What's the very best way to prep, paint, & seal the floor?

TheHubbardBus · 07-02-2019, 10:51 AM

Got our plywood out exposing the interior of the metal floor, and there's inevitably a good measure of rust. Even in the 'bad' spots, however, there's plenty of meat left. Definitely no structural issues, but some scale in places, and significant surface rust.

I had originally considered something like POR15/KBS, but after spending some time on the paint forums, it seems many professional restorers view these products as potentially problematic.

Considering the nature of the beast (after the conversion, we'll never see that floor again), we want to make sure to do the job as right as we can. To me, that seems to mean taking the rust down to the bare metal. And that's I intend to do.

So - once I do - what is the best paint/coating to use to use in this application? Epoxy, Eurethane, something else?

I have nearly everything necessary to spray myself, and can/will purchase anything we don't have.

CMORGANSKOOL · 07-02-2019, 11:19 AM

Put ospho in a 2 gallon bug sprayer and spray down all the rusty surfaces. No rust removal necessary, then paint. It's also great for frame, undercarriage rust. No special prep necessary. I put several sprays down. It converts even the crusty scale to usable surface.

https://www.amazon.com/SKYBRYTE-COMP...gateway&sr=8-4

TheHubbardBus · 07-02-2019, 11:35 AM

Quote:

Originally Posted by CMORGANSKOOL

Put ospho in a 2 gallon bug sprayer and spray down all the rusty surfaces. No rust removal necessary, then paint. It's also great for frame, undercarriage rust. No special prep necessary. I put several sprays down. It converts even the crusty scale to usable surface.

Thanks, CMorgan. I had planned on using ospho to get in the pits after extensive wire-brushing, but I'm a bit nervous about just using chemical means alone. Wouldn't properly prepped bare metal promote better long-term adhesion than the resultant oxide? Couldn't rust in the deeper spots be trapped between the converted layer and the underlying metal?

Also, at least one epoxy manufacturer (SPI) specifically states that ospho must be entirely and effecitely neutralized/removed before painting.

EastCoastCB · 07-02-2019, 04:08 PM

Quote:

Originally Posted by TheHubbardBus

Got our plywood out exposing the interior of the metal floor, and there's inevitably a good measure of rust. Even in the 'bad' spots, however, there's plenty of meat left. Definitely no structural issues, but some scale in places, and significant surface rust.

I had originally considered something like POR15/KBS, but after spending some time on the paint forums, it seems many professional restorers view these products as potentially problematic.

Considering the nature of the beast (after the conversion, we'll never see that floor again), we want to make sure to do the job as right as we can. To me, that seems to mean taking the rust down to the bare metal. And that's I intend to do.

So - once I do - what is the best paint/coating to use to use in this application? Epoxy, Eurethane, something else?

I have nearly everything necessary to spray myself, and can/will purchase anything we don't have.

Me and my friend Shaun just pulled up his floors. Next up is to wire brush the scale and then convert the rust with Ospho or a similar product.
I'd just splash some rust converted on the metal and then roll some rustoleum on it. That's our plan. May add a bit of hardener to the rusto.

EastCoastCB · 07-02-2019, 04:09 PM

Quote:

Originally Posted by TheHubbardBus

Thanks, CMorgan. I had planned on using ospho to get in the pits after extensive wire-brushing, but I'm a bit nervous about just using chemical means alone. Wouldn't properly prepped bare metal promote better long-term adhesion than the resultant oxide? Couldn't rust in the deeper spots be trapped between the converted layer and the underlying metal?

Also, at least one epoxy manufacturer (SPI) specifically states that ospho must be entirely and effecitely neutralized/removed before painting.

The resultant oxide is a great surface for the paint to stick to. Much more so than bare metal, believe it or not.
If its super thick you can rinse it after a day or so. I just quickly wire wheel it after ospho and then paint it.

TheHubbardBus · 07-03-2019, 08:33 AM

Good to know.

We're just beginning the monsoon season here... hottest temps combined with highest (and most unpredictable) rainfall / humidity levels. I figured i"d probably hold off spraying the floor until after the summer, to avoid these extremes.

Would I better off to just leave it as is and then surface it right before painting? Or prep it now and put down ospho as a rust inhibitor (and does it act as a rust inhibitor) for the 3 months or so before i paint?

CMORGANSKOOL · 07-03-2019, 09:09 AM

Quote:

Originally Posted by TheHubbardBus

Thanks, CMorgan. I had planned on using ospho to get in the pits after extensive wire-brushing, but I'm a bit nervous about just using chemical means alone. Wouldn't properly prepped bare metal promote better long-term adhesion than the resultant oxide? Couldn't rust in the deeper spots be trapped between the converted layer and the underlying metal?

Also, at least one epoxy manufacturer (SPI) specifically states that ospho must be entirely and effecitely neutralized/removed before painting.

I've seen people on here do both grind and wire brush, and just spray alone. I'm recovering the floor so I don't mind the scale. The sprayer does a great job soaking through all the layers and converting them into hard nonreactive surfaces. I would say wire brush and treat surfaces that you plan on looking at only. The rest based on my experience paints over fine.

CMORGANSKOOL · 07-03-2019, 09:41 AM

Quote:

Originally Posted by TheHubbardBus

Good to know.

We're just beginning the monsoon season here... hottest temps combined with highest (and most unpredictable) rainfall / humidity levels. I figured i"d probably hold off spraying the floor until after the summer, to avoid these extremes.

Would I better off to just leave it as is and then surface it right before painting? Or prep it now and put down ospho as a rust inhibitor (and does it act as a rust inhibitor) for the 3 months or so before i paint?

Inside I treated months ago and haven't painted yet. I also found and sealed several leaks over that time. Which you'll find during monsoon season. I have used about 2 gallons of ospho so far. Based off my experience it converts and inhibits rust even when not painted. I retreated a couple spots after they got wet from leaks. I'd advise you to treat now and stop the rust advancing then decide whether it needs re-treating before painting. Prep time is basically just waiting for it to dry before painting so you can really play it by ear.

TheHubbardBus · 07-03-2019, 10:55 AM

Good stuff! Very much appreciate the input!

I'll go ahead and knock the floor down now (still going to manually get down to metal as best I can, because my OCD won't have it any other way), treat it with ospho as you suggest, and then finish up with paint once the summer's over & temp/humidity levels are more favorable.

In the meantime, I can research paints a bit more, and there's still a ton of work that needs to be done that won't yet require flooring.

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