School bus paint job

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Xalexjpx

I am converting a school bus into a rv. Getting it prepped for paint. I have stripped down parts to bare metal/galvanized, and sanded other parts with 120 grit. What is my best option for primer? Epoxy the whole thing? Use a hybrid combo like super build? Total noob here. I know the best is to strip to bare metal but that's not going to happen. Please help
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If you want it to last, spray two coats of epoxy on the whole sanded area.
Then use a 2k urethane primer for blocking.
 
If some of that is raw aluminum, your best first step with it is having it clean as possible & coated as soon as possible after final clean. Aluminum starts oxidizing immediately. Don't even think about hitting it with 2k primer, acid etch or any of these other aluminum treatments. go straight for epoxy. Epoxy only for galvanized stuff. For a project like yours , you could even spot prime the raw areas with one coat as you continue sanding. If you give a few days dry time, you could do epoxy only for all priming & blocking for best durability, as epoxy has strength in thickness when cured.

Epoxy has a long pot life , so you can mix extra & keep in sealed container for a few days, but not in gun. This looks like you may be spraying this monster outdoors, so be sure to re read up an minimum temps and have a infared temp gauge.
What color are you wanting to do? Not many single stage colors here, but SPI single stage would be great here.
 
If some of that is raw aluminum, your best first step with it is having it clean as possible & coated as soon as possible after final clean. Aluminum starts oxidizing immediately. Don't even think about hitting it with 2k primer, acid etch or any of these other aluminum treatments. go straight for epoxy. Epoxy only for galvanized stuff. For a project like yours , you could even spot prime the raw areas with one coat as you continue sanding. If you give a few days dry time, you could do epoxy only for all priming & blocking for best durability, as epoxy has strength in thickness when cured.

Epoxy has a long pot life , so you can mix extra & keep in sealed container for a few days, but not in gun. This looks like you may be spraying this monster outdoors, so be sure to re read up an minimum temps and have a infared temp gauge.
What color are you wanting to do? Not many single stage colors here, but SPI single stage would be great here.

Thanks for the response. There is no aluminum. Mostly galvinized except for the steel sheets behind the windows. Thats a great tip for spot coating. Those steel sheets rust so fast I was worried about how to strip and paint in 1 day.
I am painting outside, we are near Havasu so the temps will be in the low to mid 80s next week.
My original plan was to raptor line the whole bus but a friend just talked me out of it. I have a bunch of tonor I had bought (anvil blue) that I'm hoping the local paint shop can turn into a single stage paint for me.
 
If you want it to last, spray two coats of epoxy on the whole sanded area.
Then use a 2k urethane primer for blocking.
Will do on the epoxy. Part of the bus was repainted at some point. I'm trying to sand down to original paint but hard to tell. Any problems with the epoxy going over old paint? What about a polyester to smooth things a bit? I cant spend the time sanding out every imperfection on this monster.
 
Any primer you spray over the epoxy will only give you something to sand out imperfections with. Polyester just gives more thickness to sand out deeper imperfections, it's not self leveling. It builds evenly over the highs and the lows, if that makes sense. If you're not going to worry about imperfections, just epoxy and paint, otherwise you will just be wasting money on polyester or 2K
 
Any primer you spray over the epoxy will only give you something to sand out imperfections with. Polyester just gives more thickness to sand out deeper imperfections, it's not self leveling. It builds evenly over the highs and the lows, if that makes sense. If you're not going to worry about imperfections, just epoxy and paint, otherwise you will just be wasting money on polyester or 2K
Gotcha, I was planning on sanding down the poly, just not to perfection. Makes sense about not being self leveling, in my head I thought it would just smooth it all out. Maybe I'll do a couple coats of epoxy and see how she looks then decide. Thanks
 
As far as rusting & finishing in 1 day, if you have 2 consecutive days you could stop sanding a little less than prefect to go further & a quick rehit with sanding the next day before spraying as an option. Light flash rust removes easily.
Though you have to pace your time to not spend forever, you want at the least to do one sanding over primer for it to all blend out. could still spot prime more on all the worse areas. Hopefully you have a 6" or larger sander to speed up the task. Make sure your final primer coat doesn't reveal random sanded areas underneath.
Epoxy will build & sand as out as good as 2k primer, it just takes longer to dry enough & more coats to build. A poly primer surfacer , such as evercoat g-2 would build & dry for sanding faster, but I'd use only where needed and it HAS to be recoated with 2k or epoxy to seal it. You always sand off what you don't need with a product like it. Need a 2.2 or larger tip gun for it.
No one way to do this, but absolutely start with epoxy and finish with a thinned coat of epoxy for sealer for increased durability/ rock chip protection. I would not skip this step in this application.
 
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That's a whole lotta bus there! If I was doing it, (thank the good lord I'm not:)) I would work it in sections. Make it a whole lot more manageable. Sand a section, work what's necessary, and spot mask, then epoxy. Correct any big flaws and leave the small stuff. To do that whole bus you are going to use a lot of product. Budget for that. I'd also plan on when you paint it to do it in a single stage. One man trying to paint that beast in BC/CC would be rough.
 
That's a whole lotta bus there! If I was doing it, (thank the good lord I'm not:)) I would work it in sections. Make it a whole lot more manageable. Sand a section, work what's necessary, and spot mask, then epoxy. Correct any big flaws and leave the small stuff. To do that whole bus you are going to use a lot of product. Budget for that. I'd also plan on when you paint it to do it in a single stage. One man trying to paint that beast in BC/CC would be rough.

