phishtaco
Cincinnati
I've got some Hanna Quality sliders on my 4Runner and the powdercoat is peeling off in places. Do I have to bring theses down to bare metal to recoat with rattle can? Can I just peel off the loose sections, sand, prime, paint?
Painting over powdercoated sliders
- Thread starter phishtaco
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Hi phishtaco,
I've just made an account so I can hopefully answer your question properly.
Simple answers: Yes. Maybe.
Detailed answer: You should remove any remaining powder coating if you plan on applying spray paint over these. Your finish coat is only as strong as what's underneath it. Surface preparation is the most important step when painting.
When your sliders were initially powder coated, they *should* have been abrasive blasted to at least an SSPC-SP6 Commercial Blast. If not, then they were more than likely mechanically abraded with hand or power tools (wire wheel, power sanding etc.). This is to create a 1.0-1.5 mill angular anchor profile for the powder coating to adhere to. If the old coating is peeling off, it needs to come off, this is a failing system and it will all eventually fall off depending on weathering and abrasion.
Powder coating goes on relatively thin at around 6.0-10.0 (or 0.0006-0.0010 of an inch) mils DFT (Dry Film Thickness) and it's only 1 coat.
Spray paint is applied around 0.5-1.5 mils DFT. For example a Krylon acrylic alkyd enamel in a spray can if applied at 3.0 mils wet will end up with 1.0-1.5 mils dry. These are low solids paints and not very strong overall. Obviously you can build this up with multiple coats for better protection but it's not going to be great, a short-term fix if you will.
If I were you I would want a paint system that would last, be a rust/corrosion inhibitor and have UV protection. That means sanding these down to bare steel using first a wire wheel then some 120 grit or coarser sand paper to achieve a profile.
I would then apply 2 coats by roller of a Hi-Build high solids epoxy for rust and corrosion protection then 2 coats by roller of a high solids polyurethane for gloss retention and UV protection. Epoxies chalk and yellow when exposed to UV for a long period of time. Each epoxy coat if applied with those foam rollers from ACE/Walmart will give you around 4.0-5.0 mils DFT depending on your application skills. Each polyurethane coat will give you 2.5-3.5 mils DFT. So you are looking at a 13-19 mils DFT for your final thickness, even more if you go slow and apply nice even thick coats. You could do 3 coats of the epoxy primer if you want for even more protection against rocks and what not.
This is a nice system that would allow of easy touch up (unlike powder coating), is strong strong + reliable (unlike spray paint), and will look good for years to come.
Now this isn't going to protect your steel from when you slam into a rock going 15 MPH, but nothing will do that. When you do end up scraping up the coating it is simple to fix.. Simply sand down to epoxy, apply 1 coat, then your 2 finish coats of urethane!
Sorry if this is too much, but it's something to think about. My girl and I just did this to her Tacoma (finally) over the last 2 weekends and it looks amazing! Here is an album http://imgur.com/a/2Fw1W . I uploaded it backwards but oh well. Bottom pic is of the primer already applied. Top pic is her applying polyurethane top coat so you can see the color difference. Yeah, she likes green... Then there's 2 more I think and 1 of me mixing before painting.
Source: I am a coating consultant...
Feel free to ask questions if you're curious, if not HEY! I had fun typing this up.
I've just made an account so I can hopefully answer your question properly.
Simple answers: Yes. Maybe.
Detailed answer: You should remove any remaining powder coating if you plan on applying spray paint over these. Your finish coat is only as strong as what's underneath it. Surface preparation is the most important step when painting.
When your sliders were initially powder coated, they *should* have been abrasive blasted to at least an SSPC-SP6 Commercial Blast. If not, then they were more than likely mechanically abraded with hand or power tools (wire wheel, power sanding etc.). This is to create a 1.0-1.5 mill angular anchor profile for the powder coating to adhere to. If the old coating is peeling off, it needs to come off, this is a failing system and it will all eventually fall off depending on weathering and abrasion.
Powder coating goes on relatively thin at around 6.0-10.0 (or 0.0006-0.0010 of an inch) mils DFT (Dry Film Thickness) and it's only 1 coat.
Spray paint is applied around 0.5-1.5 mils DFT. For example a Krylon acrylic alkyd enamel in a spray can if applied at 3.0 mils wet will end up with 1.0-1.5 mils dry. These are low solids paints and not very strong overall. Obviously you can build this up with multiple coats for better protection but it's not going to be great, a short-term fix if you will.
If I were you I would want a paint system that would last, be a rust/corrosion inhibitor and have UV protection. That means sanding these down to bare steel using first a wire wheel then some 120 grit or coarser sand paper to achieve a profile.
I would then apply 2 coats by roller of a Hi-Build high solids epoxy for rust and corrosion protection then 2 coats by roller of a high solids polyurethane for gloss retention and UV protection. Epoxies chalk and yellow when exposed to UV for a long period of time. Each epoxy coat if applied with those foam rollers from ACE/Walmart will give you around 4.0-5.0 mils DFT depending on your application skills. Each polyurethane coat will give you 2.5-3.5 mils DFT. So you are looking at a 13-19 mils DFT for your final thickness, even more if you go slow and apply nice even thick coats. You could do 3 coats of the epoxy primer if you want for even more protection against rocks and what not.
This is a nice system that would allow of easy touch up (unlike powder coating), is strong strong + reliable (unlike spray paint), and will look good for years to come.
Now this isn't going to protect your steel from when you slam into a rock going 15 MPH, but nothing will do that. When you do end up scraping up the coating it is simple to fix.. Simply sand down to epoxy, apply 1 coat, then your 2 finish coats of urethane!
Sorry if this is too much, but it's something to think about. My girl and I just did this to her Tacoma (finally) over the last 2 weekends and it looks amazing! Here is an album http://imgur.com/a/2Fw1W . I uploaded it backwards but oh well. Bottom pic is of the primer already applied. Top pic is her applying polyurethane top coat so you can see the color difference. Yeah, she likes green... Then there's 2 more I think and 1 of me mixing before painting.
Source: I am a coating consultant...
Feel free to ask questions if you're curious, if not HEY! I had fun typing this up.
Benwah, that's good info there!
