Preserve the Beauty of Raw or Rusted Steel & Iron Surfaces

Picture of Preserve the Beauty of Raw or Rusted Steel & Iron Surfaces
I see many ibles made with black pipe here but rarely do they mention any coatings to prevent rusting. I also often build with rusty items where I need to cover the rust so it won't rub of on clothes etc. but don't want to lose the beauty of the patina. An architect once told me he used linseed oil to preserve rusted iron outdoors. I tried it but the damned stuff never fully dries! I could use polyurethane but the oxidation will continue underneath and it will eventually flake off. I've tried "rust stabilizers" but they turn the rust black so it loses it's color. I finally got turned on to a product from an old timer in a paint store I would probably never have found on my own.
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Step 1: Penetrol

Picture of Penetrol
He recommended a product called Penetrol normally used as a paint additive to improve flow and adhesion that also seals and stops rust. It can be used alone as a base coat on bare metal and will fix the rust while preserving the appearance. The finish will be darker than dry rust but similar to rust sprayed with water or oil and can be top coated with a polyurethane for a more durable finish.
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vzdz6 days ago

Hi Brian,

I built a steel fire pit for a client with the intention of letting it rust and sealing it to preserve that rusted color. Well, It's sat in the salty coastal air for a year and the color and texture are now perfect. I'd like to use the Penetrol method, but my question is, will poly be a durable and uv stable enough top coat? I've read that automotive clear coat works real well, too. Any thoughts?

BrianJewett (author)  vzdz6 days ago
If it's fairly heavy steel, I'd just leave it raw. I don't have any outdoor experience as my pieces have all been indoors, but I don't think the coatings will do well with fire. I think someone else hear said it needed re-coating after a year or so outdoors. The rust will scale over, slow down and get even better looking with age. If it's 1/8 inch or better I'd say leave it alone. It will probably outlast your client as is.
skaphan2 months ago

I have some exterior steel doors and trim at my house that is (deliberately!) rusted and that we occasionally coat with Penetrol. The problem is the Penetrol wears off after awhile and then the rusting process starts up again. If you don't stay on top of it it starts scaling and looks bad. Do you think polyurethane would make sense for an exterior application? I'm thinking it might be better to just recoat it with Penetrol every couple of years. I'd hate to have to try to remove polyurethane to refinish it. Or maybe we should use some other type of clear mat coating other than polyurethane?

I have tried many finishes for steel, interior and exterior, and the best i have found is a combination of Penitrol, Carnuba Wax, boiled linseed oil and a little bit of mineral turpentine.

BrianJewett (author)  steamjunkprops2 months ago
Combined how and in what proportions?

Has this worked well in outdoor applications?
BrianJewett (author)  skaphan2 months ago
I haven't tried an exterior application with poly on metal but I haven't had good long term success on wood. I'd try checking with a paint expert. Not at home depot but a good pro store like a Sherwin Williams. If you get a good answer, post it here and share with the rest of us.
crob13 months ago

Hi Brian,

really like the work you did. The info about the penetrol was very helpful. I have an old military metal (fire proof) dresser that i grinded down to get some of the old paint and damaged spots off of it. I messed up and tried a polycrylic on it, but it was a disaster. I removed teh polycrylic, and now I am stuck deciding which polyurthane to use. I dont have sprayer and what wondering if you thought the rustoleum spray poly could be a good choice. they say they have one that goes on metal as well as wood. do you think that would work?

many thanks


BrianJewett (author)  crob13 months ago
Yes. If you have clean bare metal, that's what I would use. If you have any rust, I'd put on a coat of penetrol first to neutralize it. Then carefully and lightly do some fine wet sanding to level out any brush marks. when it's clean and dry again, I'd give it several coats with the spray poly. That's what I did with the bathroom countertops 4 years ago. So far, so good.
crob1 BrianJewett3 months ago
Thanks Brian. I will give it shot and see how it works out.
ShandaS3 months ago

Hey, just wanted to add my appreciation to you for taking the time to post this VERY helpful information! I recently started working with metal and, like others, have searched for a solution to keeping the rusty look without letting the thing just rust away. I've seen a lot of mention about Corten metal, but for my local shop it's a custom order and pricey. You saved me!

