Prepping Steel for Painting
- Thread starter thejimmy
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sberry
Banned
Neither, we use epoxy primer similar to Corlar. Have never used one of the others.
Slednut
Well-known member
Yep, epoxy primer and you want to put the finish coats on in the epoxies window so you can get a good chemical bond.
If you wait too long you will have to scuff the epoxy, some epoxies have a 4-5 day window.
If you wait too long you will have to scuff the epoxy, some epoxies have a 4-5 day window.
Jazz1
Well-known member
Always epoxy primer as it gives you plenty time to get around to the finishing paint.
ez-duzit
Well-known member
Sand blast immediately before priming.
Shiftless
Well-known member
if you’re equipped to do this, it’s the very best way to go.
The sandblasted surface with the micro pitting is perfect for adhesion of the primer.
Los_Control
Well-known member
Just curious what you are painting ... "bed sides"
Take what I say with a grain of salt. I am not a painter and asking questions and learning like yourself.
Bed sides to me sounds like a truck ... or could be a arts & crafts project like metal bed frames to be put in the garden.
This really matters as to what quality of paint to use.
Ospho is good for converting rusted metal to a paintable primer.
If you have a metal fence with some rust on it, you want to paint it, use ospho. You can paint over it and will last for a period of time longer, then if you just paint over rust.
While there are a lot of professional painters here ... some get carried away.
While we have nice quality paint available today at a quality price ... we really need to choose the right quality for the project.
Here is a photo of my project. The "bed sides" is treated with phosphoric acid and we guess the rust is neutralized. I am using $30 per gallon Rustoleum primer and paint from tractor supply.
I want to point out the firewall, it is dirty and will clean up ... it is original 70 year old enamel paint applied direct to metal with no primer.
Just saying paint has been around for a long time ... it is better today then it was 70 years ago ...What quality do you want?
Take what I say with a grain of salt. I am not a painter and asking questions and learning like yourself.
Bed sides to me sounds like a truck ... or could be a arts & crafts project like metal bed frames to be put in the garden.
This really matters as to what quality of paint to use.
Ospho is good for converting rusted metal to a paintable primer.
If you have a metal fence with some rust on it, you want to paint it, use ospho. You can paint over it and will last for a period of time longer, then if you just paint over rust.
While there are a lot of professional painters here ... some get carried away.
While we have nice quality paint available today at a quality price ... we really need to choose the right quality for the project.
Here is a photo of my project. The "bed sides" is treated with phosphoric acid and we guess the rust is neutralized. I am using $30 per gallon Rustoleum primer and paint from tractor supply.
I want to point out the firewall, it is dirty and will clean up ... it is original 70 year old enamel paint applied direct to metal with no primer.
Just saying paint has been around for a long time ... it is better today then it was 70 years ago ...What quality do you want?
Attachments
Epoxy is out for me... I've seen too much at work crack and peel in large sheets. Its now no longer in use due how toxic it is for anyone is the area of it being applied. YMMV.
I use a rust converter primer by RustCheck... probably very similar to this ospho already suggested. That's after de-scaling, wire brush, wire wheel, etc. Topcoat with whatever enamel, but usually Tremclad/Rustoleum.
I have used POR15 on parts... very nice. I just don't like the price, and how easy it is to lose the remainder of a can if you don't use it all in short order.
I use a rust converter primer by RustCheck... probably very similar to this ospho already suggested. That's after de-scaling, wire brush, wire wheel, etc. Topcoat with whatever enamel, but usually Tremclad/Rustoleum.
I have used POR15 on parts... very nice. I just don't like the price, and how easy it is to lose the remainder of a can if you don't use it all in short order.
Hack Fabrication
Banned
Give this guy a call: http://www.epoxyproducts.com/ He's very informative. I ordered some single stage paint from him, and delivery was excellent. Product went on easy.
But to get back to your original question, prep is key to a good paint job. Depending on the quality of steel, whether it is hot or cold rolled, and how much weather it's seen. If blasting is out of the question, be prepared to spend some quality time with a wire brush. Both hand and power. Then some sanding. Then some sort of converter or rusty metal primer. Then you can think about top coating.
But to get back to your original question, prep is key to a good paint job. Depending on the quality of steel, whether it is hot or cold rolled, and how much weather it's seen. If blasting is out of the question, be prepared to spend some quality time with a wire brush. Both hand and power. Then some sanding. Then some sort of converter or rusty metal primer. Then you can think about top coating.
ez-duzit
Well-known member
Lots of people don't have sand blasting equipment, but somehow manage to get the job done properly anyway by hiring it done.
theoldwizard1
Well-known member
Sand/sandblast. Clean with solvent. Some paints (like Imron) require unique cleaners.
Rust converters are great especially if the steel is not "perfect".
Self etching primer works well also. If you are looking for that perfect "glass smooth" finish, follow with a filler primer. Then a "guide coat" and more sanding
Rust converters are great especially if the steel is not "perfect".
Self etching primer works well also. If you are looking for that perfect "glass smooth" finish, follow with a filler primer. Then a "guide coat" and more sanding
sberry
Banned
I have painted gallons of Imron, sometimes in the same day. I never use any pre treat and very rarely use self etch. If I want it to last it's epoxy primer with Imron on top.
Here is the thing about blast,,, and etch primers are the worst actually,,, but blast leaves peaks and valleys. The valleys not a problem but an etch higher than about 220,,, or blasted has peaks and if a guy looks with a glass or scuffs it off can see the primer run right off and see peaks poking thru, clean thru.
So, sandblast and scuff a couple passes with a maroon brute, it cleans the sand and smooths off the peaks, feel the difference, makes it last. Blow dust off and spray.
The thinners are specific to Corlar and Imron.
Here is the thing about blast,,, and etch primers are the worst actually,,, but blast leaves peaks and valleys. The valleys not a problem but an etch higher than about 220,,, or blasted has peaks and if a guy looks with a glass or scuffs it off can see the primer run right off and see peaks poking thru, clean thru.
So, sandblast and scuff a couple passes with a maroon brute, it cleans the sand and smooths off the peaks, feel the difference, makes it last. Blow dust off and spray.
The thinners are specific to Corlar and Imron.
sberry
Banned
They actually have a couple flavors,, and colors of Corlar but they don't all require blast, they do want rust tightly adhered and a 220 etch.
Clean with solvent if it needs it before blast, I even wash my hands regular after blast, I never want to get anything on it after, none of that stuff, that's **** is for use on unblasted steel. .
Clean with solvent if it needs it before blast, I even wash my hands regular after blast, I never want to get anything on it after, none of that stuff, that's **** is for use on unblasted steel. .
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matt_i
Well-known member
I'm a fan of hitting the metal object with 60 grit, just hand sheets for a light scuffing all over in a couple directions, sort of a cross-hatched pattern like you'd find on the brand new surfaces of an internal combustion cylinder block's bore walls.
Its doesn't telegraph thru the paint and seems to help provide some places to stick.
Sandblasting is better at creating the depth, and more uniform, for sure, but sometimes not as practical as the sanding sheets.
Its doesn't telegraph thru the paint and seems to help provide some places to stick.
Sandblasting is better at creating the depth, and more uniform, for sure, but sometimes not as practical as the sanding sheets.
sberry
Banned
That kind of stuff usually gets brush on enamel. This other **** is to expensive and time consuming, it's for long service life x time x money where prep and labor hi, trucks, airplanes, some equipment.