View Full Version : Any one here tried or heard of Ospho???

cookin out
10-10-2012, 10:01 AM
I had a couple of guys at the marina tell me its available at NAPA and it is some sort of paint that is awesome for galvanized boat trailers.
They said it covers and kills rust, protects all parts covered with it and it lasts for years....one guy said he did his galvanized trailer 5 years ago and it looks like brand new with no rust anywhere on it.

One of them rebuilds old cars and trucks and says he always uses it on the frames and undercarriage of all his rebuilds....

thanks, rick

10-10-2012, 10:23 AM
The original ospho was awesome on rust. You simply brushed it on rust and corrosion and let it set until it turned white, wire brush it off. Then you applied a rustoleum primer and paint. I am also told that the EPA got ahold of it and reformulated it and now it doesn't work well, just like any other thing the Government touches.

The Cat's Eye
10-10-2012, 01:07 PM
Ospho is not a paint but actually Phosphoric Acid. I had no idea the product has been altered, but that doesn't surprise me. If you get one tiny drop of Phosphoric Acid in your eye you will realize why the gov't altered it. You pain threshold will be surpassed by miles and you will scream your lungs out until you get your hands on a hose and direct the stream of water into your eye for about 20 minutes. The reason I know this is that I was actually wearing eye protectors while working with this stuff, but a tiny drop passed through one of the tiny air vents and landed in one eye. It was so painful I could barely function. I still have some of the original stuff and when I work with it now, I apply tape over the air vents on my eye protectors.

10-10-2012, 01:14 PM
Osphro changes the chemical properties of rust. Once the metal is treated you must seal the area with paint.

P.S. You must clean off as much of the rust as you can before treatment with Osphro.

SCFD rtrd.
10-10-2012, 04:44 PM
It's only good for surface rust. You gotta wire brush or wire wheel the thick rust. I just used some on my trim motor. Had a little surface rust that was running down on my transom. Used a Drimmel tool to remove the rust, brushed on Ospho, let it sit overnight, wiped area off, sprayed with primer, then sprayed with black paint. Looks like new.

cookin out
10-10-2012, 05:01 PM
these guys were telling me its an all in one step type of paint......they said it goes on purple and dries either gray or black depending on which one you want?????? At least thats what I thought I heard???? maybe its just a primer???

10-10-2012, 05:07 PM
TheCatsEye is correct. But it IS an amazing product. As stated above clean the loose rust off, apply Ospho, let it sit maybe overnight and paint with a good rust resistant paint. Metal will stiil rust eventually but this will slow it down a lot. When I did Auto body work, I have grouns large areas to bare metal, applied Ospho, let vehicle sit outside under a car port for the weekend, monday A.M., no rust, at all.

FS Dan
10-10-2012, 11:35 PM
I was alway told that ospho was a surface prep so that you arent trapping already formed rust under your paint job. The one step prep is a product called Killz available at home depot. Its a rust converter/primer.


10-11-2012, 08:29 AM
Killz does not work on rust? Its a stain blocking primer.

10-11-2012, 12:05 PM
Ace Hardware has it too. Our NAPA has turned into no better than Discount Auto. :(

10-11-2012, 09:34 PM
these guys were telling me its an all in one step type of paint......they said it goes on purple and dries either gray or black depending on which one you want?????? At least thats what I thought I heard???? maybe its just a primer???

If it meets the characteristics you've described, it's a rust converter product, not Ospho. Ospho turns whiteish, think of galvanized that's starting to weather. If it's the same bunch at the marina telling you this, they don't know what they're talking about.
What are you trying to accomplish?? If the metal is starting to rust all you can do is slow it down. If the galv is fresh, grease it.
As for Kilz, it's a stain blocker.

10-11-2012, 09:48 PM
I worked on a couple of steel-hulled research vessels in the '90s and they bought Ospho by the gallon to use in spray bottles to remove the rust streaks on painted surfaces. Worked great for that.

10-11-2012, 10:05 PM
[orthophosphoric] you will need to prime and paint over it.but turns the rust hard.stops the bleeding.try the spray can rubber over it 10 bucks at home depot.sherwin williams has ospho

10-13-2012, 06:21 PM
krylon also has a primer paint that turns rust into primer

10-14-2012, 02:41 AM
http://www.por15.com/ Works better... Ospho has been around since WWII for rust... Read the POR-15 web site.. Dead stops that rust on older outboard steering arms..

Alex from GA
10-14-2012, 09:41 AM
Dunk has the right product. I used it on a painted trailer many years ago that was used exclusively in water.

10-14-2012, 09:52 AM
Ospho works well, I'll have to try the POR15 product.

The Cat's Eye
10-14-2012, 12:08 PM
POR 15 is a great coating. I use it on my homemade grapple anchors. The stuff dries very hard and seems to even be flexible, since it hasn't flaked off or even cracked on the steel rebar prongs of my grapple anchor. And this anchor has been in use for three full years.