Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Questions in Prepping with Skyco Ospho rust converter
Q. My mother had a cattle corral built with oil field pipe which has a rusty look. It is not rust flakes. She has applied some of the Skyco Ospho [adv: Ospho on
eBay or
Amazon [affil links]
and it turned white. The instructions say you can wipe it off. This does not seem to be wiping off. Will this cause a problem or will it bleed through her paint if she paints over it?
Thanks for any response that would help her.
- Victoria, Texas
2000
A. Hi, Martha. The instructions don't seem to quite say you can wipe off the powder; they say that you should brush off any loose powder. I suspect that the fence was maybe Ospho'd and left unpainted longer than overnight, so that more powder developed than usual, but I'd just get it painted. Good luck!
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Q. I have used Ospho in my welding shop for a long time. We are looking for an anti-rust product to use on b-7 carbon steel bolts between flanges. We are not able to break these flanges and clean the bolts. We would like to possibly use the Ospho in a spray to coat these bolts. I also need a MSDS sheet.
FREDDIE J MARTIN- MONT BELIEU, Texas
2001
A. Hi, Freddie. I don't think that's really what Ospho is for -- it's meant as a pretreatment for paint.
You should get a current MSDS from the manufacturer; our kind readers included part of the MSDS and references to where to get it in a response to thread 7445.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Patio furniture and Ospho Refinishing
Q. I have wrought iron patio furniture that I coated with Ospho [adv: Ospho on
eBay or
Amazon [affil links]
. Before I had the chance to paint this furniture-it rained and turned all the furniture almost white-like a powder. I don't know what to do now. Do I re-coat it with Ospho? or do I paint over it? or do I remove the powder with a high pressure washer and then paint it?
Your help in this matter would be greatly appreciated.
Thank you.
- Victoria, Texas
2002
A. I don't think the while powder will hurt anything. Sometimes that happens anyway. I would just knock off the excessive powder with a Scotch Brite ⇦this on eBay or Amazon [affil links] and paint it with a zinc dust ⇦this on eBay or Amazon [affil links] , and then finish it with an enamel.
Joe Linux- Kailua, Hawaii
2002
Dealing with rust on clawfoot tubs, fences and garden ornaments
Q. Question about
Ospho [adv: Ospho on
eBay or
Amazon [affil links]
I have a clawfoot tub that has lots of rust on the outside. I was wondering if anyone could tell me if OSPHO will work on it. Do I just put it on over the rust or do I need to try to get more off? I have sanded and use a wire brush and have about as much off as I can get. I know that I should probably sand blast it first, but I really can't afford to do it right now and I really want to get this tub done so I can finish my bathroom.
If anyone can help me with my questions I thank you.
- Scammon, Kansas
2002
A. Hi, Sherry. That's pretty much what Ospho is for. Remove the easy rust, and "paint" over the tougher stuff. Good luck!
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
br
Coating Ospho with Polyurethane?
Can Ospho [adv: Ospho on eBay or Amazon [affil links] be top coated with polyurethane coatings?
Charles Slaughter- Prineville, Oregon
2003
A. Hi, Charles. According to Ospho, if I'm reading right, you can apply any paint system you wish. I don't see any reason to suspect that polyurethane would not be okay. Good luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Treating zinc coated steel with ospho
Q. I am in the process of restoring a 1980 El Camino and in the bed of the truck and tail gate there is a zinc type coating that has some corrosion (white). Can I use phosphoric acid treatment (Ospho [adv: Ospho on eBay or Amazon [affil links] ) on this type of metal to stop this corrosion before painting? I have stripped all the paint off and don't want to have to sandblast the whole bed surface if I don't have to, Thanks.
James Aldermanhobbyist - Elenton, Florida
2004
A. Hi, James. Ospho or equivalent ought to be fine for this. The Ospho instructions suggest that the best appearance on galvanized metal can be obtained by rinsing or wiping it off after a half hour, but that it should also function fine if dried in place for a day.
