Spray vs Rolling Paint on Roof. How, why, what, where.

TheHubbardBus · 09-07-2019, 05:25 PM

I plan on spraying as much of the bus myself as possible. I don't anticipate any problems with the interior, or the exterior, with one exception... the roof.

It's high. Our bus is close to our house & others. I'd have to spray down at it. I'm a big guy who's afraid of denting the roof walking on it. Blah blah blah. Long story short, I'm not nearly as confident with my ability to spray the roof as I am everything else.

I don't want to half-ass anything. Especially not the roof. So I have two questions, the second dependent on the answer to the first:

1) Would there be any measurable difference in performance, longevity, or sealing ability between rolling and spraying (assuming elastomeric paint).

2) If the answer is yes (in favor of spraying), what would suggest to help overcome some of my concerns above?

Thanks!

o1marc · 09-07-2019, 05:42 PM

I doubt you'll dent the roof walking on it, but then I have no idea what you weigh. I would think trying to get a thick layer spraying may develope runs you won't get rolling.
I have another question, how is everyone addressing the edge at the transfer between the elastomeric and the painted sides. I think I want to spray body color down along the edge and then tape off for roof paint. That way I don't have to fight taping a thick sharp edge to paint the sides. That or paint the sides first, which won't happen in my case.

TheHubbardBus · 09-07-2019, 11:59 PM

I'll answer my own question... I should have done some research before posting.
It looks like spray elastomeric paint aint happening with any equipment I have.
Back to the drawing board.

Native · 09-08-2019, 03:50 AM

Rolling worked great for us. It adds a little texture which scatters the sunlight a bit. This is a good thing for me.

As for walking on the roof ... I did it by waling as close to the rails and at the rivets where the hat channel is. If I stepped between, then the roof would detent a bit. Nothing that looked like it was lasting though.

I rolled right down to the drip rails and used a brush to cut in from the rail. I ended up developing a technique with the brush to get a similar texture to that which the roller produced.

On a test piece, I rolled some elastomeric paint and let it dry normally. I then applied primer to part . I applied implement paint (the stuff I will be using on the sides) to both primered elastommeric paint and non-primered elastomeric paint. The primer cracked. The primer and paint looked okay, but had some crazing The paint directly applied to the elastomeric paint covered wall with no effects other than the luster of the paint is not the same as primed annd sanded bare metal.

DoxieLuvr2015 · 09-08-2019, 04:47 AM

Quote:

Originally Posted by TheHubbardBus

I plan on spraying as much of the bus myself as possible. I don't anticipate any problems with the interior, or the exterior, with one exception... the roof.

It's high. Our bus is close to our house & others. I'd have to spray down at it. I'm a big guy who's afraid of denting the roof walking on it. Blah blah blah. Long story short, I'm not nearly as confident with my ability to spray the roof as I am everything else.

I don't want to half-ass anything. Especially not the roof. So I have two questions, the second dependent on the answer to the first:

1) Would there be any measurable difference in performance, longevity, or sealing ability between rolling and spraying (assuming elastomeric paint).

2) If the answer is yes (in favor of spraying), what would suggest to help overcome some of my concerns above?

Thanks!

Question on the OP. Why do some choose to use elastomaric paint on their conversions? I was looking into epoxy based paints...(we use lot of these in the navy)

Second thought. If the orgininal paint is in good shape and so is the integrity of the sheet metal of the roof would a paint like EP be recommended?

musigenesis · 09-08-2019, 08:25 AM

Quote:

Originally Posted by DoxieLuvr2015

Question on the OP. Why do some choose to use elastomaric paint on their conversions? I was looking into epoxy based paints...(we use lot of these in the navy)

Second thought. If the orgininal paint is in good shape and so is the integrity of the sheet metal of the roof would a paint like EP be recommended?

People seem to mainly do Henry's Tropicool on the roof, and mainly because of its reflective properties - the elastomeric aspect is a side benefit that also helps seal up the roof. By most accounts, Tropicool is better than simple white paint on the roof.

TheHubbardBus · 09-08-2019, 10:32 AM

Quote:

Originally Posted by DoxieLuvr2015

Question on the OP. Why do some choose to use elastomaric paint on their conversions? I was looking into epoxy based paints...(we use lot of these in the navy)

Second thought. If the orgininal paint is in good shape and so is the integrity of the sheet metal of the roof would a paint like EP be recommended?

Honestly, I don't want to. I'd rather spray the whole thing with automotive paint, including the roof (either epoxy or urethane). Much rather. My main concern is to prevent leaks from coming in around these 15-year-old rivets or seams, either now or in the future. I don't see any now (other than one rivet that's missing and will therefore need to be replaced), but I'm kind of wanting to future-proof things.

I plan on prepping well and resealing all seams as best I can before doing anything. I don't know if there's anything I can do around the rivets that would achieve the same results.

So yeah... if anyone can tell me how I can assure a good seal with auto paint, I'm all ears. Maybe I'm over other thinking things. Maybe it is a good seal?

TheHubbardBus · 09-08-2019, 10:35 AM

Quote:

Originally Posted by Native

Rolling worked great for us. It adds a little texture which scatters the sunlight a bit. This is a good thing for me...

