I am in the process of building a 5-foot high pipe fence. The pipe is 2 3/8 and has some surface rust on it. Once I get everything welded I will need to paint before adding the no climb fence.

My question is, what is the best way to get rid of the surface rust before painting? Would muriatic acid do the job? A friend of mine said to go to a good paint store and get "phospho" or something like that which will kill the rust and will work like a primer. I have no idea on this, so any help would be greatly appreciated. Thanks.

I used a rust inhibiting primer and then painted our pipe fence. I thought about taking a wire brush to it first to knock off the rust flakes but deferred to the easier method.

MIAGD said:

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I used a rust inhibiting primer and then painted our pipe fence. I thought about taking a wire brush to it first to knock off the rust flakes but deferred to the easier method.

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Where did you get the primer? Lowes/Home Depot or a local hardware store?

I used a product called Ospho with pretty good success. I did buff all the welds first, knocked all the rust flakes off, applied the Ospho, let it dry, then put two coats of paint on it.

MarkPro said:

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I used a product called Ospho with pretty good success. I did buff all the welds first, knocked all the rust flakes off, applied the Ospho, let it dry, then put two coats of paint on it.

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That Ospho may have been what he was referring to. Where did you get it?

clarythedrill said:

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MarkPro said:

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I used a product called Ospho with pretty good success. I did buff all the welds first, knocked all the rust flakes off, applied the Ospho, let it dry, then put two coats of paint on it.

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That Ospho may have been what he was referring to. Where did you get it?

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Most hardware stores carry it. It's mostly phosphoric acid

Success might be based on what the pipe was exposed to, if it came from actual oilfield use. Sanding, wire brush, Ospho didn't work on ours, it started flaking after 2-3 years.
It required sandblasting, then went all out with an epoxy primer and paint (still great after 12 years).

Some of the pipe that is reject or unused, that rust may respond well to the sanding and Ospho prep route.

Neighbor with similar pipe to ours also had early failure (paint adhesion) with the sanding and Ospho prep route, anecdotal, I know, but just an observation.

Yup get Ospho at any hardware store, a paint mitt and wipe it down, then paint it how you want it.

Went thru this w new fence in Spring. My process-
- Wire brush by hand all metal
- wipe it all down
- repeat at tough spots
- ospho
- wipe down residue
- heavy duty paint w inhibitor built in. ( got mine from ACE)

It's work!!

GSS said:

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Success might be based on what the pipe was exposed to, if it came from actual oilfield use. Sanding, wire brush, Ospho didn't work on ours, it started flaking after 2-3 years.
It required sandblasting, then went all out with an epoxy primer and paint (still great after 12 years).

Some of the pipe that is reject or unused, that rust may respond well to the sanding and Ospho prep route.

Neighbor with similar pipe to ours also had early failure (paint adhesion) with the sanding and Ospho prep route, anecdotal, I know, but just an observation.

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This pipe is thinner walled than oilfield pipe and has not been used prior to me getting it. Ospho it is. I am thinking since it is water thin I will put in a pump type sprayer and spray it on.

Thanks to all for the advice on this, it is appreciated.

I will share my experience on our ranches with taking care of pipe fences.

The OSPHO product is phosphoric acid that chemically changes the rust by oxidizing it. It is a very thin liquid that you can either spray or brush on. You can get it at most farm and ranch supply houses and sometimes the box stores sell it. It can also be found in other brand names but it is the same stuff. It will burn your skin somewhat if you get it on you so be careful to not get in your eyes etc.
The directions will tell you to remove flaking rust first then apply it and then rinse with water.

On our ranch in Texas we have a lot of pipe fencing that I built about 30 years ago. Most of it was either 2 3/8 or 2 7/8 oilfield pipe with light rust. I used a right angle grinder and wire wheel and a hand wire brush to clean the pipe before painting. It was a long, hard, hot, dirty job that took a lot of effort and time for the amount of fence we have. I initially treated some of it with OSPHO then applied a good coat of Rust Oleum "Red Oxide Rusty Metal Primer". This primer contains fish oils that somewhat prevent further rusting. I then painted the fence with a paint called "Corral Coat" that is a very high quality industrial coating. It lasted for about 7-8 years before the paint faded and started peeling/flaking in the Texas heat and dry in our area.

My uncle used to work in the oilfield and he suggested I paint the fence, after cleaning and brushing, with a good quality aluminum paint. The aluminum paint will actually act as a primer and paint and holds up better than the coating above and does not flake or peel after a few years......however it will eventually wear off and you will need to recoat in again 7-8 years.

Now on our ranch in the Ozarks in Missouri we built about two miles of the same pipe fence. That was about five years ago. I decided to not prime or paint it at all and just leave the natural coating of rust. Rust acts as a natural oxidation and covering over the metal as I was told by a large pipe fence builder in Missouri. That area sees lots of moisture and rainfall/humidity as compared to our ranch in the northwest hill country in Texas.
We have since built horse corrals, turn out areas, round pens etc. with the same pipe and I have not painted any of it. It rusted to a uniform red/brown color and we like the rustic look of it.

