How to neutralize Ospho

shine said:
consider the source. rinse while wet . period .
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I see you're an advocate of using water and dawn to rinse but how do you not have a light layer of rust form after that? I dont think i could get all the nooks and crannies completely dry.
 
Sorry if this is covered and I missed it, or maybe I'm just not following.

I have an under body panel that I stripped down and sanded as much as I can. It's pretty rust free now minus some rust pits that I can't really get to. I'm planning to use Ospho to get in to those pits and then follow the neutralization process you described. Will the SPI epoxy primer adhere to the iron phosphate that's left behind after neutralization or will this fail?

Thanks!
 
I'll explain how to neutralize again. Follow these steps and you will have success. When you are ready, re-wet the panel with Ospho. Keep it wet with Ospho for at least 10-15 minutes. Do not let it dry. Very important. While it is wet you can take a wire brush or scrub pad to the panel to help clean off any gunk. After it has been wet for 10-15 minutes, rinse well with water. You may get some flash rust, that is OK and can be primed over. If it bothers you you can go over the panel with a DA (80 grit) or hand paper to remove it. Then prime as quickly as possible.
 
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I get that part. My concern is more with the rust pitting. There is tiny bits of rust left in the pits that I'm not able to clear out. If I spray with Opsho, and follow the proper neutralization technique should I expect the rust to grow and rear it's ugly head in a couple of years?
 
FourCuteCats said:
I get that part. My concern is more with the rust pitting. There is tiny bits of rust left in the pits that I'm not able to clear out. If I spray with Opsho, and follow the proper neutralization technique should I expect the rust to grow and rear it's ugly head in a couple of years?
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Media blast it for best results. Use a spot blaster on the pits if you don't have access to a blast unit.

Don
 
FourCuteCats said:
I get that part. My concern is more with the rust pitting. There is tiny bits of rust left in the pits that I'm not able to clear out. If I spray with Opsho, and follow the proper neutralization technique should I expect the rust to grow and rear it's ugly head in a couple of years?
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The mere presence of rust isn't something that makes more rust, it requires oxygen and water to catalyze that reaction. So if you cut these off...
 
FourCuteCats said:
I get that part. My concern is more with the rust pitting. There is tiny bits of rust left in the pits that I'm not able to clear out. If I spray with Opsho, and follow the proper neutralization technique should I expect the rust to grow and rear it's ugly head in a couple of years?
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The pits can hold rust scale as well that is about impossible to remove unless using a spot blaster or similar method. My first experience with Ospho was owner applied and his buddy used it all the time with no problems, so it was all good.. NOT!!!


MP&C said:
One of my first overall paint jobs was wasted because the owner had done the bodywork on his Model A, applied far too much ospho and did not remove any residue from the deep pits. My first experience with ospho, and questioned it as my gut told me this wasn't good. But it was OK, because his buddy did it all the time and had no problems, so he said. Once painted and the car sat in the sun at all the car shows that year, the ospho collected in the pits activates and the chemical reaction starts outgassing. So what that looks like is little tiny circles of paint lifting. In less than a year. So my advise is that what you've been told about a spot blaster for cleaning out pits is on the money, and f**k what anyone's buddy says, get your advise from the paint manufacturer that made what you're spraying on the car. If you look up companies like Ospho, their website will proudly proclaim that it works with all paints, and then hides the disclaimer of suggesting you spray test panels on another page. Snake oil salesmen are in the business of selling snake oil, they could care less what peels. Get the correct info from your paint company.
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Lizer said:
The mere presence of rust isn't something that makes more rust, it requires oxygen and water to catalyze that reaction. So if you cut these off...
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That is true, but if scale rust is big enough, it will hold moisture and air in the center.
If you slice it in half with a single edge razor blade under a microscope, it will look like the ledge rock you see on the side of an expressway
Where they used dynamite to build the road.

Years ago, I found a big one on a fender; I carefully slit it in the center a put a drop of a PTSI on it and it exploded because of the amount of water and the bracing of the metal on the sides; that is why you wear goggles when you do dumb things like that.

PTSI is an isocyanate moisture scavenger
We use them to treat solvents and used in activators to extend their life.
 
pits are not your friend. those little bastards will come back as pimples . i have taken a 60 grit disc to a panel to get rid of them.
this is why i love starblast . it is fine enough to get the pits clean . only way i know to get rid of them.
 
