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

This works great to kill rust and prevents it from coming back again great product been using it since a car restorer told me about this

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.

Seems to have a good kick not sure if it's the way I remembered it from the '90s but I would continue using the product as it works better than say Rust-Oleum.

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.

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.

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

This is the second gallon of this I have ever bought. The first gallon has lasted 10-20 years. Any time I am painting steel I use this first. It uses phosphoric acid to put a layer of iron phosphate on the surface of the steel. Paint sticks well to that. Is there more to it than the phosphoric acid? I don't know. It isn't perfect but the job is better with it than without. It will leave unwanted marks on paint, concrete, and other items that it may be left on for a long time. Water rinses it off.