How to paint metal
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  1. #1
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    Default How to paint metal

    Howdy. New here but hoping to get some advice!

    Iíve been doing some metal fabrication as a hobby for a while but I still have terrible luck with painting.

    Iíve tried following the steps Iíve been told/seen (thorough cleaning, sanding, primer) but I always have issues with the paint sticking. Even after weeks or month (to harsh a bump with something and it comes off)

    Any help would be greatly appreciated!

    Thanks in advance.

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    More info needed - like material and condition - bright black etc etc etc.

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    Quote Originally Posted by Hdmcclx View Post
    Howdy. New here but hoping to get some advice!

    Iíve been doing some metal fabrication as a hobby for a while but I still have terrible luck with painting.

    Iíve tried following the steps Iíve been told/seen (thorough cleaning, sanding, primer) but I always have issues with the paint sticking. Even after weeks or month (to harsh a bump with something and it comes off)

    Any help would be greatly appreciated!

    Thanks in advance.
    Home Page - Projects and Articles on Our Forum! | The Hobby-Machinist several GREAT ! articles on what your attempting.

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    if it was easy, everybody would be doing it.

    aluminum is slipperier than snot, and never keeps its paint on, for very long.

    Steel really likes it best if you sandblast it first, then prime and paint right away.

    powdercoating is a good trick, and you dont have to clean the brushes, but you pay for it. Also, in the long term, (ie, 5 to 15 years, depending on environment) powdercoating always fails. And then, its a big mess, as most sandblasters wont even take your money to get it off, as it peels like a bad sunburn in some places, and sticks for eternity in others.

    Good paint really helps.
    Real oil or alkyd based enamels, like Rustoleum, or One Shot, will outlast any water based paint ever made.

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    The catalyst activated auto paint is the only thing I have found that holds up well. Very pricey but it does stay put. The obvious things still apply. Very clean surface , proper primer etc.

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    sand
    clean
    prime
    top coat

    If the paint comes off it wasn't clean

    Aluminum will hold paint but you need to prime it within 15 minutes of sanding it


    because someone is a beginner does not make them a hobbyist

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    Nothing that is painted holds up well unless it is well protected (not touched, kept indoors, and away from chemicals, UV light, etc.)

    That's why powdercoating and other coatings have arisen. Even powdercoating has become a crap shoot....it can be, and is often, done poorly and fails to hold up.

    I enjoy making stuff... I hate applying finishes to them.

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    You haven't said what material, how fine a finish you want, or typical use. A hard bump will take most paints off a surface with the possible exception of moisture cure polyurethane over a sandblasted or phosphated steel base.

    Aluminum should be cleaned with caustic and treated with alodyne for best paint adhesion.

    For ruggedness consider automotive coatings such as chip guard or truck bed liner. The last is very resistant to chipping, and comes in many colors. Even the chip guard that comes in spray cans is pretty durable. I used to use it on the bottom and corners of steel tool boxes to reduce paint damage.

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    If you are just using a rattle can then...

    Use a spray gun with two part primers and paints. I use DuPont industrial coatings. It is used for painting metal that is outdoors like pipes, water towers, etc.
    It is less expensive than automotive paint but I have finishes looking like glass.
    Have to use a clean air system with a breathing mask and take precautions with gloves.

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    Until you fess up to what kind of paint you were using, its all just a guess as to why you have not been happy with the results.

    Never bothered with primer on anything of a utility nature, went straight to Tremclad rust paint or POR.

    If you want to paint aluminum, find a self etching primer. We were specifically prevented from using the stuff on aircraft parts because the only ways to get it off the metal, were destructive.

    Buy proper paint, from a real supplier, rather than a hardware store, if possible. Some place that deals in automotive, industrial, or aircraft finishes. Expect it to be expensive.

    Clean the project before painting.

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    Quote Originally Posted by Hdmcclx View Post
    Howdy. New here but hoping to get some advice!

    Iíve been doing some metal fabrication as a hobby for a while but I still have terrible luck with painting.

    Iíve tried following the steps Iíve been told/seen (thorough cleaning, sanding, primer) but I always have issues with the paint sticking. Even after weeks or month (to harsh a bump with something and it comes off)

    Any help would be greatly appreciated!

    Thanks in advance.
    It is fairly simple. Paint will only stick to metal if it is clean and has high surface energy. Something like etching, sanding, media blasting and high temperature oxides give high surface energies. Simple way to know you have high energy is that the surface will wet with water. If water in any way beads or runs off, you are not there and paint will not stick. Near all solvents leave a residue which is counter productive. Surface energy is highly time sensitive and will disappear from the surface molecules in a matter of hours. So immediate painting is required. Primer is optional, depending on your particular needs.

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    i shot at my target and missed. what did i do wrong? hahaha

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    Quote Originally Posted by cg285 View Post
    i shot at my target and missed. what did i do wrong? hahaha
    Forgot to unzip....

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    Quote Originally Posted by cg285 View Post
    i shot at my target and missed. what did i do wrong? hahaha
    Paint your steel plates.

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    Me thinks the Op needs to stick with the "Watching it dry" part....
    and stay away from the fumes too.

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    Quote Originally Posted by Hdmcclx View Post
    Any help would be greatly appreciated!
    I have stripped paint off of metal and underneath is just brown rust. Rust from within. So it is important to clean the metal first.
    Whatever is the method I do a final wipe with some DuPont lacquer and enamel cleaner 3939S.

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    Artists supply or equivalent for good brushes. I paid $15 for one brush and it was on sale from $35.
    1 & 1/2 width and 3/8 thick.
    Prime with the same quality as the finish brush.
    It is like sending parts out for chrome plate. All defects will show up in the finish.

    file://localhost/Users/wrickfaris/Desktop/Misc.%20Files%20&%20Photos/OWWM%20Paint%20Thread/High%20Quality%20Brush%20Painting.htm

    The above link will take you to " High Quality Brush Painting " ........a pdf file to download about163kb in size.
    Copy and paste into your browser.

    Finish coat was applied in December at about 50 degrees temp.
    science-project.jpgsilver-drill-base.jpgsilver-drill.jpg
    John

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    Try powder coat, failing that; consult PPG and or see what other blokes have done.
    Or possibly anodize.

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    We have in house powder coating at a small scale and just sand blast everything first. The powder coat never fails though even then you need outdoor paint for outdoor applications. (Ask me how I know.) But this a professional site so I suggest doing what I do and sent your larger metal hobby projects out to pro powdercoating places. They do a chemical etch as it's more efficient than sand blasting but it's the same surface energy idea?

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    Quote Originally Posted by Scottl View Post
    You haven't said what material, how fine a finish you want, or typical use. A hard bump will take most paints off a surface with the possible exception of moisture cure polyurethane over a sandblasted or phosphated steel base.

    Aluminum should be cleaned with caustic and treated with alodyne for best paint adhesion.

    For ruggedness consider automotive coatings such as chip guard or truck bed liner. The last is very resistant to chipping, and comes in many colors. Even the chip guard that comes in spray cans is pretty durable. I used to use it on the bottom and corners of steel tool boxes to reduce paint damage.
    can you get alodyne (e.g. alodyne 600) online?


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