TheSamba.com :: View topic - POR-15 over ospho (or equivalent)

Mon Jun 07, 2010 6:38 pm

The directions on POR-15 say not to use a rust converter such as ospho (I assume this is because the converted rust will let go easier and weaken the bond of the POR-15?). I have used some ospho on my current project, but plan on final coating with POR-15...what has ya'll's experience been? Is it simply a matter of wire brushing thoroughly to get ALL loose material off and then coat? Or is there a better method.

Thanks

Mon Jun 07, 2010 7:35 pm

I would just not use POR15. Knock the scale off with a scotchbrite and topcoat with epoxy primer. But keep in mind epoxy must be topcoated with 2k and there is a recoat window with epoxy.

If you are dead set on using POR15, I would sand off as much of the Ospho as you can.
I belive that the problem with Ospho and POR15 is the acid in the Ospho reacting with the POR15. Maybe once you sand it, you could nutralize the Ospho with water, just be damn sure you get it dried really well.

Mon Jun 07, 2010 9:23 pm

Por-15 actually has a substrate rinse that it sells and recommends that is, by description, ospho.

I've never seen this ospho product. But it reads that its just an acid and zinc phosphate (i think) solution. Same as por-15's "metal ready" i think its called.

Is ospho the exact same thing as jasco prime and paint (green rust blackening solution)? Is it a one off product? I can't get it locally, it seems to have 2 or 3 super fans out there in the forum. Their web site reveals nothing of interest.

Tue Jun 08, 2010 2:41 am

zeroman wrote: Por-15 actually has a substrate rinse that it sells and recommends that is, by description, ospho.

I've never seen this ospho product. But it reads that its just an acid and zinc phosphate (i think) solution. Same as por-15's "metal ready" i think its called.

Is ospho the exact same thing as jasco prime and paint (green rust blackening solution)? Is it a one off product? I can't get it locally, it seems to have 2 or 3 super fans out there in the forum. Their web site reveals nothing of interest.

look for a product called prep and etch
HD sells it here

Tue Jun 08, 2010 7:13 am

spook wrote: zeroman wrote: Por-15 actually has a substrate rinse that it sells and recommends that is, by description, ospho.

I've never seen this ospho product. But it reads that its just an acid and zinc phosphate (i think) solution. Same as por-15's "metal ready" i think its called.

Is ospho the exact same thing as jasco prime and paint (green rust blackening solution)? Is it a one off product? I can't get it locally, it seems to have 2 or 3 super fans out there in the forum. Their web site reveals nothing of interest.

look for a product called prep and etch
HD sells it here

Got a link? I dont know who HD is? Can filler be applied over prep and etch? Can he apply over Ospho, or is it a replacement for Ospho (or like products)?

Really the only good thing about Ospho is that it is easy to get (Home Depot etc..). I personally rather use Picklex, but it is expensive and most guys wont use it because of that.

Tue Jun 08, 2010 8:30 am

buguy wrote: spook wrote: zeroman wrote: Por-15 actually has a substrate rinse that it sells and recommends that is, by description, ospho.

I've never seen this ospho product. But it reads that its just an acid and zinc phosphate (i think) solution. Same as por-15's "metal ready" i think its called.

Is ospho the exact same thing as jasco prime and paint (green rust blackening solution)? Is it a one off product? I can't get it locally, it seems to have 2 or 3 super fans out there in the forum. Their web site reveals nothing of interest.

look for a product called prep and etch
HD sells it here

Got a link? I dont know who HD is? Can filler be applied over prep and etch? Can he apply over Ospho, or is it a replacement for Ospho (or like products)?

Really the only good thing about Ospho is that it is easy to get (Home Depot etc..). I personally rather use Picklex, but it is expensive and most guys wont use it because of that.

hd
home depot

Tue Jun 08, 2010 3:37 pm

Ahhhhh! A little slow here in Floriduh

Tue Jun 08, 2010 6:33 pm

I called POR15 today and they basically told me to wire brush it as clean as I could then use their marine clean, then metal ready and coat with POR15 and all would be well...

Tue Jun 08, 2010 9:25 pm

yup marine clean, aka metal prep sol, and metal ready, phosphoric acid and zinc phosphate (think its phosphate). Same thing as any other metal prep.

Wed Jun 09, 2010 4:37 am

I just tried going over Ospho with POR-15 and it didn't stick. The POR-15 separated and doesn't like to adhere to the shiny Ospho surface. I cleaned the POR off with Laquer thinner and will follow the POR instructions.

Ospho leaves a shiny finish where as the POR process ends up with a dull metal prep prior to paint. Theoritically they are both phosphoric acid but the process or ingredients are quite different.

I just don't like the idea of putting water on a metal surface that I'm trying to preserve.

Wed Jun 09, 2010 5:20 am

Using the Master Series products, all I've had to do to apply over Ospho, is scuff the finish that Ospho leaves with a scotch bright pad or 220 grit sand paper.

Wed Jun 09, 2010 9:38 am

I'm not familiar with "ospho" but how can it leave a shiny surface.. nothing sticks to shiny.

Wed Jun 09, 2010 10:32 am

I don't get a shiny finish when I use it. It's more like the look of galvanized metal. Kind of dull actually. But there is a type of film that you need to scuff up.

Wed Jun 09, 2010 10:04 pm

yea.. it should be grey when done. That's the zinc coming out and adhering to the metal. Not the best surface to paint, but best surface to prevent rust. Yea, the ospho doesn't rinse if I've read other people's post's right. Other zinc acid washes are rinsed and dried before hand and I've not had problems with por sticking to them.

If you're rinsing and then scuffing, you're taking off some zinc. Which isn't optimal. Sure you've probably eliminated some surface rust, but you don't need a zinc containing acid to do that.

Thu Jun 10, 2010 7:32 am

Ospho is "supposed" to be rinsed with water. I just cant bring myself to hose off somthing im trying to keep from rusting. What I do when I used Ospho is spray it on a red scotchbrite, scrub it in really good then wipe the excess. Let it sit overnight, then scuff all the scale and crap off with a clean red scotchbrite. Epoxy and 2k after you wipe it down with wax and grease remover.

And I have never seen it shiney either. Like what has been said, should look like galvanized and the rusty parts will turn black.

Thu Jun 10, 2010 10:32 am

buguy wrote: rusty parts will turn black.
b et there is rust under the blk

Thu Jun 10, 2010 2:45 pm

Maybe?? But it seems to nutralize it. Just my experience.

Sat Jun 12, 2010 5:26 pm

spook wrote: buguy wrote: rusty parts will turn black.
b et there is rust under the blk

I know there is. I've used similar products on crap... like railings, lawnmowers, wheelbarrows. And sure nuff, its just an outer coating of black. I've even soaked rust chips in it, sitting in corners of stuff that I didn't clean well. They'd be a black lump in the morning, but break em open, and they're big rust.

I might believe its ok on surface rust, like, flash rust. But it doesn't turn that black, it dissolves it.

Sat Jun 12, 2010 5:55 pm

I think the point is, that it encapsulates the metal and prevents oxygen from reacting with the iron, thereby stopping any further iron oxide reaction from happening.

Sat Jun 12, 2010 6:25 pm

I've been using Auto-Tech Rust-Prep from Grants Pass, OR.