Nailed in plywood

[ChurchBuz]

Originally Posted by EastCoastCB

Paint will stick if you prep the floor with ospho.

Do you leave the Ospho on?

I generally use Ospho as a rust remover/ converter and wash it off after.

EastCoastCB: follow directions on the jug, or do you modify them? If you modify the application, please tell me how.
Cheers

[musigenesis]

I wiped down my Ospho residue (and I had a lot of it) with mineral spirits and a rag, then primed with Rustoleum rusty metal primer, then painted with Rusto enamel. No problems at all with adherence.

On the other hand, I tried spot-painting a couple areas on my floor with POR-15 and Ospho residue completely prevents that stuff from adhering - the paint peels right off like a layer of rubber. POR-15 is overpriced and nasty, I wouldn't recommend it for anything.

[EastCoastCB]

Originally Posted by musigenesis

I wiped down my Ospho residue (and I had a lot of it) with mineral spirits and a rag, then primed with Rustoleum rusty metal primer, then painted with Rusto enamel. No problems at all with adherence.

On the other hand, I tried spot-painting a couple areas on my floor with POR-15 and Ospho residue completely prevents that stuff from adhering - the paint peels right off like a layer of rubber. POR-15 is overpriced and nasty, I wouldn't recommend it for anything.

Overpriced and nasty. Perfect description!

[EastCoastCB]

Originally Posted by ChurchBuz

Do you leave the Ospho on?

I generally use Ospho as a rust remover/ converter and wash it off after.

EastCoastCB: follow directions on the jug, or do you modify them? If you modify the application, please tell me how.
Cheers

If there's no rust and you just want to make the paint adhere to galvanized you can apply the ospho, let it work for half an hour or so, then rinse it off. Once its dry it should be paintable after that. You don't actually HAVE to rinse it though you can just wipe it down and let it dry according to Ospho's site. The rinsing is only really for "visible" stuff like auto body applications. For a floor you can just let it dry, and wipe/brush off any excess after it dries.

GALVANIZED - where appearance is important, apply one coat of OSPHO, let stand for approximately thirty minutes or until metal is etched. Flush with water, avoiding damage to adjacent areas; or wipe to a smooth finish, let dry, then paint. Where appearance is not important, one coat of OSPHO is recommended to thoroughly coat and etch the metal. Let stand overnight or until completely dry. A dry, powdery, greyish-white surface usually develops when cured. Brush off any loose powder and wipe down with Mineral Spirits before painting.

yeah just the normal instructions.
I usually don't rinse it on rust repair I just wire wheel the hell out of it after a healthy coating or two of the ospho.

[TheHubbardBus]

Originally Posted by musigenesis

On the other hand, I tried spot-painting a couple areas on my floor with POR-15 and Ospho residue completely prevents that stuff from adhering - the paint peels right off like a layer of rubber. POR-15 is overpriced and nasty, I wouldn't recommend it for anything.

We used KBS Rust Seal, which from what I've read are pretty much the same thing (both are moisture-cured urethanes, & the internet says KBS is a spin-off of POR, but don't quote me on that). Our results were outstanding.

Part of their 3-part 'system' is effectively ospho - posphoric acid - and their instructions explicitly state it must be rinsed off thoroughly (the other is an aqeuous degreaser, used before the ospho). Other reputable resources (Southern Polyurethanes is one) will tell you their products (not moisture-cured urethanes, but 2K paints) will fail if you don't absolutely, positively rinse off all traces of ospho, while it's still wet.

Not saying this is the case with you, but IMO, many people think their paint sticks when it really doesn't. They put it down, and as long as there aren't immediate & obvious signs of paint failure, they consider it a success. Then - like in the case of a floor - they cover it up, so if the paint does start coming up later, they never know.

Ours... we treated & coated our floor probably close to a year before ever flooring over it. It's had countless tools dropped from height onto it (including a 12" angle grinder from chest height), had constant foot-traffic over it, ladders dragged across it, abrasives ground into it, construction materials loaded in & out over it, you name it. The only place it ever failed/chipped/wore-through? The aluminum strips we never prepped at the stop of the stairwell. I couldn't be happier w/ the KBS. It's tough stuff.

If you're careful with prep & follow directions, you can get close to 2K paint results, at least in regards to adhesion, with their single-stage urethanes. And honestly, if you thin them out right and work fast / in a dry environment, they flow out pretty nice as well. We used their blacktop product - also moisture-cured - for our bumpers. They look damn good, especially for a roller job, and I've already tested the durability by dragging our xterra's bumper across it on accident. Can't even tell it happened on the bus (you can on the xterra )

Here's a thread from SPI regarding neutralizing ospho (& why you should). Well worth the read. The whole thread is a great discussion on the topic from pros that do this stuff day in & day out http://www.spiuserforum.com/index.ph...ze-ospho.3973/

[TheHubbardBus]

Originally Posted by EastCoastCB

You don't actually HAVE to rinse it though you can just wipe it down and let it dry according to Ospho's site. The rinsing is only really for "visible" stuff like auto body applications. For a floor you can just let it dry, and wipe/brush off any excess after it dries. .

