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Old 06-20-2011, 10:18 PM   #1
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Epoxy over Ospho?

I have replaced some body panels slowly. I had spots down to bare metal and to keep the from flash rusting I coated the with Ospho. My question is do I need to neutralize them before Epoxy and if so how do I do it?
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Old 06-21-2011, 09:23 PM   #2
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Re: Epoxy over Ospho?

I guess no one uses Ospho?
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Old 06-21-2011, 09:58 PM   #3
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Re: Epoxy over Ospho?

You will not need to neutralize, although ive heard bad things about epoxy over Ospho. Do a search I remember a thread here about this very thing.
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Old 06-21-2011, 10:52 PM   #4
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Re: Epoxy over Ospho?

You would need to check with your epoxy manufacture, check out the products tech sheets, it will tell you want you can and can not apply over and under the epoxy.

Not all epoxies are the same so don't take blanket answers for truth concerning all epoxy primers.

But typically epoxy primers and metal treatments do not work well together...Eric
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Old 06-22-2011, 11:38 AM   #5
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Re: Epoxy over Ospho?

If you are putting epoxy over ospho you have to use epoxy that dosen't contain acid.
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Old 06-22-2011, 07:29 PM   #6
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Re: Epoxy over Ospho?

I contacted SPI and they told me to activated it again by reapplying Ospho and rinse with water before it dries. Dry good and wipe down with W&G remover and paint.
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Old 03-19-2017, 09:29 PM   #7
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Re: Epoxy over Ospho?

From their website...

RUSTED METALS - OSPHO is a rust-inhibiting coating - NOT A PAINT You do not have to remove tight rust. Merely remove loose paint and rust scale, dirt, oil, grease and other accumulations with a wire brush - apply a coat of OSPHO as it comes in the container - let dry overnight, then apply whatever paint system you desire. When applied to rusted surfaces, OSPHO causes iron oxide (rust) to chemically change to iron phosphate - an inert, hard substance that turns the metal black. Where rust is exceedingly heavy, two coats of OSPHO may be necessary to thoroughly penetrate and blacken the surface to be painted. A dry, powdery, grayish-white surface usually develops; this is normal - brush off any loose powder before paint application.

NEW METALS - For new ferrous or aluminum metals: remove dirt, grease, or oil; apply OSPHO, let dry overnight, then paint.

Ive done my build 85% with this stuff and as long as you follow the directions, outcome its great!

Only 85% not 100% was becausei found about product between projects while doing my cab rebuildand now finishingmy bed ...
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Old 03-20-2017, 09:13 AM   #8
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Re: Epoxy over Ospho?

They also hide this on their website:

"Test a trial sample before using under epoxy or latex-base paint applications."

Most people don't see or read that.. Their little disclaimer to eliminate product liability for when your epoxy starts to delaminate. If you want to see if your paint is compatible with Ospho, check with the paint manufacturer; don't rely on a sales pitch from the Ospho web site..
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Old 03-20-2017, 09:24 AM   #9
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Re: Epoxy over Ospho?

Old thread warning.

Technically speaking, epoxy is not paint. It is a corrosion resistant coating designed to only stick to clean, abraided bare steel.

Mess with this proven product/process, you run the chance of a failure. Not me!
So when is this "Old enough to know better" supposed to kick in?

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Old 03-21-2017, 10:31 PM   #10
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Re: Epoxy over Ospho?

This guy has a good video explaining the steps, I truly believe ospho is great, I use it on every thing that has rust, I wire wheel the area , ospho it, then scotch bright it, then ospho it again, after having watched the video I now try to re activate it and clean it off, , here is the link, the second and third video shows the results,
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Old 03-22-2017, 05:33 AM   #11
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Re: Epoxy over Ospho?

I learned this the hard way, trust me it was awful. It almost appeared as if I added oil to my epoxy. I wouldn't even attempt it. Luckily mine was just the inside floorboard where you wouldn't see it. It was full of fish eyes

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