sanding/painting
Thread Starter
Registered User
Joined: Mar 2002
Posts: 122
From: Brandon, FL, USA
sanding/painting
I recently sanded down a new fender to put on my car and just primered it, and someone mentioned to me that I should have "roughened up" the metal or something like that before I primered it so that it would hold the primer/paint.. Does anyone know anything about this? I haven't heard/seen anything like that before... TIA!
Registered User
Joined: Oct 2001
Posts: 742
From: Owego, New York
The sanding should have done all the roughing up that it needs...that is basically what people mean by that....just sand it with a course sandpaper or such and it allows the paint/primer to adhere better...you should be all set if you sanded down the whole fender
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Joined: Jul 2002
Posts: 454
From: None
first off is the fender metal or a plastic/fiberglass of some sort?
They sell scuff pads @ autobody stores and chain stores, first you scuff the fender up depending on the condition and material, if its a brand new METAL fender an it has some sort of protective coat then use a RED scuff pad (its more coarse then the grey) if its an old fender with some rust get it soda/sand/bead blasted hit it with a wire wheel, if its plastic use a grey scuff pad its less abrasive then wipe it off with a degreaser and soap an water after wipe it down good, then prime it up, after its primed used a 320 grit wet sandpaper make sure to avoid all edges hit them maybe once or 2x lightly, just wetsand to get it nice an smooth, paint it
They sell scuff pads @ autobody stores and chain stores, first you scuff the fender up depending on the condition and material, if its a brand new METAL fender an it has some sort of protective coat then use a RED scuff pad (its more coarse then the grey) if its an old fender with some rust get it soda/sand/bead blasted hit it with a wire wheel, if its plastic use a grey scuff pad its less abrasive then wipe it off with a degreaser and soap an water after wipe it down good, then prime it up, after its primed used a 320 grit wet sandpaper make sure to avoid all edges hit them maybe once or 2x lightly, just wetsand to get it nice an smooth, paint it
Thread Starter
Registered User
Joined: Mar 2002
Posts: 122
From: Brandon, FL, USA
Ok, thanks CeeBee..
Also, its a regular metal fender.. it seems to be fine right now, but the first time I started putting primer on it it was coming off when I ran my finger over it (when it was dry) but the 2nd can of primer I put on (just to catch some places I missed with first can) it seems to hold fine.. dunno, maybe bad can of primer?
Also, its a regular metal fender.. it seems to be fine right now, but the first time I started putting primer on it it was coming off when I ran my finger over it (when it was dry) but the 2nd can of primer I put on (just to catch some places I missed with first can) it seems to hold fine.. dunno, maybe bad can of primer?
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Joined: May 2002
Posts: 265
From: Goshen, IN
Bare metal requires special primers. If your fender had alot of bare metal spots you would have needed to prime it with a 'self-etching' primer. A self-etching primer has an acid content that helps bite into the metal to help adhesion, and also inhibit oxidation of the metal. Then a coat of sealer should be applied ontop of that (after a thorough sanding with 400 grit) Then it would be ready for paint.
Regular primer will continue to flake off of bare metal. The second tim you sprayed it and it didn't flake just means you had enough mils on it to have a firm surface. Doesn't meant it still will not chip and flake over time.
Regular primer will continue to flake off of bare metal. The second tim you sprayed it and it didn't flake just means you had enough mils on it to have a firm surface. Doesn't meant it still will not chip and flake over time.