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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Nooblet16 days ago

I used steel
wool to clean rusted steel and the Penetrol... I wiped it on with a cotton
cloth. I love the look how it is. I'm going to use it as a desktop – so it will
need to be more durable. This is my third try on getting the finish I want.
When I used polyurethane it came out too dark and shiny. Tried matte
polyurethane and it was streaky and cloudy. Has anyone tried a wax?

BrianJewett (author)  Nooblet16 days ago

You can use the wax on bare metal if it's clean & smooth but if it's pitted, you won't be able to buff the wax smooth in the low spots and you'll have the white residue showing. I don't think wax would be good over the penetrol. If you like the look with the penetrol, adding polyurethane top coats won't darken the surface any further. I'd use the spray on a nice flat surface like this. The brush on always leaves some visible brush marks.Try a flat or a satin on the back to see how you like the finish then put down at least 3 coats, more if you have the time and patience. Desks get a fair amount of abuse.

JMZ0072 months ago

it looks like Penetrol is exactly what I need to lock in some rusted metal I want to use in a project. The only problem is, I can't buy it in California. I can't get anyone to ship it to me either. I can get the non-oil-based replacement, Flotrol. However, I don't know if this will work the same. Does it? Is there anything else I can use in California that will produce similar results?

BrianJewett (author)  JMZ0071 month ago
Thanks, I have learned the hard way to always read between the lines and to pay attention also to what is NOT said. It's easy to read what I want to hear if I'm not careful.

The Flotrol is made by the same company 'Flood' and is the same product in that as Penetrol is for oil-based, Flotrol is for latex-based paint. BUT if you're just using it as a clear top coat (not over any paint) I bet it would work the same. Here is a link to the product description, but of course what BrianJewett(author)'s Instructable is about is how to use it 'off-label'. I'm going to try the Flotrol too, because it is a lot cheaper than its cousin ;-) I hope this helped a little.

BrianJewett (author)  bettina-sisr1 month ago
Do you know if Flotrol is a rust inhibitor like Penetrol? The primary function of Penetrol is really to be a leveling agent in paint, making it "flow" better to remove brush marks. If you want to use it like I do in this ible, it needs to be more than a leveling agent, it needs to penetrate and stop the rust.
I am far from being an expert :-) but from what more I have read from my prior post, it is to be considered the 'same' as Penetrol when it come to extended the life of paint only. It does not seem to be a rust inhibitor, so other than using as an additive to latex paint (& water based paints) I don't think it would work the same as Penetrol. The site says it makes latex and other water based paints behave like oil paints. I guess this is an experiment in the making...thanks for keepin' me on my toes!

bettina-sisr: Thanks for the response. Please let me know how Flotrol works if you try it. I'll do the same.

BrianJewett (author)  JMZ0071 month ago

I don't know anything about Flotrol. You should check with the manufacturer or at least with a good paint guy where you buy it if one exists.

ebehan1 year ago
Thanks!! Can't wait to use this on this piece to keep it looking like I found it!
13, 11:02 AM.jpg

Holy-Moly I LOVE that! As a metal worker I gotta say hats-off to whoever made this, and to you, ebehab for giving it some well deserved attention!

PiperL1 month ago

Not to be a complete idiot but can you give me a brand name for the polyurethane top coat? I'd be using them on rusty old concrete nails and railroad spikes. Thanks! And I LOVE your towel rack!! ♥

BrianJewett (author)  PiperL1 month ago
Any oil based polyurethane should be compatible with the Penetrol.
Jc Crow1 month ago
so in theory would this work as well to preserve light surface rust/patina on a car?
BrianJewett (author)  Jc Crow1 month ago
Sure, if you're going to keep it inside. ;-) As I've said in other replies, I have no experience with this combination outside but I have had just polyurethane only last a year or two outdoors. Cars are an especially tough application. I'd check with an auto body & paint person for advice on a car. Rust you can see on the outside usually means the underside is already gone.
stewart lee2 months ago

hi. i'm wondering if i can apply acrylic spray paint on top of a coat of penetrol? it will be a stenciled image on steel. thanks!

BrianJewett (author)  stewart lee1 month ago

I'm not sure but I think the rule of thumb is that you can apply water based over oil based paints but not the other way around. Anyone in the paint department should be able to tell you.

lizzyrex2 months ago

I apologize for reposting. The image didn't attach and it doesn't look like the comment showed up. I am wanting to seal these metal olive baskets so that when you touch them, you don't get rust on your fingers. I do not want the color of the basket or the rust to change. Will your method described above work for these? Thanks!

BrianJewett (author)  lizzyrex1 month ago


lizzyrex2 months ago
pitbullmama3 months ago

I looking on ideas for making a steel counter top I seen it on T.V. once but don't know how to treat it or the thickness of the steel I should use. Any ideas.