This is probably the way to go. It does feel unmanageable and insurmountable at this point. So if I do it in sections I'll probably go over the 7 day window on the epoxy to spray another coat, poly primer or paint. Does the epoxy just need a good scuffing or is it a full re sand? Definitely going with a single stage paint.
 
This is just a guess and probably on the low side, assuming you are doing everything but the top, I would say at least 5 gallons of epoxy and 5 gallons of activator. That would be 10 gallons of ready to spray product. Probably not enough but by the time you sprayed that you would have a pretty good idea of how much more would be needed. My gut tells me probably 8 gallons of epoxy and 8 gallons of activator total. That is assuming you spray two coats of epoxy on it all.
Have you decided on a a final color? From an affordability standpoint Single stage white would be my choice. It'll help hide any flaws you might have and is the most affordable color pricewise. If you sealed the bus in white epoxy (or used white epoxy throughout and spray over your sanded epoxy) it would help cut down the amount of SS needed. Count on somewhere between 4-8 gallons of color, 2 gallons of urethane reducer and 1-2 gallons of activator. This is all just a guess from looking at your pic. I may be off somewhat. Once you spray epoxy over the whole bus then you should have an idea of how much it will take. You could also run a stripe or two to help break up the white if you wanted to.
Some of the other guys here may have their own idea of how much product it would take. Like I said I may be off somewhat.
 
Can anyone recommend a decent budget pressure pot/gun setup. Should I go with a 2 quart or 2.5 gallon?
 
Can't think of a brand right now that would be budget. Pressure pot systems are more common to the woodworking/ cabinet industry, though not a bad idea for a bus. .Just would need to have a gun with more than 1 size tip or more than 1 gun that would be suitable for auto paint. Kremlin is a good industrial brand that probably has a pot system also. Cleaning out hose is a pain in the butt, so I'd go for the larger.
Pressure pot systems should do pretty damn good for primers with less overspray as they are great for pushing thicker liquids efficiently.
 
High quality setup is not going to be cheap. 2 quart will be your only affordable option as the big 2.5 gallon tanks are much higher. Not nearly as many pressure systems/guns available as there was 25 years ago. Here is one that is fairly decent quality:

https://www.tooltopia.com/devilbiss-flg675.aspx

Here is one by Astro Pneumatic which is more affordable, but lower quality I would assume. Plus for it is that it is a 2 1/4 gallon tank.
https://www.tooltopia.com/astro-pneumatic-pt2-4gh.aspx

Here is one on Amazon. I can't speak to the quality but it is cheap
https://www.amazon.com/TCP-Global-Pressure-Paint-Nozzle/dp/B001Z0RAW0

Googling I did find this which if you paired it with an appropriate hose and a good gun should work.

https://www.harborfreight.com/2-1-2-half-gallon-pressure-paint-tank-66839.html

In the past I have sprayed storage containers for a guy who customized them for BWX Technologies. Myself and another guy would spray them inside and out and we used just regular gravity feed guns. Pain in the butt, but we could do it. You may want to consider painting it in sections like I advised priming it in sections above. Do it that way it's manageable and more easily accomplished with conventional equipment.

Like I said earlier better you than me.:)
 
I have been using a pressure pot system in my wood shop for years. I actually have 3 of them- a 1 gallon, 2.5 gallon, and a 5 gallon system, all bought used on Craigslist, all Devillbiss. I set them up with different guns, depending upon what I'm spraying. I bought a roll of the paint hose and a roll of air hose, so I just make new hoses as needed.

When I painted the 51 Ford truck, I bought a 2 qt. Devillbiss pot with a Techna ProLite gun, lightly used, on eBay. Still paid over $500.00 for it all. I used it for primer and single stage SPI, both sprayed no problem.

If I were spraying something as large as that bus, I would set up the ProLite on my 2.5 or 5 gallon pot, and make up a set of hoses at 25' or so.

Yes, it is a lot of hose to clean, but I backflush when done priming or painting, fill the paint hose with solvent, and let it soak. The backflushed paint can be finished off with a cup gun or gravity gun.

You can find what you need used, but it won't be cheap. For a job this size, you really do need that set up, otherwise your arm will fall off long before you are done spraying.
 
I am with Chris on painting it in sections. Going with a solid color you could take each section from start to finish and still have the finished product looking great.
Some guys are going with bedliner on the front to help fight off stone chips. If you go that route you will want to make sure the bedliner is tinted to your finish color so the stone chips that do come won't stick out like a sore thumb.
 
I cant spend the $500+ on those setups and some of the reviews on the cheaper ones make me hesitant. What's the most amount of paint you guys would mix at a time? The pot life says 1-4 hours for the single stage. The recoat time says 10-15 mins, is that the minimum? Can I recoat in an hour after I finish the first coat? If I were to do it in sections would i paint 1 side, wait until it drys, scuff the edge and blend? I am in way over my head, my dad will be helping and has sprayed a few cars but no expert.
 
this is how id paint it:
first that trim separating the dark gray and yellow- id prolly paint that a different color so from there up spray vertical front to back. then the lower same fashion. get however many coats necessary on that one side before moving to the other side,front, or back.


i did a 24' enclosed trailer once with a copper tekna with a 1 quart cup .it was not enjoyable at all. youll spend more time filling the cup and mixing paint than spraying i strongly encourage you to find a pressure pot. look on CL and call/stop in to pawn shops. it will make this job a LOT easier for you....errr....easier for your dad. :)
 
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