Painting Exterior of Bus

[ChrisLifts]

Is it necessary to sand the entire exterior of the bus prior to putting new paint on? I owned a motorcycle once that was sprayed with matte black truck bed liner. I discovered it was sprayed over an actual paint job when I spilled gasoline on the tank and it literally disintegrated the bed liner revealing a lovely conferedate flag paint job.

My point being, there was a legitimate paint job on the bike and someone literally sprayed bed liner over it. You couldn't tell. The bed liner had been on the motorcycle for years so could I not just do that to the bus provided it doesn't rain gasoline and melt it all off? Obviously if I invested the time into sanding the entire thing down, priming, etc it would be more effective and last longer. But I'll cut corners that aren't structural or quality of life when possible.

[A_Bus_Called_Quest]

You should definitely prep the entire surface for optimal results. Sanding and degreasing w acetone.

If you don't you'll probably end up with a bunch of chips in the paint the first time you get on the highway, or the truck wash..

The only places we have lost paint were the crevices where I couldn't get the sanding pad.

[TheHubbardBus]

If you don't properly prepare your substrate, you compromise paint adhesion. How much you compromise it is the question. The way I see it, you're going to do the work one way or another - either now or down the road via repairs, touch-ups, or even complete do-overs. Even a half-a$$ prep job is a lot of work, and even inexpensive paint is pricey when you're covering something the size of a bus. Maybe you'll get lucky cutting corners. Or maybe what prep you do, and paint you buy, will be a complete waste. Me: I'd rather spend a few extra days knocking out a great prep job, and a few extra dollars on quality paint, and then move on knowing I had put that job behind me for good.

[rossvtaylor]

For those who've painted a whole bus...please share your thoughts or experience. Is there a chemical surface prep option that works?

I've painted medium duty ambulances and had good success with the sanding prep...but those are smaller and have lots of flat surfaces on which air or mechanical sanders work well. And I've painted parts of a bus, also using manual sanding/etching. But I've not painted an entire bus and I cringe at the thought of trying to sand all those ribs and overlapping seams and such.

So, is there a chemical surface prep alternative? I've looked online and only seem to get concrete etching options...not what I need. And the lack of many hits makes me think there's no such viable option. But someone here will know, for sure!

[DeMac]

Originally Posted by ChrisLifts

Is it necessary to sand the entire exterior of the bus prior to putting new paint on? I owned a motorcycle once that was sprayed with matte black truck bed liner. I discovered it was sprayed over an actual paint job when I spilled gasoline on the tank and it literally disintegrated the bed liner revealing a lovely conferedate flag paint job.

My point being, there was a legitimate paint job on the bike and someone literally sprayed bed liner over it. You couldn't tell. The bed liner had been on the motorcycle for years so could I not just do that to the bus provided it doesn't rain gasoline and melt it all off? Obviously if I invested the time into sanding the entire thing down, priming, etc it would be more effective and last longer. But I'll cut corners that aren't structural or quality of life when possible.

It is not necessary to sand the entire exterior of the bus. Nor is it necessary to paint the entire exterior of the bus. You can do as little as you choose to your bus. But what is your need for painting it? Not to make it look good, clearly. Flakes and peals look worse than the factory yellow.

A wide stripe should be enough to not look like a working school bus. Just do the percentage of the bus that you are willing to do well. Leave the parts that you don't need to do, immediately. Skip the window & trim areas.

I passed this one this morning. Clearly not a school bus. Nothing to be re-done, the paint & prep that has been completed & will stay looking good. The owner can add more paint to the untouched areas later.

Start with an easy to reach area, prep, paint, progress, move-on. Do more painting next summer.

[TheHubbardBus]

Originally Posted by rossvtaylor

For those who've painted a whole bus...please share your thoughts or experience. Is there a chemical surface prep option that works?