BrianJewett (author)  pitbullmama3 months ago
I used 10 guage (.135 or 1/8 inch) hot rolled mild steel for these counters. They are plenty strong for ANY home use. I'm sure you could use 12 ga as well (.105"?) I wouldn't recommend this finish for a kitchen counter though. The steel is tough enough but the finish probably wouldn't last. You could wax it if it wasn't rusted but you'd have to re wax it periodically to keep it from rusting. That's why stainless steel is popular for kitchens. It needs no finish.
LucyBW3 months ago

Wow - I love that streaky rust finish!

I am also trying to preserve/seal a rust finish but for a fire pit. So I need something that won’t result in toxic fumes if it is heated by fire. I read the fineprint for Penetrol and concluded it is not the right product for this application.

I am not expecting to find a sealant which will hold up over time and weathering
and fire. Its ok if the sealant breaks down when it is in direct contact with
fire but I’m not ok with toxic fumes.

Can you recommend anything???


BrianJewett (author)  LucyBW3 months ago
Actually, for a fire pit, I recommend nothing. If you want to keep the look of the rust, I don't think there's any clear finish I know of that will stand up to fire. My suggestion is to just let it rust. If it's fairly heavy metal, it will still last for years outside. The rust itself will build up a scale that slows down further corrosion.

Ah, that makes a lot of sense.

I was hoping to find something inexpensive that could result in a satin finish and clean to touch compared to straight rust. But everything I'm finding is either toxic and/or flammable, or requires hi-temperature curing (like hi-temp engine paint and clear coat), and I can't imagine hi-temperature curing preserving the rust look.

On the other hand the rust scale is not so dirty as the initial powdery rust. So I'm liking your suggestion to just let it rust...

Thanks for your feedback

Matt Weed made it!4 months ago

Used this on a frame for a ski lift chair. Works Great! After two years of high altitude sun and harsh winters it looks the same as the day it came out of my shop. Used one coat of Penetrol as the base, then did three coats of oil based polyurethane from home depot. All brush applied rather sloppily. Metal is clean mild steel.


Thats a really cool chair Matt. Do you remember what brand/specific product of brush on polyurethane you used?

I can't seem to find the can. I know there is some left in the garage somewhere... But, I'm 90% sure it was Minwax clear oil based polyurethane and that it said it was UV resistant/proof.
BrianJewett (author)  Matt Weed4 months ago
Thanks for the feedback. I'm not sure if the penetrol is needed on clean metal without any rust but it's good to know it's holding up outside.
kesellers19 months ago


I have found your post while trying to figure out how to treat table legs I will be creating. I am going to use black steel pipe from the hardware store to create table legs with butcher block top (see example picture). The legs will not be exposed to liquid, and they will be indoors, but the man at the hardware store gave me the impression they could still rust. He suggested I use some type of wax, but he wasn't specific. I do have small children so I need the legs to be safe for them and it will be pushed against my light colored sofa so it can't be anything that would rub off and stain. Should I just clean them well with steel wool and then use poly or should I use the Penetrol product you suggested? Thank you so much!

BrianJewett (author)  kesellers19 months ago
I've built several things with black pipe. I've always just wiped them down with mineral spirits (paint thinner) to be sure they're clean and then sprayed them with a few coats of flat polyurethane. I've been using a towel bar for over 4 years daily and it still looks like the day I hung it.

I used Johnsons Paste Wax for a steel bookshelf I built. It's good after 3 years but it will probably need re-waxing periodically. It's not as durable as the poly and it would not work well on the threads and fittings.

Hi Brian, I am also using black steel pipes as table legs. I have searched all over Calgary, Alberta for aerosol polyurethane that says it is good for metal, and cannot find any. One vendor said there might be environmental restrictions here that prevent suppliers from importing it. Are there any other products that would work to clear coat the steel? Could I use penetrol on its own? Are there brush-on polyurethanes that would work? I can find minwax polyurethane, but it says it is meant for wood. Was really excited to find this, but am discouraged now that I cant find any aerosol polyurethane.

BrianJewett (author)  adam.laws4 months ago

Wood is the most common usage but it's also good for a clear top coat on metals or other finishes. Any aerosol poly should work fine. Penetrol is not very hard or durable on it's own. If the pipe is clean with no rust, you can skip the penetrol and go straight to the polyurethane.

Thanks for the help! Its great getting advice from somebody who knows what they are talking about.

Thanks so much!!

My picture didn't work, but I think you get the idea. :)

csweet20144 months ago
Have you noticed any yellowing of the finish after a while? Ive read that penetrol can yellow over time since it contains linseed oil.

If its not, Im curious if topcoating it with a clear coat like you say will prevent the yellowing.

From my understanding linseed oil yellows due to its reaction with oxygen over time.

I've had a swing frame outside for about two years now. It looks the same as the day I finished it. The material is non-rusted mild steel so any yellowing should have shown. One coat Penetrol as the base and three coats poly on top.

BrianJewett (author)  csweet20144 months ago
I haven't noticed any yellowing but I probably wouldn't since I only use it on rusty steel. On the dark, red-brown color, a little yellowing wouldn't show.

Hi Brian, this is just the info I was looking for. I have an antique iron bed that is rusted and I would love to keep the look without the rust and paint getting all over everything. I will try this. Thanks!

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