(removed by author or community request)
BrianJewett (author)  Keegan McClain6 months ago
Hmmm... It looks like a question I got in my e-mail has been removed but it you were still wondering, I'd wipe the panels down with mineral spirits or alcohol to remove any oils ant then either use the Penetrol & polyurethane top coat or since there's no rust on the new panels, you could seal them with a paste wax. This looks like naked steel but still seals the surface to prevent rust.

Thanks for the help Brian. Here a pic of the new Design area at Noble Plastics. The renovation is not done, but the walls in the design studio look and work great!


I'm working with Keegan on this project. How much area can we expect to cover with 1 gallon of the Penetrol?

Also, can you recommend a matte polyurethane top coat? Does it matter if it is oil-based or water-based?

trishbohr4 months ago

Hi, I bought 90' of antique iron fence panels. They have been stored outside for years and are pretty clean but have surface rust. I love the aged appearance and It sounds like Penetrol might be a good option for me. I don't want the structure to rust away. Do you think Penetrol would work to preserve them and would you apply a sealer to finish them and protect them from the Midwestern winter?


Trish Bohr


BrianJewett (author)  trishbohr4 months ago
I don't have any experience with long term weather exposure so I'm not sure. I think the Penetrol is linseed oil based with hardeners. You may be better off without the polyurethane over coat outside so you can just re-coat them periodically without sanding. If you have a really good paint store (not just a hardware store) in your area they might be able to answer this better than I can.

Thanks Brian. I sanded and used Penetrol on a 10' panel today and love the look. I rubbed the Penetrol on with a cloth glove and it covered easily so re-coating wouldn't be a big deal. I appreciate your help!

BrianJewett (author)  trishbohr4 months ago

You probably don't need to sand. Just knock off the loose rust with a steel wire brush, then clean the dust off with a hose and let it dry well. Wire brushing will get into the low spots better and won't change the surface texture.

A little hard to see, but in this picture the front panel has been treated and the others have not. I actually didn't sand, I used a wire brush on my drill to remove the rust then applied the Penetrol. I'll attach a better before/after pic when finished. Thanks again!

Hotpickle274 months ago

I'm attempting to make matching (w/cut out pattern) candle holders and light sconces out of rusted / reclaimed tin cans and duct metal. I am wondering if the Penetrol & Polyurethane treatment would be safe to use when adding the heat of a candle or lightbulb??

BrianJewett (author)  Hotpickle274 months ago
I would think so, but I've never done a burn test on either material. As long as you're not exposing the coated metal directly to the heat of the flame I don't think there's be an issue. Like almost any paint or coating, if you put it in the fire you're probably going to ruin the finish and create some nasty fumes. Test your application outside in a safe area if you have any doubts.
bmehl5 months ago
I'm fabricating a steel/wood bar and want to keep the raw steel look. The top is 10GA plate that meets up with reclaimed beams that make up the bullnose. The bulk of the bar will have to be built inside the restaurant so I may not be able to spray on polyurethane. The bar will see a ton of traffic. I considered the penetrol then a few coats of wipe on poly. What would you recommend? Penetrol / poly? Johnson paste wax?

BrianJewett (author)  bmehl5 months ago
I don't think the wax will hold up to the heavy wear. Even Polyurethane might not be up to the task unless you are willing to embrace scratches etc as patina. I think powder coating needs to be sandblasted but I'm not sure. It's pretty tough and available clear. You might also consider a heavy resin coating. You don't need the Penetrol if the steel is new and rust free.
C57Acuna5 months ago

I'm hoping your method of Penetrol/polyurethane will work on this rusty antique iron bed I found recently & want to use in a bedroom of my 1930 home. It had some flaky, bright gold paint, which I've gotten off. It's covered in rust, which I'm in the process of getting off. I'm kinda liking the metal color that's emerging and would like to preserve it, Hours of research have only resulted in ways to paint. Will the Penetrol turn it all black? I want to keep it it's own color as much as possible. I've all ready spent more on fixing it up than I did to buy it. I'm looking forward to hearing from you. Thanks.

Bed- rusty anique iron bed   2.14.jpgBed- getting the paint off   2.14.jpgBed-  getting the rust off   2.14.jpgBed with supplies   2.14.jpg
BrianJewett (author)  C57Acuna5 months ago
The penetrol will not turn the rust black. It only darkens it the same way as getting it wet does. This is a perfect application and exactly what I've used it for.
Great. I'm hoping to finish it this week cuz I've got guests coming Friday & right now the mattress is on the floor. Thanks.