If you live in a salt air environment I guess you really need to prime/paint to keep your metal from eventually rusting away.....however...

Bottom line for me was....once you paint a pipe fence you will be saddled with repainting every few years if you want it to stay looking nice.....no matter what you coat it with. Whatever you use to prime/paint, pay the extra money and get industrial coatings instead of using box store paints and primers. Rust Oleum makes some good industrial primers imho.
I have decided to never paint a pipe fence again and just let the natural rust layer protect the metal. I like the look of it and it aint going to rust away in either environments of our ranches. I just got tired in Texas of having to reprime/repaint miles of fencing every 5-7 years. On the Texas fencing I found the pure Aluminum paint to hold up the best long term.

If you do decide to prime/paint:

Dont apply either coating when it is so hot you cant keep your hand comfortably on the pipe.....the paint/primer will not adhere correctly if the surface is too hot.
After brushing and cleaning or OSPHO treating.....wipe the pipe with paint thinner/mineral spirits to clean it before applying your paint for better adhesion.

Thats just my thirty cents of what I have learned over the years on our ranches. Im sure there a lot of smart fellas on here that will give you some damn good input that are a lot smarter than I.

Gunny456 said:

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I will share my experience on our ranches with taking care of pipe fences.

The OSPHO product is phosphoric acid that chemically changes the rust by oxidizing it. It is a very thin liquid that you can either spray or brush on. You can get it at most farm and ranch supply houses and sometimes the box stores sell it. It can also be found in other brand names but it is the same stuff. It will burn your skin somewhat if you get it on you so be careful to not get in your eyes etc.
The directions will tell you to remove flaking rust first then apply it and then rinse with water.

On our ranch in Texas we have a lot of pipe fencing that I built about 30 years ago. Most of it was either 2 3/8 or 2 7/8 oilfield pipe with light rust. I used a right angle grinder and wire wheel and a hand wire brush to clean the pipe before painting. It was a long, hard, hot, dirty job that took a lot of effort and time for the amount of fence we have. I initially treated some of it with OSPHO then applied a good coat of Rust Oleum "Red Oxide Rusty Metal Primer". This primer contains fish oils that somewhat prevent further rusting. I then painted the fence with a paint called "Corral Coat" that is a very high quality industrial coating. It lasted for about 7-8 years before the paint faded and started peeling/flaking in the Texas heat and dry in our area.

My uncle used to work in the oilfield and he suggested I paint the fence, after cleaning and brushing, with a good quality aluminum paint. The aluminum paint will actually act as a primer and paint and holds up better than the coating above and does not flake or peel after a few years......however it will eventually wear off and you will need to recoat in again 7-8 years.

Now on our ranch in the Ozarks in Missouri we built about two miles of the same pipe fence. That was about five years ago. I decided to not prime or paint it at all and just leave the natural coating of rust. Rust acts as a natural oxidation and covering over the metal as I was told by a large pipe fence builder in Missouri. That area sees lots of moisture and rainfall/humidity as compared to our ranch in the northwest hill country in Texas.
We have since built horse corrals, turn out areas, round pens etc. with the same pipe and I have not painted any of it. It rusted to a uniform red/brown color and we like the rustic look of it.

If you live in a salt air environment I guess you really need to prime/paint to keep your metal from eventually rusting away.....however...

Bottom line for me was....once you paint a pipe fence you will be saddled with repainting every few years if you want it to stay looking nice.....no matter what you coat it with. Whatever you use to prime/paint, pay the extra money and get industrial coatings instead of using box store paints and primers. Rust Oleum makes some good industrial primers imho.
I have decided to never paint a pipe fence again and just let the natural rust layer protect the metal. I like the look of it and it aint going to rust away in either environments of our ranches. I just got tired in Texas of having to reprime/repaint miles of fencing every 5-7 years. On the Texas fencing I found the pure Aluminum paint to hold up the best long term.

If you do decide to prime/paint:

Dont apply either coating when it is so hot you cant keep your hand comfortably on the pipe.....the paint/primer will not adhere correctly if the surface is too hot.
After brushing and cleaning or OSPHO treating.....wipe the pipe with paint thinner/mineral spirits to clean it before applying your paint for better adhesion.

Thats just my thirty cents of what I have learned over the years on our ranches. Im sure there a lot of smart fellas on here that will give you some damn good input that are a lot smarter than I.

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Thank you for that information. I live about 20 miles west of Ft Worth, so average rainfall for the north Texas area. As for paint, I would love to just let it do its thing and rust, but all the houses around me have painted theirs black so I sort of want to look the same.

clarythedrill said:

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GSS said:

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Success might be based on what the pipe was exposed to, if it came from actual oilfield use. Sanding, wire brush, Ospho didn't work on ours, it started flaking after 2-3 years.
It required sandblasting, then went all out with an epoxy primer and paint (still great after 12 years).