I'd trust the manufacturer's recommendations of the paint you use over that of the manufacturers of ospho. Tons of different paint chemistries in the world - the very fact ospho would make a blanket statement applicable to all of them - which I know of more than one manufacturer that directly contradicts - means they have no business giving such advice. If a paint manufacturer recommends you rinse/neutralize ospho, it's not for appearances. It's so it will stick.

[EastCoastCB]

Originally Posted by TheHubbardBus

I'd trust the manufacturer's recommendations of the paint you use over that of the manufacturers of ospho. Tons of different paint chemistries in the world - the very fact ospho would make a blanket statement applicable to all of them - which I know of more than one manufacturer that directly contradicts - means they have no business giving such advice. If a paint manufacturer recommends you rinse/neutralize ospho, it's not for appearances. It's so it will stick.

No paint will stick if you have lots of ospho residue/powder.
What kind of paint are we talking about using on a bus floor? Rusto or some fancy 3 stage PPG?
With rusto you can mop the floor with ospho, let it sit a day or so, wire brush it to get any buildup or residue, wipe it down with mineral spirits, and then paint.
The key is to not leave puddles of the ospho. Apply it then wipe it all smooth.

[TheHubbardBus]

Originally Posted by EastCoastCB

No paint will stick if you have lots of ospho residue/powder.
What kind of paint are we talking about using on a bus floor? Rusto or some fancy 3 stage PPG?
With rusto you can mop the floor with ospho, let it sit a day or so, wire brush it to get any buildup or residue, wipe it down with mineral spirits, and then paint.
The key is to not leave puddles of the ospho. Apply it then wipe it all smooth.

Using a lower price, lower quality paint doesn't make you more immune to problems from residual ospho than some fancy 3 stage PPG. Seems like it would be the opposite if anything (though that's not an accurate statement either).

And the kind of paint we're talking about is the point: You're making generatities regarding paint like it's just one thing, and saying "you can do this or do that" over ospho. It's simply not true. Again there are countless chemistries of paint from countless manufacturers. Many of them I know - absolutely, positively - contradict your advice. Should I listen to them, or to you & ospho?

I have no doubt you've had success with your method & your paint. I know you've done this more than once and know what you're doing. I trust your results are as described. But rustoleum isn't a paint, it's a brand, and what you've done with whatever specific product you've used is not applicable to other paints, from other manufacturers.

Finally, while some paints may tolerate residual ospho, I've never seen one yet that said it was necessary for proper/enhanced adhesion. You likely have everything to gain, and nothing to lose, by thoroughly removing it while it's still wet. Considering the incredible expense in time/effort/frustration involved if your paint fails, it seems to me to be pretty basic insurance no matter what I'm putting over the top of it. I hate redos on paint. I'm actually redoing our front/rear cap wood right now because I got lazy sanding down the primer. 2 days wasted. Back to square 1.

The SPI thread I linked to above, again, is filled with people who paint for a living - meaning all kinds of different products - all pretty much singing the same tune. Again, it's really worth the read.

[EastCoastCB]

Look man I've used ospho for literally decades. This just seems like a difference of opinion or you just don't understand what I mean by I brush off the oshpo before painting.
Lets just not argue anymore. You have your opinion and I have mine.

[TheHubbardBus]

Originally Posted by EastCoastCB

Look man I've used ospho for literally decades. This just seems like a difference of opinion or you just don't understand what I mean by I brush off the oshpo before painting.
Lets just not argue anymore. You have your opinion and I have mine.

It's not a matter of opinion, it's a matter of fact. And you seem to be unable / unwilling to acknowledge the fact that the way you apply/remove ospho, with the products you use on top of it, doesn't apply to other products. Your comments imply that your way works for other products than what you use, and that's just not true. If you read the thread I linked to, you'd see that SPI saw a 40-60% reduction in adhesion after a dried ospho film was sanded - not just rubbed - but sanded off. They specifically state their paint WILL FAIL if you don't neutralize ospho in their recommended manner (rinsed & rubbed off while wet), which contradicts yours. And I've read other TDS's from other manufacturers of other paints that mirrored their recommendations.

I'm not arguing. I'm just trying to keep people from having their paint fail. The way you use ospho with the paint of your choice will not necessarily work with others. Again - not opinion - fact. And that's the last I'll say.

No hard feelings. Still think you're great & you've helped us immensely. We've taken your advice countless times and profited from it.

[EastCoastCB]

I'm lost as to what you're even on about anymore man. All I did was quote the directions from Ospho that have served me well since 1996 or so. Have a good day.

[ChurchBuz]

Right on! You guys are super helpful! Especially the controversy because it puts the burden on me to take it seriously enough to look into.

Fortunately: the plywood is up which will hold the water.

ATM I am considering using a punch to dimple all the holes downward so that if any water does get in there it can get out. The bus is already 30 years old and the floor is galvanized! Once the rust is neutralized and rust inhibiting paint is down, the odds of enough rust happening to cause a problem is highly unlikely (even if the paint doesn’t stick.

Galvanized will rust if aggravated, but not fast.

I’m going to do my due diligence and then put it underneath and behind me.

If a catastrophic hole rusts through before I die, perhaps it will just spur me to build a Foamie back half. Lol

I love you guys! Thanksgiving y’all for helping and encouraging me

[ChurchBuz]

Correction!!! The plywood is not all up. But is coming up and will not be a problem afterwards