air conditioner

[CCurran88]

I pulled up the floor, and there is some pretty significant scale rust under there, but the few small holes were pin-sized to just over a half-dollar size here and there. Nothing around the wheel wells. Still a bit disheartening, since we paid a bit more for a clean "Texas" bus that only had a tiny speck of rust under the license plate when we looked her over. I think that the school district from where we purchased it just pressure-washed the floors periodically to keep the dirt and kid-gunk down. Washing from front to back, letting it all drain out the back door. They assumed, incorrectly, that the rubber mats would keep the wet off the steel. When we pulled one of the plywood sheets up, it was still damp underneath, and I bought the bus around the 7th of April. So, boo, hiss, and oh, well. I spent today figuring out what method would work best to get the rust off. I started with the cupped wire brush and angle grinder, but that really only flaked off some of the layers, and polished the rest. If you whacked it with a hammer, the shiny pretty stuff still flaked off. The next step was to take the grinder disk, one a little thicker than the one I used to cut off the bolts, and sort of scraped off the flaky layers to get down to the pitted metal. Long work. I managed (doing this almost all day) to do about 8 square feet. Only 116 more to go I reckon. My question to the forum is this: How far down should I go? Just past the flaky layers? If I were to put rust converter on top of flaky layers, wouldn't I just have converted flakes? We are doing this on a friends new driveway, so I hesitate to use any converters that have to be rinsed off.

[milkmania]

...but, how's the air conditioner?

[Robin97396]

By time you get done grinding on that floor you're going to want to wash the rust off yourself and the bus. Try to get any scale or flaky metal off. Patch whatever holes as best you can and remember to seal the floor from underneath when you're done.

You sound like you've got it well in hand.

[CCurran88]

Has anyone tried using the gel rust remover with any success? I would like a magical rust removing solution. My arms hurt. I'll keep up with the grinder, but I would truly love a magic wand.

[EastCoastCB]

Originally Posted by CCurran88

Has anyone tried using the gel rust remover with any success? I would like a magical rust removing solution. My arms hurt. I'll keep up with the grinder, but I would truly love a magic wand.

Try ospho.

[Elfie]

For any rust converter to work half decent all the rust scale has to be removed.
Hitting with a pointy hammer, like a welding hammer, will mostly kick it loose. Sometimes several layers of scale are on top. It is very demotivating work since with each layer coming of the remaining steel gets thinner and thinner till the hole appears. Personally I probably would make holes in the floor to allow future to be wet plywood to dry out. Several busses do not have a steel floor and I think that it was mostly intended as a fire barrier for the kids inside.

Rust once started is almost impossible to stop. Rust converters can do a decent job but I doubt that in non breathing somewhat damp environment it will hold not longer then 6 month to a year.

Good luck j

[family wagon]

How about a pneumatic needle scaler to free the loose rust? Maybe anything that holds on well enough not to be dislodged by the scaler is holding well enough to be left alone.