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The Ospho Solution..(rust removal)

353K views 664 replies 61 participants last post by  Lizer 
#1 ·
This is the start of a thread dedicated to successful rust removal using ospho,a water based phosphric acid product I've been using professionally for many years.
Ospho has some advantages over other methods, mainly a DIY can do it at home inexpensively with little mess,fairly easily.
I'll try to answer any questions and offer some advice on the successful use of this product.
.....First,I'll start with the most common use : To remove surface rust That has accumulated on unprotected steel....Then heavly rusted and pitted metal,and using it to prevent surface rust of freshly stripped steel...
...
The pics below show the trunk floor and wheel wells I made for my old car.After making the pieces and screwing them together ,it got cold out and I put the car up for a couple months and the steel got pretty rusty.
In the interest of time I'll just do a spot to show how its done and what Materials you'll need.Bare with me I'm a newbie with the computer.
 

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#3 · (Edited)
I prefer a using a pump spray bottle (like an old windex bottle) but this will do for now.Apply ospho liberally and scrub it in with the scuff pad, keeping it wet, then wipe off the excess with the towels.let it sit 24 hrs.http://www.streetfire.net/video/rust-removalospho_743479.htm
This is pretty heavy, so If you want to clean it some more, just sand it down with 80 and You can reapply it a second time or as many times as you want. http://www.streetfire.net/video/rust-removalospho-2_743486.htm
I'm doing this outside like most of you will be doing.heres a picture of what it looks like after its dried compared to what it started off as.
I'll be posting much more later tonight, on other uses and prepping for primer.. This will protect the metal from futher rusting until I'm ready, even being outside.
 

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#4 ·
Great job so far, can't wait to see more! I've used something from the hardware store called "The Must for Rust" that is similar, probably a watered down version of Ospho. Now that I know what to look for an where, I'll use Ospho instead!
 
#7 · (Edited by Moderator)
Old Fool said:
In the quest to get er dun, why not first hit it with the da, then the Ospho?

I like to let power tools do most of the effort, if that works with your process..
In this situation,(surface rust), sanding wasn't necessary before applying the ospho. In the video it shows just how quick it works..
.However in extreme cases It will be necessary to sand or wire wheel the surface first. Coming up, is a car that had a vinyl top that is extremely rusty with pits but I'm saving the best for last....Bear with me..
 

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#268 ·
Mike I went back through the thread but never did see where you did this heavily rusted vinyl top car. Do you have pictures of it?

...........but I also remove the black from the heavyrust with a wire wheel and reapply until the rust spot stops turning black...so I'm removing the rust not converting it...it dosent say anything about that in the directions either....But keep in mind the automotive industry only accounts for 1% of it total sales its mostly use for big projects like metal roofing and those big water towers ,mostly people buy it 200 gallon s at a time...its been around forever...As faras neutralizing with water goes ,all I can say is I never did it like that, I just sand or scuff then dewax...
Brian, If I understand Mike's post correctly, he is not advocating painting over the black converted rust but rather retreating until there is no more black and all the metal is silver with the rust REMOVED!

That would account for his success since the rust is no longer lurking under the surface.

That leaves the proper cleaning to be done, whether it is by sanding or washing to make sure there IS NO ACID under the epoxy to effect it's curing and proper adhesion.

John
 
#8 · (Edited by Moderator)
If you decide to strip the old paint from your car and start fresh,I'd suggest stripping the whole car at once and then working one one panel at a time priming each panel as you go.
This takes time and your car will start getting surface rust,so what I do is apply the Ospho to the whole car immediately after stripping it really doesn't matter what method of stripping you use ,media blasted ,sanded or chemical strip,etc...here's a short vid of the prep process.http://www.streetfire.net/video/prepping-metal-for-oshpo_1028571.htm
Ospho can be a big help getting the steel extra clean and keeping the bare metal from rusting until its primed,it leaves a protective primer coat when it drys.This hood had very little rust at all but I'm doing this outside so as soon as I got it stripped, sanded and cleaned I applied the ospho because I couldn't immediately prime the steel...http://www.streetfire.net/video/applying-ospho-to-unrusted-steel_1026717.htm
Reason: I don't like mixing small amounts of primer,I'll wait until my motor cycle tank is ready and then I'll prime both at the same time....
 