After applying Ospho, the rust pits will turn black as it converts the rust to iron phosphate. Which is inert, but that’s only the top layer. So many guys think it’s “good” at this point for primer. But take a sharp scribe and dig that black stuff out, and brown rust will more than likely be underneath. This is why blasting is so important.
 
Barry said:
That is true, but if scale rust is big enough, it will hold moisture and air in the center.
If you slice it in half with a single edge razor blade under a microscope, it will look like the ledge rock you see on the side of an expressway
Where they used dynamite to build the road.

Years ago, I found a big one on a fender; I carefully slit it in the center a put a drop of a PTSI on it and it exploded because of the amount of water and the bracing of the metal on the sides; that is why you wear goggles when you do dumb things like that.

PTSI is an isocyanate moisture scavenger
We use them to treat solvents and used in activators to extend their life.
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Next time dip that entire sucker in water before adding the PTSI to it. And be sure to record it for us. Lol.
 
Previous posts have basically said that Ospho film residue is an enemy of epoxy paint.
But, not all epoxies are the same, so ....
Is Ospho film residue also an enemy for JB Weld original steel reinforced epoxy?
I'm using the JB Weld to repair a rust hole. I already used Ospho to neutralize the rust, and I'm trying to determine the next step.
I have seen that some people do nothing after the Ospho, and others neutralize it.
I wonder what applies best in this situation?
 
You'd really have to ask the JB Weld people about acid residues, but as far as I know, their product likes clean abraded metal the best. Here's the Ospho neutralization instructions from the SPI tech manual:

Neutralizing Skyco Ospho:
Ospho is the only rust treatment we recommend IF needed under epoxy primer. Apply Ospho as needed and leave it on as long as you like. When you are ready to neutralize the dry Ospho, apply one more coat of Ospho over the area to be neutralized and let it set for 5 minutes. Using a clean towel and water, wash off the wet Ospho like you are washing a car then dry with a clean towel. A dry acid film cannot be neutralized or sanded off.
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Tuxedo said:
Previous posts have basically said that Ospho film residue is an enemy of epoxy paint.
But, not all epoxies are the same, so ....
Is Ospho film residue also an enemy for JB Weld original steel reinforced epoxy?
I'm using the JB Weld to repair a rust hole. I already used Ospho to neutralize the rust, and I'm trying to determine the next step.
I have seen that some people do nothing after the Ospho, and others neutralize it.
I wonder what applies best in this situatio
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Dont leave us hanging. Please give us the name of one epoxy in automotive refinish that works over an acid film.

I trust you are not saying jb weld is the same as Automotive epoxy?
 
Barry said:
Dont leave us hanging. Please give us the name of one epoxy in automotive refinish that works over an acid film.

I trust you are not saying jb weld is the same as Automotive epoxy?
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I think he's asking does he need to neutralize the ospho to use the JB Weld?
My thought would be that it's necessary.
 
Barry said:
PTSI is an isocyanate moisture scavenger
We use them to treat solvents and used in activators to extend their life.
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I'd never heard of PTSI's before, I'm not a chemist which would explain that. :)
Looked it up and it's some interesting stuff. VanDeMark

John

"The reactivity of PTSI toward active hydrogen atoms makes it useful as a scavenger for water and other isocyanate reactive groups such as free acid in powdered aluminum alkanoates and active hydrogen present in carbon black pigments which cause polyurethane coatings, sealants and adhe‐ sives to thicken during storage"
 
Chris_Hamilton said:
I think he's asking does he need to neutralize the ospho to use the JB Weld?
My thought would be that it's necessary.
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My concern was all epoxies are different
And i dont want a newbie getting confused and redoing a job as i had a couple of weeks ago when he followed the directions on an Eastwood label.
Funny, this was the tech guy who told him well, some say you must neutralize it, and he said his response was, that's not what your label says.
Well, that and a dollar will get him half a cup of coffee.
 
Chris_Hamilton said:
I think he's asking does he need to neutralize the ospho to use the JB Weld?
My thought would be that it's necessary.
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^This.

As in 'JB Weld is an epoxy, but it's not the same kind of epoxy as an epoxy primer, so do the Ospho rules still apply?'

To answer Barry's question, I see a lot of people using Kirker over Ospho.
 
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