I keep hearing about this Ospho stuff sounds like a cheap fix for rust problems. I am still new to body repair going to have to learn on this truck because it needs alot of it. I was wondering does Ospho hurt fuel lines or wires? I mean can I pessure wash the bottum of my truck then spray every thing uderneath ? Or do I have to remove certain things?

 

it don't eat the steel, it neutralizes the rust.you should give it a good pressure washing first to get all the rust flake off. then spray the ospho on. it will change color when it is done doing its thing. black if i remember correctly.

 

While I was careful in applying it to my crewcab's frame, I did manage to dribble it on various things I didn't remove (fuel lines - I just pulled them off the clips and let them hang, and so forth). It didn't eat the flexible portions of the fuel and brake lines, but it's not something you want to dribble on your fuel connectors for example - because if they are rusty - the rust is going to be converted to primer, and you'll never get them open.

If you have the bed off, you can just unclip the electrical, brake lines, and fuel lines and let them dangle a few inches away from the frame, then you apply the ospho inside the frame with an ordinary cheap paintbrush.

And yes, the rust turns black, for a nice "pickled effect" like so:

AFTER OSPHO:



AFTER PRIMER/PAINT:

 

I wanted to use it on the bottom of my bed, cab and under the hood and inside my fenders too

 

I used it on the frame, suspension bits (arms, rear axle, shock/spring perches, etc), the bed and cab bottom.

My fenders are new, and the hood is being replaced eventually, so I didn't bother with that.

 

Thanks for the info

 

Ospho is awesome stuff. Wear gloves when using it if you have any cuts on your hands though, it will sting pretty good. Ospho contains phosphoric acid, it will also stain your concrete white. I would try to find Right Stuff, here you get it at Advance Auto parts, its about half price.

 

I am also looking for a good rust converter, does ospho or Right Stuff do anything to unrusted metal. I wanted to use it on my bed inside and underneath. The rust converters I have used seemed to mess with the clean metal. Also, can you do anything to help smooth out the dried ospho before topcoating it, like sanding it?
Thanks guys.

 

It looks kind of like a clear coat when applied to clean metal. It is supposed to act like a primer so it can be applied to all the metal parts, rusted or not. It can be sanded if you must. I only had one problem with it and I am not positive it was the Ospho. I used some Pittsburgh Paints metal paint that didn't stick to good. The paint store blamed the high humidity, I am not so sure as I painted the item over many days. Either way, it works great on rust.

 

Some paints don't stick well to ospho for some reason, and why I paint over it with rustoleum industrial primer for a smoother finish, if I even bother.

For things like frames, floorboards and such, you can slather on two coats of ospho and not worry about it. In fact the instructions on the bottle suggest that.

I was worried about having "primer" exposed, but it appears to be so hard that it's not like normal primer that absorbs moisture.

 

Beats sand-blasting in a number of ways. Less chance of peening-over rust pits.

I used phosphoric acid to help remove my engine compartment paint, convert rust, and clean out the nooks and crannies. I followed-up with multiple treatments like this: wire-brush, Scotch-Brite scrub, and a baking-soda/soapy wash at the end.

You should clean off the area very well afterwards, like with a power-washer. It leaves a waxy/soapy layer on top that will protect the metal for a while, but will interfere with permanent paint. Primer goes over it, and sticks to the 'toothy' surface nicely.

Cold application has a priming effect, and will get down into rust pits better. It will take off all but good paint, and get into scratches. Warmer application, and time, will plug rust pits, convert the rust it can reach, and damage good paint. It isn't the best paint remover, but sure helps. So, I would do cold treatment first, and finish up on a hot day.

I have soaked heavily-rusted dashboard vents for days at 65-90 degrees, and they came out great. I could see the waxy layer on top, and it takes a little agitation with detergent to get it off.

This is the acid used in self-etching primer. But you still need to prime the black coating that is created. That is Iron-Phosphate (I think). Same stuff as on replacement sheet metal. It hides new rust until it is bad, so prime and paint.

If you can't get into crevices and voids, I would try power-washing, then at least spray with WD-40 (fish-oil) or silicone. Better yet, use an oily underseal product.

Do not get this in your eyes. Bad stuff. Thick high-gauntlet Nitrile Gloves are recommended. And keep it out of your ground-water supply.