#9 ·
Sometimes if there's to much excess left on you'll see streaks like this.I like to reapply a second coat... just repeat the process (see pics below).
Lacquer thinner wont remove them and they must be sanded before priming I just apply a second coat and forget about them,I'll get more into that later.(Prepping for primer)
 

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#11 ·
That's basically the directions I recall from "The Must for Rust". If there is a lot of white residue after drying, apply another coat, let sit for a few minutes but DON'T let dry, then rinse off. The acid will soften the residue and the excess will rinse off. A small amount of residue is just prepped over. I'll wait for deadbodyman to describe the pre-prime/paint procedure -- I have to admit I've forgotten!

If you just want a bit to try see if the local Ace hardware doesn't have "The Must for Rust". I've bought it at K-mart too. A lot cheaper than the Ospho, but it's a bit weaker too. I bought it in a ready to use pump bottle. It's basically the same as Ospho, just weaker for the DIY homeowner, not professionals. Other than that all procedures are the same. Read directions on the label!
 
#12 ·
DBM, you don't rinse this with water after application?

I used Metal Ready on some minor rust once on my van before epoxy and SS. 2 months later I noticed the paint bubbled in the same area's I used the Metal Ready, no where else. That was a year and 2 months ago, now I have rust spots all over the Metal Ready area. Shortly after this happened I read on the SPI forum about this exact problem being caused by acid metal treatments.
So now I am a bit gunshy about using any type of acid.
I was careful to rinse the acid off before it dried, what did I do wrong?
Have you ever had this problem with Ospho seeing its an acid?
 
#13 ·
All I've ever used has been Ospho.I've never rinsed it off or touched it with water I just let it dry.the heavier spots where you see the streaks stay tacky longer than the rest and if you were to prime over them while tacky, I'm sure there would be problems.
When I'm ready to prime, I just sand with a da or scuff pad and wipe off with wax & grease remover.I'm pretty sure I'll be priming tomorrow so you'll see the whole process.

The way I do it is not quite the way the directions say but I feel it's even better.
After the primer has cured ,I'll do some adhesion tests.
My little shop truck was stripped and painted using the same method,well over ten years ago and still looks like its fresh paint.I'll post a few pics of that too.
Please keep in mind there's many acid products out there.This is just, about Ospho,I have no idea about any others,including Naval jelly.
 
#15 · (Edited)
Chas350,You can do it either way.
On exposed surfaces that 'll be painted ,I sand the coating to give the epoxy something to bite into but I dont sand it off. I do sand a little extra to remove the rough streaks left by to much excess
.On other areas that wont be exposed (like wheel wells inner rockers etc) and irregular surfaces like door jambs... I scuff insted of sand..
Once your ready to prime,you can sand All the coating off if you like,its already done its job protecting against further rust.
Heres the video showing how I sand with 180 then wipe off the grayish powder with wax & grease remover then prime.The glare is bad but you can see how little time it takes to prep. http://www.streetfire.net/video/prepping-ospho-for-primer_1411477.htm
Today I'll sand and prime the other side of the hood without Ospho and do a couple of adhesion tests on both sides when everything is cured. Then it's on to the real heavy rust on that Furys roof
 
#16 · (Edited)
Unexpected test results

Today the epoxy was cured .......To test it, I stuck my fingernail in it to see how hard it was, my nail couldn't catch hold so it was ready.
I started by putting a blob of bondo on unsanded epoxy primer and stuck two pieces of 3-M duct tape on the hood.
I pulled the tape of quickly and the primer stayed.showing some pretty good adhesion of the primer to the Ospho treated metal.
Then I got my three point putty knife placed it at the base of the blob of bondo and whacked it with a hammer...to my surprise the bondo split leaving a small amount still on the hood.
Then I tried scraping it off,some more came off but I had to sand the rest to get it all off.
After I sanded the bondo off I stopped so you could see the primer still there.
If you look close, after I sand the bondo off you can see the Ospho coating still there ,it looks like an e-coat at the edge of the shinny sanded metai theres a grayish ring just before the black primer.http://www.streetfire.net/video/ospho-adhesion-test-epoxy-primer_1472412.htm .
I always sand the primer before I start applying the bondo.I really thought the bondo would come clean off the primer but as you can see bondo sticks to unsanded primer extremely well.I was surprised and impressed to say the least.
I'll still sand before filling but its not really necessary.
I primed the other side of the hood after all this ,and We'll test the untreated side as well, but as far as primer having adhesion problems with Ospho ,Clearly you can see its not an issue when done properly.
I'll entertain any other thoughts on tests anyone would like done if there are any other ideas.
Next,I will be treating some seriously rusted ,pitted steel on that fury roof.
 
