesion..
I use #36 grit 5" disks on a hand grinder..
They make attachments that make it possible to use a drill.
to grind.

Have Fun..