I need some thing (1/16") thick pieces on my build so I'm going to use some steel sheet. Can I use regular steel (not galvanized) and prime/paint it or would it still rust? I would think the paint would seal it.
Steel and paint - will it rust?
- Thread starter Sluis Van Shipyards
- Start date
Darth Lars
Master Member
Maybe you cold use automotive primer with built-in rust-protection?
TazMan2000
Master Member
Yes. Automotive paint is best. No guarantees on rust forever, but as long as there are no scratches or inclusions in the paint you should be good.
How are you planning on attaching the steel the steel to your build? You also can us aluminium, which is more corrosion resistant and lighter as well.
TazMan2000
How are you planning on attaching the steel the steel to your build? You also can us aluminium, which is more corrosion resistant and lighter as well.
TazMan2000
I'm not an expert, but if I was doing, this would be my approach. After properly prepping it (remove any corrosion/oxidation) and cleaning it I'd prime with metal etch spray paint. Then I'd go over that with an epoxy enamel spray paint - very durable stuff. Clear coat if you want to.
I'm using aluminum for most, but I need something magnets will attach to, and the area is too thin to embed magnets for a magnet to magnet attachment. So I figured steel would work best. I posted this the other night not even thinking to call my dad. He did custom paint jobs for his Corvettes before I was born so it would be a no brainer. He also said automotive primer, or he said there are separate metal sealers designed to go on before primer/paint.
You need to use an etch primer, which can be found at automotive aftermarket stores. If you just put paint over bare metal, it will scratch off, very easily. The
etch primer, "bites" into the bare metal, than gives your primer, and/or paint something to stick to. Epoxy paints are the best solution, but money, equipment, and
proper preparation are needed. Etch primers in the spray can work pretty good. They are recommended for touching up small area's on vehicle's
but they can be used for prop builds as well, and work fine. you just need to make sure that all rust is removed, and cleaned with a metal prep, or
in the very least lacquer thinner ( but I didn't say that! ). Rust! The cancer for cars, or bare metal. you can clean and prep and metal surface to
perfection, but once it starts, it can have a slight chance to return. I've seen it do weird things, not trying to worry you, but it just does!
Depending on the durability your looking for, and if it's going to be inside, as apposed to outside. You could prep the bare metal with Lacquer thinner ( cheap easy way! )
than use a etch primer, than regular primer, sand smooth, than paint.
It can get difficult to explain proper procedures, in a forum. If anything check your local automotive paint store. Now! if you tell them what you want to do, and they have no
clue what your talking about, just turn around and leave! Paint reps are a dying breed. I know because I am one.
etch primer, "bites" into the bare metal, than gives your primer, and/or paint something to stick to. Epoxy paints are the best solution, but money, equipment, and
proper preparation are needed. Etch primers in the spray can work pretty good. They are recommended for touching up small area's on vehicle's
but they can be used for prop builds as well, and work fine. you just need to make sure that all rust is removed, and cleaned with a metal prep, or
in the very least lacquer thinner ( but I didn't say that! ). Rust! The cancer for cars, or bare metal. you can clean and prep and metal surface to
perfection, but once it starts, it can have a slight chance to return. I've seen it do weird things, not trying to worry you, but it just does!
Depending on the durability your looking for, and if it's going to be inside, as apposed to outside. You could prep the bare metal with Lacquer thinner ( cheap easy way! )
than use a etch primer, than regular primer, sand smooth, than paint.
It can get difficult to explain proper procedures, in a forum. If anything check your local automotive paint store. Now! if you tell them what you want to do, and they have no
clue what your talking about, just turn around and leave! Paint reps are a dying breed. I know because I am one.
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Ok one more question. How does self etching primer effect plastic? I assume if it will etch metal that would be bad. I have one plastic piece I already glued so I'm assuming I will need to mask it.
Dreamscape
Active Member
How strong do you need the magnetism to be and does it need to be metal? Could you use magnetic vinyl sheets on another material instead? Then spray then with a metallic paint.
Ok related question, what do you guys think about having to use etching primer on aluminum? Someone told me you need to, but on some car forums they say if you sanded the aluminum with at least 400 grit, you've already etched it. Obviously you don't have the same problem with rust, even though the aluminum oxidizes. I've always just primed aluminum with regular primer and never had a problem.
sandbagger
Master Member
I used POR-15 on the inside of my Steel Iron Man suit, standard primer and undercoat, spray-putty and paints on the outside. The steel is a normal, low-carbon, mild-steel cold-rolled sheet. It's been a couple of years complete and no rust evident. Here's the link to POR-15. https://www.por15.com/
SB
SB
So does anyone know about aluminum in my last post?
For durability, I would say the etch primer route, would be best.
I got Dupli Color etching primer so I'll give it a try. Does anyone know if aluminum etching primer would work on brass? I don't know what the etching chemical is so no idea.
I could not say for sure. If anything, you could try a small spot, and see if it scratches off. just make sure the surfaces are clean, and do not
have any polish on the surface.
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Typically the etching chemical in most any paint is just an acid that helps clear the surface of the thin oxide that builds up on most metals. Typically a metal primer will work on all metals, as it isn't actually reacting with the metal, but with the oxides on the surface.
Steel: Oxidized somewhat quickly, the good thing is you can see the rust/discoloring. It oxidizes slow enough that you can clean then paint steel even hours later.
Aluminum is actually one of the most reactive metals to oxygen, but the thin oxide layer it builds up on the outside actually protects the rest of the metal. In the case of non-plated aluminum, this oxide layer can be just a few atoms thick, but still very resistant to further corrosion. Any light sanding, or even a scrubbing pad will exposed the underlying un-oxidized layer. However, because it reacts within seconds and builds up a new oxide layer, you typically want to use a etching paint or a primer on Aluminum.
Brass is very slow to oxidize. Like steel you can see the oxidization as a discoloration of the surface. Brass however has a lower coefficient of friction, so mechanical sanding is best before painting.
Plastic Most plastics don't react with acid, and so metal primers don't do anything, and sometimes don't stick well without mechanical etching. Plastic primer/paint typically has acetone or a similar chemical that does react with the base plastic. (Typically geared towards ABS plastic). But there are plastics such as PTFE that don't react at all with acetone and are very hard to paint.
Steel: Oxidized somewhat quickly, the good thing is you can see the rust/discoloring. It oxidizes slow enough that you can clean then paint steel even hours later.
Aluminum is actually one of the most reactive metals to oxygen, but the thin oxide layer it builds up on the outside actually protects the rest of the metal. In the case of non-plated aluminum, this oxide layer can be just a few atoms thick, but still very resistant to further corrosion. Any light sanding, or even a scrubbing pad will exposed the underlying un-oxidized layer. However, because it reacts within seconds and builds up a new oxide layer, you typically want to use a etching paint or a primer on Aluminum.
Brass is very slow to oxidize. Like steel you can see the oxidization as a discoloration of the surface. Brass however has a lower coefficient of friction, so mechanical sanding is best before painting.
Plastic Most plastics don't react with acid, and so metal primers don't do anything, and sometimes don't stick well without mechanical etching. Plastic primer/paint typically has acetone or a similar chemical that does react with the base plastic. (Typically geared towards ABS plastic). But there are plastics such as PTFE that don't react at all with acetone and are very hard to paint.
Thanks!