#17 · (Edited)
Sparky,
There are many ways to get a job done. As a young apprentice I was taught this method by an old timer. I've been using it ever since (over 25 yrs).I've always worked in shops that restored all kinds of autos and built drag cars,(Even met "Big Daddy" a couple times) ..
The man that taught me this ,worked at restoring rare, high dollar, cars for museums for years.
Sometimes sandblasting is NOT an option,mostly because of the mess ,the abrasives get everywhere ,in every nook and canny in the shop even with a booth its still gets spread around the shop.
Most body shops I've ever worked at don't do blasting at the shop and send that work out....That's what I would suggest doing if anyone has there heart set on media blasting,unfortunately, its expensive and requires a pro to properly strip a car and there's no guarantee it'll still be straight.(I prefer chemical stripping)
Then, when you get your car home you need to protect the bare metal right away with epoxy primer. Unfortunately,it takes time to properly prepare a car for primer.two to three times longer for a DIY... I
t doesn't matter what method you use to strip your car, Ospho will protect bare metal from surface rust for many, many months, I always apply the Ospho IMMEDIATELY after exposing the metal.Its been suggested and agreed upon that getting the epoxy on immediately is the proper way to go and no one should trust a sandblaster to prime their car properly, its a completely different trade.
So, this is how I start a resto,chemical strip and Ospho,its another option to letting your car get all rusty or after paying a small fortune getting it blasted,Letting it sit and rust is going backwards.
Any body can apply Ospho to a complete car in LESS than an hour,(longer if if it has rust) and you'll be in no rush to prime for months.
Even if it has no rust at all, it can still be used.This is the main advantage of using Ospho but there are a few more.As far as I can tell, nobody questions it's ability to remove rust or etch metal,the problems start with getting primer to stick to it, that's never been a problem for me ,so I decided to show how I do it and how easy it is to apply and then do a few adhesion tests to show, when properly done its not an issue.BUT...if anyone is a little leary ,you can always sand it off one panel at a time and work that panel ,prime and move on to the next. Always epoxy prime before doing any body work ,Bondo will not stick to Ospho....Also,if anyone has used Ospho and had problems this would be the place to ask about it and find out why.Its one of my favorite products and should work well for anybody.
This is simply my attempt to end all the misconceptions caused by misuse of a good product,by someone that uses it..... I'd do the same with ANY of my favorite products,if the use of them were to be disputed......One of the popular questions in the forums is ("My car has been blasted and its rusting,What can I do") ....
I'd like to add that in most cases, everyones opinion is welcome but in this case all the opinions have only added to the confusion so this is my attempt to back up my opinion with facts and end the confusion....any advice on how to better accomplish this would be welcome and recieved in the sprit it was intended........Thank You.........
.Mike O.
 
#18 ·
Today ,after letting my old hood sit for another week,I did all of the same tests to the other(untreated) side plus redid the bondo blob again.
I added another test used by the military that another member told me about....


page 54 on this link is instructions for how to do a cross hatch cut adhesion test...

https://www.oskgpsc.net/otc/paintspec.pdf

(a shortcut direct to the page is back space/blank out the pdf page number window at the top and type in "54" and hit enter on your computer)

...This test involved scratching lines through the primer all the way down to the metal,making nine squares.
I did this to both sides of the hood...Remember,one side was treated with Ospho and the other side was just sanded with 80gt da.Then both sides were cleaned with wax & grease remover and primed with epoxy.
I was told that masking tape would work fine for this test but I really wanted to put this to the test so I used duct tape again because it sticks way better than masking tape.Heres the pics of how I did it.
 

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#19 ·
first I layed down two strips of tape over an untouched, primed surface and pulled them off,just like I did to the treated side a few days ago.
Then,I covered the nine squares with with two strips of duct tape and pulled them both at the same time. then chiesled off the bondo.Heres the video....http://www.streetfire.net/video/adheasion-test-military-type_1994959.htm
Again , I was very surprised at just how well the epoxy stuck to untreated metal..The SPI epoxy stuck every bit as well to untreated steel as it did to the treated steel I truly thought I was going to pull the primer right off the untreated steel.As far as I can tell, so far the ospho treated steel passed the adheasion tests with flying colors,and I'm even more impressed with SPI epoxy than I was before....and I loved it before...In a couple days I'll get started on that roof and show you just what this Ospho can really do with rusted metal.BTW if there are any more suggestions for more tests please let me know.
mike O.
 