If you have the original paint still on the bus (either as the only coating or hidden under an aftermarket / DIY paint job), and it still adheres well, I would be hesitant to pursue such options even if they were a viable choice (no idea) The OG paint is industrial quality sprayed to what I assume to be assembly-line 'perfection'. If it's still sticking well (which you can test), I don't think you have anything to gain, and lots to lose, by compromising it, which anything chemical would likely do.

Plus, chemicals are toxic, messy, leave behind a slurry of even more toxic nastiness (which has to go somewhere), and still won't prep the surface adequately for new paint to adhere.

[A_Bus_Called_Quest]

Originally Posted by TheHubbardBus

If you don't properly prepare your substrate, you compromise paint adhesion. How much you compromise it is the question. The way I see it, you're going to do the work one way or another - either now or down the road via repairs, touch-ups, or even complete do-overs. Even a half-a$$ prep job is a lot of work, and even inexpensive paint is pricey when you're covering something the size of a bus. Maybe you'll get lucky cutting corners. Or maybe what prep you do, and paint you buy, will be a complete waste. Me: I'd rather spend a few extra days knocking out a great prep job, and a few extra dollars on quality paint, and then move on knowing I had put that job behind me for good.

Agree with Hubbard here: 2 days sanding / cleaning, 10 hours taping / masking, 1.5 hours painting [emoji854]

I made a pretty detailed write-up of our experience here: https://r.tapatalk.com/shareLink/top...ink_source=app

[TheHubbardBus]

Bear, that job looks awesome! The results of your hard work definitely show!

[rossvtaylor]

Originally Posted by TheHubbardBus

Plus, chemicals are toxic, messy, leave behind a slurry of even more toxic nastiness (which has to go somewhere), and still won't prep the surface adequately for new paint to adhere.

I get the mess part. Sanding creates lots of paint dust, too...which would actually be harder for to contain than a liquid that drips onto plastic...but I do completely understand. The "won't prep the surface adequately" part answers my question - it sounds like there's no shortcut to sanding. I appreciate your experience here...thanks!

[TheHubbardBus]

Originally Posted by rossvtaylor

I get the mess part. Sanding creates lots of paint dust, too...which would actually be harder for to contain than a liquid that drips onto plastic...but I do completely understand. The "won't prep the surface adequately" part answers my question - it sounds like there's no shortcut to sanding. I appreciate your experience here...thanks!

Point taken, and a fair point at that. I was thinking more of the toxicity as it applies to you and your immediate surroundings, particularly your skin.

Happy to help. But to be clear, my experience == 1 bus. Painted other stuff, and unfortunately tried the chemical route once (never, ever again), but just one bus.

[katix]

i've painted my #BarbieDreambus twice in 23 years. the first time i was 23 years old and clueless, and just brushed on exterior house paint with no prep. it was fine for at least a decade, but badly peeling 18 years later (mostly on the side that was facing west in a horrendous hailstorm in 2016,) when i finally went to paint the bus a second time.


the second time i borrowed a power washer, and followed that by scrubbing it with TSP substitute. then painted with a very cheap borrowed electric paint sprayer. still using tinted exterior house paint. it's been 3 years since that paint job, and i'm still quite happy with it. no signs of peeling or other paint failure.



it's certainly not professional, and wouldn't work if i were trying to do this for a living. but i'm not. it's my bus, and it's just fine.



good luck!

[Johnthebusboy]

Painted the roof with "rubber" roof paint. Scoured the roof with nylon pads to get some tooth. And washed it. Did not use any solvents. Worked well but the rubber paint soaks up dirt so I brushed on some house paint. Just enough to test adhesion and durability. So far so good.

[dozr62]

Sanding is not possible for me so I bought a small sandblasting kit and compressor had a small truckload of sand delivered and I use a window screen to filter the sand before putting it in the hopper easy peasy. Northern tool. HarborFreight it doesn't have to be expensive.

