1275 OSPHO GAL Metal Treatment Coating, 1 Gallon, Green, 128 Fl Oz

First of all, this stuff actually does what it says. It cooks into crusty rusty crap and turns it into a very hard black coating that paint sticks to well. What it works well on is evenly rusted bare metal. Something that most of the paint is gone. Think like a truck frame or something that has been out in the elements a long time. What it isn't good for is treating surface rust on painted surfaces. On rust it dries hard and black. On anything else it leaves a sticky residue that will need to be cleaned off prior to painting. It's oddly satisfying to use this stuff because the chemical reaction is instant and noticable. You get a little sizzle and foam like hydrogen peroxide on a cut. It smells, you won't want to use it in your house at all. I've found the most effective way to apply it is with a paint brush. Spraying it doesn't work it into the rust as well and wiping it on with a rag gets all snagged in the scale. Ultra cheap bristle brushes are best. If used properly on what it is meant to be used on, this stuff is a miracle at a bargain price.

Great product for protecting metal before painting. I haven't had any problems using it the I follow the directions that are provided.

I have looked for a good rust preventer all my adult life. This product is it! It is widely used in Marine applications. Just pressure wash the rusted area, let it dry, pump spray on the OSPHO and let it dry 24 hours or until the rust turns black. Hand brush off any white powder that appears, then spray paint it with Rust o luem Truck bed liner. I used it on a 30 year old Kubota Tractor and Landspride tiller 3 years ago. No rust to date! I just did my 03 chevy silverado frame and it came out great! I am stoked!

Okay, I knew this before I bought it from reading various body work forums, but I found out for myself: This stuff works as advertised. Clean off loose rust..I hit it with a wire brush and left only the really small stuff. Ospho absolutely converts it to a black, paintable surface. However, their instructions say to let it dry fully overnight, and then you can paint right over it. WRONG. If you do that, unless you are very lucky, it will peel off. What you MUST do with Ospho or any other acid-based rust converter is, CLEAN IT OFF first. So let the Ospho sit overnight. Your rust will be black the next day. Then lightly wet it with Ospho again, let it soak, and wash it, HARD. Then clean it with solvent, and you'll have bare metal and dead rust to paint over. At that point, I'd hit it with some epoxy primer to seal it, and then go about the rest of your paint prep, knowing that the rust is dead and gone. Just don't paint right over it. That won't end well. Other acid-based products typically tell you to clean it off before painting. You can search Ospho on body shop forums and find plenty of folks that will back this up. But by all means, buy the product if you have rust. It definitely works. I bought the gallon and put it in a spray bottle. Works great.

I gave it 5 stars, cause the product works great. An good price value. But like other reviews, some does leak out in shipping. I lost about a cup 8 ounces. It comes double wrapped in a plastic bag. So it didn't get all over in the box. I wouldn't order anything else with this product, for fear if they are shipped together in the same box, an the product leaks, it could potentially get all over what else is in the box. I really like this product though. It is easy to apply to whatever your project may be.

I have a 1973 Mazda RX2 that had quite of bit of surface rust on the quarter panels. I initially decided to sand it down, but it really wouldn't budge. Wire wheeling helped a bit, but it can cause sheet metal warping if your too aggressive. I decided to buy some Ospho hearing about it on the forums.. It really does wonders! I was able to red scotchbrite about 40-60% of the lighter surface rust off, and all the raised smaller rust blisters, I was able to sand down easily after treatment. The rust that did not come off became a black primerable surface. Keep in mind there is specific acid neutralization that is recommended if you are painting with Epoxy Primer. There will be adhesion problems down the line if you do not follow the primer manufacturers recommendations. The coating that Ospho creates to protect the metal will not have good adhesion to epoxy primer. SPI specifically recommends to rewet the surface with Ospho and wipe it down using wiper. Please research prior to using the product if you are planning on using automotive primers. Also.. wear gloves and buy a decent spray bottle.

So I did the scraping and knocked off all the loose scales off the frame.. Did decide to use the media blasting to get the stubborn rust off the frame completely. The folks did the media blasting use ospho.. to prevent the flash rust. I also applied my own ospho after it dried off and I was able to clean and prep the surface again. Bottom line the product is awesome and I use it on everything that has rust now.

Works well on surface rust. Deep rust requires 2nd or 3rd coats. Remember to wash it off with water after setting for a while.