#20 ·
DBM, is there any gaurantee ( you ) can make as to the life expectancy of a treated OSPHO Panel? Doing it your way , or if you did the work , how long can you gaurantee that rust will not prevail in the treated areas? Since you believe so STRONGLY in OSPHO, and if you were to do a customers car , can you warranty the treated Ospho area from rust appearing under the paint? Believe me i am watching this with great interest. I have some rust issues with my next project that i will have to attend to . I commend you for your strong dedication and determination to prove your respect for the product. My hat's off to you . A friend awile back had his 66 GTO painted and there was rust in the rear quarter panel, i dont know how the body man took care of it , but three years later , rust was forming under the paint. Regardless, i just want to know if this is a ( aslong as you own the car ) or if there is some sort of time frame here? I never used any of these acid products so i dont know ??????? Once again , i think what your doing is great , and it tells me more that whats written on the back of a can or bottle to actually see someone apply his knowledge and trust of a product set fourth in proof.
 
#21 ·
CB,check the dates in post#39,LOL... the 1/4 as really been done for 5-6yrs unpainted just epoxy and its outside most of the time.not even the slightest sign of rust.
I guarantee my rust work for five yrs but it has to be brought in when it starts ...so far Ive never had one come back.

I've seen one car I restored for a friend in Fla. ,(a 69 camero) about twenty years ago and it looked like it was a year old paint job,but he took good care of it and keep it in the garage when he wasnt driving it..that makes a big difference.
The way I look at it ,On the east coast cars can rust within five yrs when new, so anything over that is great.
You got to remember with heavy pitted rust there isn't much metal left.the best thing is to replace it.(but that gets expensive) or clean up the rust (like my trim holes) and glue some metal to the back side for strength.
can you see the patch covering the holes from the inside? (the first pic below) I made the bottom of the 1/4 myself.It would have taken less time to replace the1/4with a good one but I couldn't find one plus the ones I found out west were to expensive I would have had to replace the whole body ,then I wouldn't want to make all the changes to the things I didn't like.Like the taillights and everything from them down.Working with metal is a lot of fun.I made the whole bottom 12" of the car by hand rockers and all.the roof was rotted with holes I repaired that with Ospho too its been two years now and still looks great but some day it'll start rusting again...it has to... its just the nature of metal to return back to its natural state.
But....I built this car with less than a 1,000.00 in cash and did most of it in my driveway... Dont ask how many hours .. I dont have a clue. I did it for fun.

Dont get me wrong Ospho wont solve all your rust problems.
any rust on the lower 12" of your car should be replaced with new metal but above that repairs will last a lot longer.
For example: if you have a rust hole at the front and back corners of your door ,chances are, the middle will rust out shortly to so dont waste time fixing that replace the whole door bottom.same with the rockers...

I guarantee no shop would fix my car at any price ,you have to enjoy this kind of work to do it.I wouldnt do this much work for anyone either.
I will admit I'm tired of working on this car and all I want to do is drive it now.I wont be painting it until next year...
Then ,I'll give it to my son........Maybe ,at least thats been the plan all along.....
 

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#22 ·
BarryK said:
A while back in the other threads I posted what the acid film will do to three different chemicals, related to just three different products,
OK, let's say I've inherited a project previously Ospho treated. What can be done to neutralize it before priming? Replacing a car isn't an option, there has to be something that will kill the acid.
 
#24 ·
"Replacing a car isn't an option, there has to be something that will kill the acid."

Free oxygen in the atmosphere will neutralize the acid. You could:

re-apply with Ospho
first rinse with 'sudsy' ammonia and water to neutralize
second rinse with clear water until clean
dry well
heat the panels above room temperature
prime

moisture condenses on sheet metal exactly the same way as an iced-tea glass and autobody products are petroleum based, they float on water. You really do need the get the moisture out of the pores of the metal if you want the job to last.
 
#25 ·
KMatch said:
OK, let's say I've inherited a project previously Ospho treated. What can be done to neutralize it before priming? Replacing a car isn't an option, there has to be something that will kill the acid.
IF that was me, I would wash twice with Purple Power with a pressure washer and give a good hot water pressure water rise after each washing.
 
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