OSPHO rust converter

[djhudson05]

Has anyone ever heard of or used OSPHO brand rust remover /converter?
Seen some in a supply store today and wonder if its worth the money for stopping rust and how is it for long term use?

 

[bax]

Heck yeah. It works good. wear a mask.

 

[englewoodcowboy]

It's the best stuff ever... well it works good anyway. hen you apply it, do not spray it as it is acid based. When it drys on anyrust it turns it to a black scaly stuff, a quick wipe with a scotch brite bad and you are squeaky clean. I use it on clean metal that wont be painted anytime soon and it keeps it from turning.

 

[TN1776]

Ospho, Jasco rust converter, and a host of other similar products that turn rust into a black, paintable surface have phosphoric acid as the active ingredient. The chemical reaction basically turns rust (iron oxide) into black iron phosphate which is more stable than iron oxide but by no means a weather-proofer. It does seem to make a decently stable primer type surface though - I've had good luck with it on a trailer frame I've been working on.

 

[kkhammer]

Its big in the marine and industrial world's, good stuff, not really intended for nice finish prep though... I believe Rust-mort is the same type of thing??... maybe not.

 

[broncodrew]

it works great...i just used it on my bronco. i used a paint brush and went over the spots that were rusty then let it sit then scotch brite the area before primer and then paint. If you read the instructions, you can paint over it...yeah, i don't think so. good luck.

 

[bigmuddy]

Please elaborate on not painting over the dried OSPHO. I am working rebuilding a car trailer and bought a gallon to use on the older parts that have surface rust. My intention is to wire wheel the rusty parts, then use the OSPHO and then top coat with a rust prohibitive paint. Does the OSPHO leave a powdery film? or what?

thanks Ben

 

[bmc69]

Ospho does leave residue that must be mechanically cleaned up before painting. We routinely use Ospho (I'm in the business of building boat) and usually its then followed by a good epoxy paint system.

Ospho is sometimes trucky to use on very rusted surfaces; you end up applying it more than once to complete the rust conversion process in some areas..which results in excess chemical residue in others. Great stuff though...been using it for 30+ years.

 

[zombie66]

I just used some last spring on a 40 year old boat trailer and like bmc stated some of the areas needed several coats and left a powder residue. I "mechanically" removed mine with a wire brush;D and a couple good coats of paint.

 

[OX1]

Ospho does leave residue that must be mechanically cleaned up before painting. We routinely use Ospho (I'm in the business of building boat) and usually its then followed by a good epoxy paint system.

Ospho is sometimes trucky to use on very rusted surfaces; you end up applying it more than once to complete the rust conversion process in some areas..which results in excess chemical residue in others. Great stuff though...been using it for 30+ years.

How does it compare to just painting POR-15? I've got close to 14 years on a rear bumper off my original 78 mud bronc. Yup, it's faded as heck and just now starting to bubble through in couple areas, but it had much tougher life than anything that lives on a rock crawler (and also sat outside for many years unlike my pampered rigs now).

Planning on doing my frame on the new build with "something" in the spring.

 

[bmc69]

How does it compare to just painting POR-15? I've got close to 14 years on a rear bumper off my original 78 mud bronc. Yup, it's faded as heck and just now starting to bubble through in couple areas, but it had much tougher life than anything that lives on a rock crawler (and also sat outside for many years unlike my pampered rigs now).

Planning on doing my frame on the new build with "something" in the spring.

Hard to say OX..roughly about the same? I use both with equally good results. However, the Ospho is a reactive treatment and not a thicker 'paint' like POR-15..so it lends itself better to being a substrate treatment when you want to apply some other paint system over it. POR-15 is gaining wider acceptance in the marine world though..especially since the higher VOC paint systems (often the better ones for service life) disappear from the market.

I'm still using exclusively POR-15s system on all the frames I do...

 

[dead road]

I believe with rust -mort the directions say to wipe it off within 24 hours or something like that. Within 24 hours its still kind of a soft jellyish material and wipes right off. If you let it dry hard it won't come off and leaves residue on the metal. I sanded and used a wirewheel to get it off the best I could. Even after that I had problems with my epoxy primer wanting to lift in those places. Moral of the story is don't let it dry on hard, or unlike me simply follow the directions.

 

[bigmuddy]

10-4 guys, I will make sure to get the powdery residue off before painting.

 

[djhudson05]

Sounds good. My son has a 90 FS Bronco I bought for him ( I tried to talk him into an early one, but you can't tell teenagers anything) and it has some rust issues. The frame is rusty and looking for something to keep it from rusting any more, at least for a few years.
Thanks for the input!

 

[englewoodcowboy]

It will stop and convert the rust but you will have to paint it to seal it up. It is not a 1 step product like POR15 is but me personally, on the frame and if your not looking for show finish, just POR and be done with it.

 

[fablife]

X5 ..on the rust convertor, it is great stuff! it is a very good paint prep. yes, you need to wipe off the powdery residue before painting tho.
FYI, it is not recommended under POR 15. it will probably work, but the application instructions for POR 15 read it is not recommended.
hth, JD

 

[bigmuddy]

I got my trailer project wire wheeled on saturday around 4 pm. I put on a good mask and face shield then put some OSHPO in a spray bottle and started spraying it. It didn't take long and and I had everything covered. I was pretty amazed as I came back around 10pm and most of the rust had already turned black and I assume converted. This morning I took another look and found some of the more heavily rusted areas and places that I hadn't prepped well enough will probably need some work. So far I am impressed with the converter. I am hoping to get the trailer painted over the christmas holiday.

 

[ep67bro]

OSHPO is good stuff. I used it for years working on boats in a museum. It is nice because you can brush it into hard to reach places. Also if you have rust streaks on a house or boat put some on a rag and wipe the rust streaks off. I always painted over it with a good zinc primer then finish paint. Used it on the frame of my 68 frod truck I restored and it worked well. I used to be able to get it in the hardware store but cant any more.

 

[Skiddy]

it does work very well. they won't let us use it no more here at work

 

[HGM]

OSHPO is good stuff. I used it for years working on boats in a museum. It is nice because you can brush it into hard to reach places. Also if you have rust streaks on a house or boat put some on a rag and wipe the rust streaks off. I always painted over it with a good zinc primer then finish paint. Used it on the frame of my 68 frod truck I restored and it worked well. I used to be able to get it in the hardware store but cant any more.

Would that work on painted surfaces of a truck? I did some grinding near my F-150 and now have rust specs on it..