Even still, if you are going to paint galvanized metal, I'd use a Self-etching primer
⇦this on
eBay or
Amazon [affil links]
after the Ospho.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
March 19, 2009
Multiple threads merged: please forgive chronology errors :-)
Cleaning concrete and tile surfaces stained by Ospho
Q. I recently used the Skybryte Ospho product to prepare wrought iron railings for refinishing. Small amounts of overspray, which contains phosphoric acid, contacted concrete and non-ceramic tile surfaces adjacent the railings, causing white spots to appear and reappear, even after scrubbing with a wire brush. What product would work to remove these spots?
Henry Masonowner home renovation business - Virginia Beach, Virginia
September 15, 2008
A. Hi, Henry. I'd try letting a solution of sodium bicarbonate (baking soda [in bulk on
eBay
or
Amazon [affil links]
) and water sit on it for a couple of hours. Maybe made-up at one small box in a couple of gallons of water.
Baking soda is safe and should neutralize the residual mild acid that seems to be absorbed into the pores and is attacking the concrete and tile.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Q. Hi, I have used OSPHO for a long time to stop the rust and as a primer; a company I worked for used OSPHO so that's how I got into using it.
I have a chain-link fence that has turned to rust in areas, it was galvanized at one time, would OSPHO work to kill the rust so I can paint it? And what kind of paint would you use?
And where do I get some more of the OSPHO, every one has got into my stash and I am about out. The fence I need to do is 900 feet long, how much do I need?
- Troy Montana
May 4, 2009
Q. I have a 2008 Jeep Wrangler and it has an area of pitted rust and Chrysler states that it is normal. I now have to take care of it on my own. Is Ospho the best product to use and what is the best way to take care of it.
Thanks,
David
Insurance - Mulberry, Florida
October 11, 2009
A. Hi, David. I think Ospho is usually the best type of product for this situation; we hesitate to pick one brand of rust converter
⇦this on
eBay
or
Amazon [affil links]
over another though. The general idea is that you are trying to use a phosphoric acid based rust converter
⇦this on
eBay
or
Amazon [affil links]
to convert this porous and dusty red rust into the more stable black rust.
If the area is easily accessible and the operation is practical, I'd actually say that sandblasting is actually better, but usually that's not practical. Good luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
October 12, 2009
Q. I hired a handyman (who said he had used Ospho before) to paint my wrought iron railing which had started to rust. He did not let the Ospho dry overnight before painting it black and now there is a white powdery surface on the black paint. What can I do at this point? I would appreciate any advice.
Karen Bennett- Mill Valley, California
November 18, 2009
Searching for phosphoric acid product to be painted on rusty metal
Q. Many years ago I had a liquid product that when painted on rusty metal turned the surface of the rusty metal into a black "powdery" paintable surface. I know the active ingredient was phosphoric acid. I'm not looking for a primer spray paint or naval jelly. I am searching for a liquid product that can be painted onto a surface. I am searching for that product to be purchased in New Jersey. Please help!
Joanne Kaiserprotecting outside garden ornaments and fence - Somerset, New Jersey
May 28, 2013
A. Hi Joanne. We appended your inquiry to this thread because I'm quite sure what you are looking for is Skyco Ospho.
Good luck with it!
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
June 1, 2013
Q. Do I have to let this stuff dry completely before I apply finish paint?
Angel Pagan- Wrightsville Pennsylvania USA
July 16, 2014
A. Hi Angel. If by "this stuff" we are still talking about Skyco Ospho, their instructions say to allow to dry overnight, and they give a phone number to call for clarifications. Good luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
July 2014
Q. How do you get it off concrete?
TOMMIE SMITH- BURNET Texas usa
August 23, 2015
A. Hi. I'm not sure what you mean by "get it off". You should be able to just rinse it away. The Ospho directions say: "Avoid getting OSPHO on adjacent areas such as painted surfaces, concrete, masonry and stonework. If splashing occurs, flush immediately with water to remove.".
It is acid and will attack concrete if left there for any time. And you can't undo any attack that it has done; you would have to repair the concrete.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
August 2015
Q. I am restoring an old bakers rack. It is made of wrought iron, with brass trim. The brass trim pieces do not come off, and I need to treat the iron for rust. I have used OSPHO on other projects before, with good success, however, I can't find any information on how it affects non ferrous metals. Will it mar or etch the brass?
Patrick Cooke- Orlando, Florida, USA
February 12, 2017
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