>80 grit on bare metal before epoxy

E

erover82

Promoted Users
If the goal is to remove all oxide and give a scuff, will finer grits than 80 also provide good adhesion on smooth bare metal panel? It seems odd that it wouldn't considering that Alodine'd aluminum and 400 grit sanded e-coat are apparently (from my understanding) sufficient for epoxy adhesion.

Context:
This is a classic 4x4. Panels are mostly brand new, either HDG steel or aluminum. They'll never be straight or stay that way for long, so filler and block sanding are pointless. I don't want high-gloss. I want to go straight to SS solid-color urethane after epoxy without having to fill in 80 scratches.
 
Last edited:
erover82 said:
If the goal is to remove all oxide and give a scuff, will finer grits than 80 also provide good adhesion on smooth bare metal panel? It seems odd that it wouldn't considering that Alodine'd aluminum and 400 grit sanded e-coat are apparently (from my understanding) sufficient for epoxy adhesion.

Context:
This is a classic 4x4. Panels are mostly brand new, either HDG steel or aluminum. They'll never be straight or stay that way for long, so filler and block sanding are pointless. I don't want high-gloss. I want to go straight to SS solid-color urethane after epoxy without having to fill in 80 scratches.
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Yes, but the first step for Alodine is an acid treatment due to all the rivets.
And you are applying epoxy over the alodine a must do for last 45 years.

Without this treatment, anything finer than 80 over bare metal will be a risk and could reduce aadhesion
 
Thanks, I'll stick to 80 on steel and galv

On softer metals like Aluminum 80 will dig deeper, in that case is 120 good, or still stick to 80?
 
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