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Barry,

All great information I appreciate you taking the time to add your input. the question still lingers in my mind, however, is it possible that Ospho being applied to ONE SIDE of a slightly rusty panel would lift the cured epoxy primer (via pinholes etc) that was sprayed on the other side of the panel a few days/week prior?
I'm pretty sure I've taken care of my problem this time, but it would still be helpful for others to know.

Thanks again Barry,

Russ
Not really possible as epoxy does not have a sensitivity time, like clears do, now with that said, there are 100's of epoxy resins to start the formulation with and I don't know all of them but just seems unlikely, all it would take is a small pin hole left where vapors or water could creep through and then you would get a gassing type bubble.
Easy to miss these pinholes as I have done it over the years, along with all other body-men if truth is known.

Some epoxy's are strong enough to repair these holes but not with spraying.
I have been burnt twice over the years with SL280 and SL260 doors, so with the door sand blasted (inside and out) when I can't see the pinhole I put duct tape on out side and with door flat I pour epoxy on inside and two or three times over a days time I tilt the door to let the epoxy get in all the creases and pits, then UN-tape a drain hole and let epoxy drain into a painters pail so I can use leftover in other door.
This has worked so well for me, I even do it ob the old vettes, gives me something to do, if nothing else.
You just can't always see the fine pinhole.
 

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OK, I have to correct myself, I have done some research on this and I must change may answer to could have happened.
What I was told is there are a few epoxy resins that will do this with acid, even if 6 months old.
I was told of a couple of companies in the automotive refinish section that use these but that don't mean there not blended to not do it, could be but anyway to answer your question YES it could have happened.

Sorry for the bad info.
 

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Discussion Starter · #23 ·
OK, I have to correct myself, I have done some research on this and I must change may answer to could have happened.
What I was told is there are a few epoxy resins that will do this with acid, even if 6 months old.
I was told of a couple of companies in the automotive refinish section that use these but that don't mean there not blended to not do it, could be but anyway to answer your question YES it could have happened.

Sorry for the bad info.
What are you saying Barry? you're human?? :D:D

Are you familiar with Montana brand Epoxy Prime PS3044?? that's what was used on my 59 (local jobber).

Thanks,
Russ
 

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What are you saying Barry? you're human?? :D:D

Are you familiar with Montana brand Epoxy Prime PS3044?? that's what was used on my 59 (local jobber).

Thanks,
Russ

Russ,
I really know nothing about the Montana epoxy except they are owned by Metalux out of Africa.
Even if I did it would not be proper for me to discuss here.
Everything or problem has a time line and with a true time line we can pinpoint where the problem is coming from, example is solvent pop with clear, if first coat can be 4 or 5 different things, 2nd coat 2 or three different things, overnight, one thing and 2-5 days later a couple of other things.
I will give you a few time lines and then you can figure out what may have caused the problem.
If acid attacked the epoxy, it would have looked like a wrinkle or softened it in about 3-15 minutes.
If the bubble appeared in a week or two being inside the whole time if may have been a Co2 gassing, outside in sun this could have happened in a few hours or a couple of days.
My GUESS!
Remember Ospho has water content of somewhere between 40 and 60% from what I remember.
So I would suspect one of the following happened.
If you neutralized, water got in the pit and with less air flow in the pit it was not dry and the epoxy sealed it and it started rusting and caused the gassing.
Next thing that could have happened is wax and grease remover was not dry in the pit and it will do the same thing.
The result of the above would be a bubble that is soft and sometimes if you push it will go away but return shortly.
High humidity and time are a big factor here and it’s the same as cleaning the inside of a car as it does not get the airflow as an outside panel will.
 

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Deadbodyman. I need to ask you several questions about Ospho. I can call you if that would be better.

I ended up applying OSPHO everywhere on my car/utility trailer this past Friday night. It had been sandblasted this week. All day Saturday, there was no rust anywhere that I could find. When I woke up this morning, it is now covered in surface rust. What are my options to get this thing ready for primer and paint. Mind you, this isn't going to a show piece. Just used for hauling hunting, camping supplies, riding lawnmowers, 4 wheelers, etc down dirt roads and the brush. Can I just use a rusty primer to get it ready? Or do I need to reorder a gal of OSPHO as I am now out, and redue the whole thing over?

Thanks.
 

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Brian Martin,Freelance adviser
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There is nothing but nothing better than sandblasting and then epoxy primer. There was nothing better that you could have done. Now, I say have it sand blasted again. With all the nooks and crannies that the Ospho could caught in, I say wash it good with water and blast it again.

Brian
 

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SPI Thug
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phosphoric acid is one of the best cleaners available . used correctly it will clean metal very well . as long as it is rinsed while wet it is no problem . after cleaning you will see an orange tint on the metal . this tells you it is clean .
 

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So after posting the earlier message I started calling around for some more OSPHO. There wasn't any around for 50+ miles, so I had to order a gallon.

Needless to say, I decided (since I hadn't heard anything back yet) to get a wire wheel out and get as much rust off as I could. That way it would at least slow the rust down till Wednesday (as I took the wifes SUV out of the garage and moved the trailer in), and I can recoat it then.

So after wire wheeling the whole trailer but the inner fender wells (no rust) and wheels (buying new ones), it looks much better. I think in the long run I am glad this happened. As I found a lot of black parts (converted rust) that I was able to remove. Now the trailer is the grey color it was before it rusted over night. Granted you can still see some rust bleed through. Or at least I think it rust bleed through?

My next question is: can I just go ahead and use oil based Rustoleum primer product after I use Prep All? Or do I need to wait and wash it again in OSPHO?

Thanks for all the help. Especially since it's just a trailer and not car/truck.
 

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After spending hundreds of hours building my 59 BelAir, it was really hard for me to take a knife to the paint, but Today I finally drummed up the energy to chip off this D*** blister on top of the fin, below the B pillar. I was pretty sure of what I would find, and it's now confirmed that the Ospho that I sprayed inside the fender caused this. I carefully lifted the blister off so I could see exactly what was under there and where the separation occurred. as you can see, there's lots of the black powered remains of Ospho. I repeat, there was NO Ospho applied to the outside sheetmetal anywhere on this car. the only reason I applied it inside this area was due to the almost total lack of access by any means short of dismantling the inner sheetmetal structure in that area, and there was some surface rust that I felt the need to "kill". the Ospho was sprayed inside well after the Epoxy was sprayed on the outside. it appears clear that some Ospho found it's way up through three pinholes in the sheet metal. when I sprayed the epoxy it was applied to well cleaned shiny metal.
I've spot blasted the area and am in the process of repainting. I'll blend the base and clear the whole top of the fin. my only concern now is if this will reoccur. I'm sure there are places that Ospho can be used to good advantage, but I'm not smiling on it at the moment. :nono:

Russ
what you did when you "sprayed it on well" is convert the rust.
rust converting is no good, you want to REMOVE the rust. Ospho removes rust but its a lot of work ,what you did is the same thing a lot of people do they spray it on like its some kind of magic solution and just leave it ...THEN when the problems pop up that everyone warned you about you blame the product ,it couldn't possibly be improper application,I did it all myself...:nono: listen to the pros that use it or don't use it at all. at least you've learned something.(the hard way) ...lesson #1 improper application of acid products are the #1 cause of paint failure....
 
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