Some of the pipe that is reject or unused, that rust may respond well to the sanding and Ospho prep route.

Neighbor with similar pipe to ours also had early failure (paint adhesion) with the sanding and Ospho prep route, anecdotal, I know, but just an observation.

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This pipe is thinner walled than oilfield pipe and has not been used prior to me getting it. Ospho it is. I am thinking since it is water thin I will put in a pump type sprayer and spray it on.

Thanks to all for the advice on this, it is appreciated.

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I've sprayed it on a trailer w a pump up sprayer with good results

AggieStan said:

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Went thru this w new fence in Spring. My process-
- Wire brush by hand all metal
- wipe it all down
- repeat at tough spots
- ospho
- wipe down residue
- heavy duty paint w inhibitor built in. ( got mine from ACE)

It's work!!

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Yes, do it now don't wait for summer! I painted both my houses this time last year. Too dam hot during summer.

Shoefly! said:

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AggieStan said:

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Went thru this w new fence in Spring. My process-
- Wire brush by hand all metal
- wipe it all down
- repeat at tough spots
- ospho
- wipe down residue
- heavy duty paint w inhibitor built in. ( got mine from ACE)

It's work!!

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Yes, do it now don't wait for summer! I painted both my houses this time last year. Too dam hot during summer.

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Haha, I have actually waited several months to start this project just so it would be cooler out. I hope to be completely done by the end of December.

https://www.amazon.com/gp/product/B000HBNX38/ref=ask_ql_qh_dp_hza?th=1

I've used OSPHO and Permatex before. Had best results from Permatex. Looks milky when applied to metal, then dries to a black finish. Paint the next day. No problems w/rust bleeding thru. Bought it at an auto supply.

I understand that for sure. If you go with using an angle grinder with a wire brush to clean use a cup brush rather than a wheel.
Also I found that Bosch makes a variable speed 4" angle grinder. So much better as you can turn down the speed from the 10,000 rpm and make it a lot easier to hold it for long times and it does not try to jerk the brush so hard.
I liked them so much I bought three of them!
Good luck and just think how nice it's going to look when you are done.

ETA... don't forget to wear good eye protection when using the wire wheel. Those wire pieces can fly out pretty hard. I had a few stuck in my fat belly at the end of the day!

I have a pipe fence around yard.
Knock off loose scale first then apply Ospho.
Knock off scale with sandblaster, needle scaler or wire brush.

Sandblaster is best if you have any new pipe with mill
scale.
Rent an air compressor and sand pot and it goes quicker than a wire wheel.
Do not skimp on a cartridge respirator, buy your own.

Wipe clean, apply Ospho let dry. . Prime and paint. Go to a paint store and tell them you're painting rusty pipe. They'll sell you the right metal primer for the paint.

Good advice. I had about 1.5 miles of pipe fence that had 4 rails. I rented the compressor and hood.
It used so much sand (16 foot flat bed full of sacs that I had to keep moving) doing the pipe and moving the damn heavy ass hoses and the compressor every hundred feet it was a real PIA. Plus it was hilly and the damn hopper cart kept trying to turn over.
I found that in the end I got more done with me and two helpers with the grinders.
No doubt a short level fence with a couple of rails would have worked well with the sand blaster

We have 90 feet of 3 rail 3" pipe fence on both sides of our entrance gate. A couple years ago the paint was peeling off and there was a lot of rust. Bought pro grade primer and red topcoat from Sherwin Williams. I bought a 7" hook/loop sander at Harbor Freight and it worked pretty good. Sprayed with OSPHO. Wiped with mineral spirits. Painted with a glove/roller. It took a week but looks great. Struck out on hiring someone to do it.

I'll just add my $.02 here. All of what has been said is good.

DON"T use the rusty metal paint with primer in one - it fades and cracks off after 2-3 years in the Texas sun.

DON'T use an Alkyd paint. It will fade and leave a chalky surface that will NEVER allow another paint to adhere. Must completely remove it and start from bare metal.

Sandblasting prep is always best. I've had mixed results with the OSPHO, if you do use it, be sure to wipe it clean with thinner/mineral spirits or else paint will not adhere well.

I (try to) manage a slaughter plant where steel is in direct contact with water constantly. One of the best things I have found is to use on metal that has already rusted: Wire brush, OSPHO if we have time, Cold Galvanizing for a primer and then two coats (minimum) of the rust-o-leum enamel paint. This seems to last for 3-4 years in a very harsh environment.

My best luck has been with an acid etching (epoxy) primer and Imron paint. Both of these are (in true OB form) more expensive, but you will not be putting another coat on near as soon and the prep to re-coat will be significantly less. I believe the trade off in higher materials cost has been offset the reduced labor cost of not having to redo it every 2 years.

If you really want the paint job to last you sandblast it first but it ain't cheap. Blast what you can paint in a dry day over 55F in 3-4 hrs , paint right away . Repeat same until you have the whole thing primed. .