[ewo1]

Originally Posted by dozr62

Sanding is not possible for me so I bought a small sandblasting kit and compressor had a small truckload of sand delivered and I use a window screen to filter the sand before putting it in the hopper easy peasy. Northern tool. HarborFreight it doesn't have to be expensive.

PLEASE!!!! If you are blasting with dry “sand” wear an approved respirator.

I have been sandblasting for about 7 years now and I can tell you -fact, dry sand when it impacts breaks up and causes an almost invisible powder cloud that contains “free silica” which if breathed in will stay, remain in your lungs FOR LIFE! Your lungs WILL NOT expel the silica dust you breathe.

I do not blast dry without wearing a nova blast hood, they are costly, $450+.
Paper dusk masks are not good, don’t be fooled and please don’t play games with your lungs!

I also blast wet with a professional unit made by “farrow systems”.

As an alternative I would highly suggest either changing your media to crushed glass which has almost zero free silica or if you have a lot of sand already then use a “wet sandblasting tip” that you can attach to a pressure washer.
If you go with the pressure washer route, you will have to Ospho the entire bus but the good thing is that you can spray on the Ospho with a cheap harbor freight sprayer. You only want to apply it in a very, very fine mist.

I do big projects this way, many times with good results.
On the big projects when I spray it on, I follow it up by simply wiping the excess Ospho with a clean rag. No need to use multiple rags, one will do just fine on the entire bus. The goal is to leave a very, very fine film of Ospho.

Once the Oshpo dries you can then paint.

The Ospho prevents flash rust from immediately forming on the clean naked steel.


Here is a YouTube video of me sandblasting a boat hull to remove the bottom paint. You will see how by adding water it completely reduces/eliminates any free silica from going into the air making it safe not only for the blaster but also those people in the immediate work area too!

https://youtu.be/a4EMmjZkGcQ

Also, if you are using playground sand watch out for the big pieces, they will clog up your blaster or pop a nice size dent in thin metal.
It is really a good idea you are screening it so that way you get uniformity in your blast material.

If you decide to go the pressure washer route, start from far away, not close up and find that sweet spot that gives you a smooth clean surface versus a highly etched profile. If you have the tip to close you risk putting on too heavy of a profile on the metal which will result in either having to sand it down or using high build primer which will more than likely require more sanding.

I do boat bottoms, removing anti fouling paint from a gel coat surface. Technique is the key here so like I said, start from 4-5 feet away and come in closer as you get comfortable in finding that sweet spot for a smooth surface.

Also when blasting wet, you don’t have to worry about warping the metal as there is no heat being produced because the water will not only keep the metal cool but will also dramatically help in getting a smooth profile surface that will be ready for paint with very minimal sanding.

Good luck !

[aridgedell]

Originally Posted by ChrisLifts

Is it necessary to sand the entire exterior of the bus prior to putting new paint on? I owned a motorcycle once that was sprayed with matte black truck bed liner. I discovered it was sprayed over an actual paint job when I spilled gasoline on the tank and it literally disintegrated the bed liner revealing a lovely conferedate flag paint job.

My point being, there was a legitimate paint job on the bike and someone literally sprayed bed liner over it. You couldn't tell. The bed liner had been on the motorcycle for years so could I not just do that to the bus provided it doesn't rain gasoline and melt it all off? Obviously if I invested the time into sanding the entire thing down, priming, etc it would be more effective and last longer. But I'll cut corners that aren't structural or quality of life when possible.

We painted our bus two years ago with rustoleum from homedepot and an airless sprayer. I just pressure washed and only sanded a couple small spots that were peeling. I have had to do a little touchup here and there but way better than sanding the whole darn thing! I just painted over the replective tape with no problems. used 4 gallons. no regrets.

[Tin Roadtube Vagrant]

Decide which you want and go with it. Either a good job or mediocre. If you do a good job take a week off of work and do it inside if possible. If you do a shade-tree job make it cheap, fast and easy. Don't try for an in-between.