We are installing raw steel sheet metal panels to use as magnetic pin boards in my office. We want to keep the raw metal look, but not the hand prints from installation. What would you recommend I do to remove undesirable hand prints before the applying Penetrol? Or is this something that will not show up?

Aucapucin7 months ago
Nyalic clear surface protectant is great for sealing in rusted or bare metal surfaces, patinas, etc, and it protects them too. It will also prevent tarnish of metals and stop fingerprinting on shiny surfaces. The results will last years but you can remove or repair the coating easily, too.
BrianJewett (author)  Aucapucin7 months ago
Do you have personal experience with this? From what little I was able to find, it looks like it's just for hard, clean smooth surfaces. I saw no mention of being able to use it to preserve rusted or corroded surfaces. It also sounds like pretty nasty stuff to use and not very hard or abrasion resistant.
ebehan8 months ago
Thanks!! Can't wait to use this on this piece to keep it looking like I found it!
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BrianJewett (author) 8 months ago
I should mention that after 3 years the area on one of these sinks where a soap bottle sits, has sprouted some fresh rust. I probably should have done 5 or six coats of poly instead of just 2 for a bathroom counter top. I should also find a better way to dispense soap in the bathroom.

I have a natural aversion to letting water stand anywhere. I have to wipe it up. It's just my nature. I treat these industrial steel counters like they were hand rubbed walnut. My wife, however, is not burdened with my affliction. She first wets her hands thoroughly, then without even a moments hesitation
, goes straight for the soap pump and leaves it sitting in about a tablespoon of water. Pair this with the fact that she's a fiend about washing her hands every time she goes near the kitchen, and you have the soap dispenser pretty much sitting in water for 3 years straight. So, even though the soap bottle is plastic, it's wet and being pushed down on a dozen times a day. In retrospect, it was obviously too much to expect from 2 coats of polyurethane.
Hi, I have an early 1900s cast iron and steel apothecary cabinet (glass door and sides). I stripped all paint with something like Stripeze and rinsed with mineral spirits/paint thinner, but it keeps rusting. I'd like a gray, gunmetal appearance. Do you think this product would work? If so, any ideas on how to get the rust off (powdery, like if you didn't immediately dry a cast iron frying pan) first?


Houston, TX
BrianJewett (author)  hathawayfarm8 months ago
Naval Jelly will take the new rust off. If you actually remove all the rust you won't need the Penetrol. Spray on a few coats of polyurethane to seal the surface and preserve the raw steel look. Don't brush it on. The brush marks will stick out like a sore thumb on the flat steel surface.
Ok, this is great info. And I get what you say about being sure to spray the poly. Do I rinse the naval jelly off with water? Will that make it rust again? Or should I just wipe off the naval jelly?

Can't wait to get this cabinet finished and back in the house!

BrianJewett (author)  hathawayfarm8 months ago
The water will only create rust if you leave it on the metal. I haven't actually used naval jelly since I was a kid (40-50 years?) I seem to remember it getting rinsed with water but follow the instructions. Just wiping it may leave a residue that could cause problems with the new finish. To thoroughly remove any water afterwards, I'd towel dry and then follow up with a hot air gun, blow drier, torch etc to warm the surface and be sure any water in cracks and seams is evaporated. Then coat it right away to seal the surface so it doesn't rust again.
pdub778 months ago
This is exactly what I was looking for! So glad the bot didn't bump you off for good. Thanks so much!
BrianJewett (author) 9 months ago
I don't know about other metals but for steel or iron, penetrol is a rust converter, It chemically changes the iron oxide to a different compound and stops the corrosion. If your patinas are corrosives that actually cause oxidation of your base metal it may work. If they are just color coatings I don't know if it will have much effect.

The penetrol itself isn't that hard. That's why I suggested a topcoat of polyurethane. Jewelry is a pretty tough, high wear application. You could experiment, but I'd also check with other jewelry makers or materials suppliers and see what they think about the specific materials you're working with.
oh my gosh, i really needed to read this. this has been an endless search but let me see if you think it may work for me. i make jewelry with a patina and all of my coatings have either come off or changed the color of the patinas causing the patinas to come off within months. you are saying i can put this directly on the finished piece and it will seal the color, then put another sealer on top of it? if so, what would prevent the final coating to not rub or wear off as before when used without the penetrol?
BrianJewett (author) 9 months ago
Which ever brand you like should work fine.
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