Thanks for all the info, Native. Much appreciated!

PNW_Steve · 09-08-2019, 10:45 AM

Quote:

Originally Posted by TheHubbardBus

Honestly, I don't want to. I'd rather spray the whole thing with automotive paint, including the roof (either epoxy or urethane). Much rather. My main concern is to prevent leaks from coming in around these 15-year-old rivets or seams, either now or in the future. I don't see any now (other than one rivet that's missing and will therefore need to be replaced), but I'm kind of wanting to future-proof things.

I plan on prepping well and resealing all seams as best I can before doing anything. I don't know if there's anything I can do around the rivets that would achieve the same results.

So yeah... if anyone can tell me how I can assure a good seal with auto paint, I'm all ears. Maybe I'm over other thinking things. Maybe it is a good seal?

I have seen some folks here apply a body seam sealer tape over each seam on the roof before painting. That would address your leak concern and allow you to use the paint you want.

I am not a fan of tropicool. The applications that I have seen had a bit of texture and held dirt making it look a bit dingy.

Lots of folks here have used Tropicool or similar products and are happy with the outcome.

o1marc · 09-08-2019, 12:48 PM

Ya'll have me second guessing the Henry's now. I thought with it's self leveling feature it would lay smooth. Now everyone is saying it leaves a texture. The last thing I want on my roof is a texture for dirt to accumulate.

bus-bro · 09-08-2019, 02:19 PM

I rolled on Tropi-cool, there is some texture but it looks good nonetheless. Even if I had an airless that could pump it I would still roll it. That paint turns into rubber pretty quickly. Much easier to throw a roller away than clean a pump and fifty + feet of hose of that stuff.

EastCoastCB · 09-08-2019, 03:42 PM

Keep your weight on the ribs and you won't damage anything or make any dents.
I'd roll it. Its harder to spray up there at those angles.

TheHubbardBus · 09-08-2019, 06:57 PM

Quote:

Originally Posted by PNW_Steve

I have seen some folks here apply a body seam sealer tape over each seam on the roof before painting. That would address your leak concern and allow you to use the paint you want.

Thanks Steve.

Would the tape conform to the surface of rivets? Or would it be like a little pocket on top? I'm not sure if my question makes sense, but hopefully it does.

musigenesis · 09-08-2019, 07:48 PM

Quote:

Originally Posted by TheHubbardBus

Thanks Steve.

Would the tape conform to the surface of rivets? Or would it be like a little pocket on top? I'm not sure if my question makes sense, but hopefully it does.

I used Dynatron-550 to create a 1" wide strip over each seam between roof panels, so a half inch on each side of the seam. The rivets are far enough from the seam that they don't come into play.

PNW_Steve · 09-08-2019, 08:13 PM

Quote:

Originally Posted by TheHubbardBus

Thanks Steve.

Would the tape conform to the surface of rivets? Or would it be like a little pocket on top? I'm not sure if my question makes sense, but hopefully it does.

I understand your question. I am not sure of the answer. I have observed others do it but have not tried it myself. Knock on wood.........

Perhaps one of the folks who have first hand experience will chime in.

Native · 09-08-2019, 11:47 PM

Quote:

Originally Posted by TheHubbardBus

Thanks Steve.

Would the tape conform to the surface of rivets? Or would it be like a little pocket on top? I'm not sure if my question makes sense, but hopefully it does.

We used 6" and 4" Eternabond on all seams and rivets. First we had to remove all of the silicone SOMEONE had put all over the rivets and some seams. The EternaBond does not stick to silicone. The EternaBond will *mostly* adhere tightly to the rivets. You do have to go slow around the rivets and press it in well arounnd them. A few of my first rivets did not get the proper attention as I had not yet learned the technique. They are sealed up, but do show a little pucker.

If I can find pictures of the rivets, I'll post them.

TheHubbardBus · 09-09-2019, 10:01 AM

Thanks everyone. Really appreciate all the advice. I'm leaning further & further away from the elastomeric now. New plan is to get everything watertight w/o relying on a 'paint', and then choose the coating based on other factors.

The only other advantage I'm seeing to elastomeric is cooling, and from what I can tell (correct me if I'm wrong) that appears to be a function of color and thickness. I doubt I can put down the same thickness as elastomeric with auto paint, but I think with 2-3 coats of something high-build (in white, of course) I wouldn't be sacrificing a whole lot?

EastCoastCB · 09-09-2019, 10:10 AM

Quote:

Originally Posted by TheHubbardBus

Thanks everyone. Really appreciate all the advice. I'm leaning further & further away from the elastomeric now. New plan is to get everything watertight w/o relying on a 'paint', and then choose the coating based on other factors.

The only other advantage I'm seeing to elastomeric is cooling, and from what I can tell (correct me if I'm wrong) that appears to be a function of color and thickness. I doubt I can put down the same thickness as elastomeric with auto paint, but I think with 2-3 coats of something high-build (in white, of course) I wouldn't be sacrificing a whole lot?

I like the way you're thinkin.