I just did mine outside in the elements at a specific time of the year. It was hell, but it looks fabulous. Sanded and prepped the whole unit. Lot of work. Keep the goal in your mind to inspire the work your undertaking. Each section I did I masked the entire finished portion of the bus to protect it from over spray. I did the roof in sections, per tin rivet line, sometimes 2 sections at a time. Use the lines of the tin as your masking It sounds counterintuitive, but start from the bottom of bus then up if your outside in the elements. remove the hood and finish it remotely then tuck it away till completion. Use Rusto, but treat it like high dollar paint in the way you apply it, keeping your wet line true. Get a big gun and set the regulator to pressure kick in point of compressor. Move a lot of paint fast, be ready to sweep very very fast to keep up with volume and to keep the paint wet enough to reabsorb overspray. Good Luck!

[TheHubbardBus]

Originally Posted by Tin Roadtube Vagrant

Decide which you want and go with it. Either a good job or mediocre. If you do a good job take a week off of work and do it inside if possible. If you do a shade-tree job make it cheap, fast and easy. Don't try for an in-between.

This is excellent advice IMO. And it applies to prep as well.

[rydawg3000]

Not feasible for everyone and probably not the most ecologically friendly, but my wife painted the entire exterior of our bus by hand with spray paint. We used Tractor Paint in Ford Grey and it turned out just great. For the bumpers we used the black Rustoleum Bumper Spray (literally has a picture of a school bus bumper on the cans logo I believe)
The biggest pain was spraying the trim between the windows but with patience and much tedious prep work it came out great.

Feel free to rip us on this, but we did little to zero prep work as far as deep cleaning or sanding. We cleaned and pressure washed it realllly well, sanded down any spots that previously had reflective tape or decals, then rubbed down clean with acetone the day of spraying.

We have been living in it full-time in Pensacola located in NW Florida for 2 years now and don’t have many issues with paint other than spots on the hood that I have scratched up with my shoes climbing on or off the roof!

[ChrisLifts]

Originally Posted by rydawg3000

Not feasible for everyone and probably not the most ecologically friendly, but my wife painted the entire exterior of our bus by hand with spray paint. We used Tractor Paint in Ford Grey and it turned out just great. For the bumpers we used the black Rustoleum Bumper Spray (literally has a picture of a school bus bumper on the cans logo I believe)
The biggest pain was spraying the trim between the windows but with patience and much tedious prep work it came out great.

Feel free to rip us on this, but we did little to zero prep work as far as deep cleaning or sanding. We cleaned and pressure washed it realllly well, sanded down any spots that previously had reflective tape or decals, then rubbed down clean with acetone the day of spraying.

We have been living in it full-time in Pensacola located in NW Florida for 2 years now and don’t have many issues with paint other than spots on the hood that I have scratched up with my shoes climbing on or off the roof!

This right here is basically what I was going to go for. It's going to be a matte color so I'm not going for a professional glistening finish. Just sand spots where it peeled off from removing school letters and decals, give it a nice bath, and go to town with cans of spray on bedliner or a similar type of paint to the one you used. If you've gone 2 years with no issues, that's good enough for me.

[Mr_Geenie]

I had some rust to repair, and a LOT of reflective material of some sort that was adhered with body puddy and glue. It took hours with a grinder with a flapper disc to get it all off, then I had lines running down the bus that were visibly of a different height than the painted surface so I had to build back up with 4 and in some places 5 coats of sandable filler primer. Since I already had that much effort put in, I sanded the entire bus with 320 grit and did 2 coats of primer before sanding again with 320 to make it nice and smooth. The roof got a TSP bath amd scubbing and then 2 coats of Henry's Tropicool 887.
It's waiting in line for a spot in the spray booth for a coat of PPG sealer to make sure none of the yellow bleeds through, and then she will be painted with 2 coats of PPG automotive paint Toyota's "Voodoo Blue" with GM "Olympic White" on the bumpers and the lowest set of wall ridges (i dont know what else to call those rows of "fins" that run the length of the bus)