Spray can vs. spray gun

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thill

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Warning- this is a bit long.

For years, I have used rattle can paints with good success. Here is video I made years ago, cleaning up a Johnson 200 Venom:

Part 1:
Part 2:

As you can see, the engine turned out great. It went from terrible to smooth and glossy in minutes. I love OMC factory paint. But about 15 years ago, I bought an HVLP gun to shoot some gelcoat, and it kicked off in the gun and locked up. So annoying! I rolled the rest with a sponge roller, and it turned out great. Who needs a stupid gun?

Recently, I've been welding up a Spectrum aluminum boat with a lot of corrosion and holes in it. Repairs done, it was time to paint. Rustoleum Industrial in gloss white matched perfectly, and I was about to pull out the foam roller and tray. But then I remembered a YouTube video about spraying it with a cheap HFT gun. His spraying technique was awful, but the paint was supposedly dry to the touch in a half hour, and he was SANDING it the next morning. That seemed pretty unbelievable.

As you may know, Rustoleum oil-based paint is great stuff, but it takes a very long time to fully cure when rolled or brushed on. It will stay soft underneath for a long time, sometimes a week or more. I've learned to lay parts out in direct summer sun to cook it for several days before handling them much. Once cured, it is very tough stuff. Just be careful with it until then.

This guy thinned the paint with Acetone and added something called Japan Dryer, a paint hardener and drying agent. He said that's the trick to quick drying. Hmmmm.....

I pulled out the brand new HFT gun that had sat in the box for over a decade, and decided to try it. I mixed paint, acetone and a cap of Japan dryer, and filled the hopper. I dust-coated the transom and gave it a few mins for the solvent to flash off, as the video showed. Then I shot the first wet coat. WOW, it went fast, less than a minute to do the whole transom. I waited a few minutes between coats, and laid on 4 coats to give good paint thickness, and to use up the paint in the hopper. Satisfied, I went in and cleaned the gun, which took me awhile, since it was my first time doing it, and I didn't want to mess this gun up like the last one.

After cleaning the gun, at least a half hour, I went out to look at the paint. It still looked very wet. I KNEW it! Stupid video! Now I was going to have to wait days until I could get back to work.

But then I decided to touch a spot on an edge to see how wet it still was. To my absolute shock, it was dry to the touch. WHAT?!!!? I touched a little further from the edge, and it was dry. I touched the middle, and it was dry! You have GOT to be kidding me! The video was absolutely right!

It was about to rain, so I covered the boat. The next morning, I uncovered the boat and was amazed all over again. The paint was not only glossy and dry, but it was HARD, like it had spent a week in the sun. And it looked great. Now, I'm thinking of all the other stuff I can paint.

I thought I would pass this on for any other guys like me out there. Maybe I'll take some video next time.
 
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You'll never get me away from spraying. Those Harbor Freight HVLP guns are very easy to learn and lay down an excellent finish, it also greatly opens up your options in terms of paint choices.

If you do get a sag/run or an insect in the paint and haven't cleared over it yet, it is pretty easily remedied with a nib file. File it level, then progressively wet sand and work your way up to polishing with rubbing compound. If you do see a run forming, it's good to hit that area with some extra paint so you have more to work with, less risk of breaking through or creating a thin spot.

Oreilly's carries a hardener that works with most acrylic enamel paints and will reduce the drying time significantly. It also contains isocyanates, so don't skip the respirator. Nasty stuff.
 
Very good reminder for any who spray. It is not worth permanent lung damage, brain damage or kidney damage.

A friend's dad didn't like wearing masks. Because of this, he ended up with severe kidney damage from solvents in his bloodstream. They surgically removed the dead kidney, and he stayed in the hospital for a long time. Now he must stay far away from solvents and he has to be VERY careful about eating and drinking, as the remaining kidney is only partially working.

A lesson to be taken seriously!
 
I asked friends at a local marina, and they say definitely don't do it. Just do a good job of painting, and remember to clean and wax occasionally.

Ever see a car where the clear coat is starting to peel off? Looks terrible, and you have to strip it all off and start again. They say you are almost guaranteed to get that on a boat eventually. Thinking about it, I've personally seen where guys used clearcoat on their bass boats, and it looks GREAT, until it starts to peel. Use gelcoat on a bass boat. The same amount of work, but much better results.

On an aluminum boat, you might be able to use a full automotive-type paint system, and it would certainly look good. But IF it starts to peel, WOW, that would be a lot of work to fix.

My last three trucks, 1986, 1995, 2005 and now my 2019 F150 all were Oxford White, a single-stage automotive paint, and ALL of them looked great with an occasional wax. Some of the other colors with base/clear yellowed and peel after awhile. I'm glad I avoided that.

So, for me, the answer is no to clear coating. Paint, and after it cures, seal it with Nu-Finish. The stuff in the orange bottle that used to be on the TV commercials. GREAT stuff!
 
Another dumb question (hey, It's only August so I got a few left). Talking about aluminum boats, are you guys putting a clear coat on top of the paint?
You can, I cleared mine. Clear coat is undoubtedly a longer lasting finish in terms of UV exposure. Nothing lasts forever but single stage can oxidize rather quickly without pretty frequent maintenance.

Single stage hasn't been common in the automotive industry for many years, manufacturers started switching to base/clear in the 80s and 90s. I've had vehicles that were peeling terribly and others that held up pretty well, I think it's just a case by case situation with many variables and not only dependent on the application process.
 
You can, I cleared mine. Clear coat is undoubtedly a longer lasting finish in terms of UV exposure. Nothing lasts forever but single stage can oxidize rather quickly without pretty frequent maintenance.

Single stage hasn't been common in the automotive industry for many years, manufacturers started switching to base/clear in the 80s and 90s. I've had vehicles that were peeling terribly and others that held up pretty well, I think it's just a case by case situation with many variables and not only dependent on the application process.

I disagree that single stage oxidizes easily. Until the 90's, almost all vehicles used single stage, and many brand new work trucks use single stage paint, including mine, in Oxford White, a VERY tough paint:
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I just sold a 1972 Starcraft Mariner-V 18. It had the original olive green paint, and the hull paint was in excellent condition. I washed it and couldn't believe the shine it still had once I knocked the dirt off. The boat belonged to an old waterman who kept it in a slip in the Potomac river for many years. The gunnel tops were scraped up and the bottom was covered in barnacles. but the hull paint was in good condition, despite 51 years in the sun. I somehow doubt he ever waxed it. That is strong testament in favor of single stage paints.

Earlier this year, I did the floor in a 1969 Starcraft Mariner V 16. The paint was original and in good condition. It had a few dings and scratches, but looked amazing for 54 year old original paint. I doubt clearcoat would last that long out in the sun:

Resized_20230512_140500 (1).jpeg
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This makes me wonder... do any of the aluminum boat companies clear-coat their boats? If not, I would guess that is one less thing they have to warranty. If they have a few start to peel, that could cost them a huge amount of money.

All that being said, I bet yours looks good all cleared out!
 
Well, now you guys are talking about something I at least know a little bit about. I've painted just about anything you can think of. For fun and profit. I've use every type of applier on the planet I think. I've had great results with spray cans. It just goes on thin so if you intend to rub it out you must put down a bunch of coats. Like 7-10. Otherwise you run the risk of of taking it down to the base coat before you get it smooth. Lacquer is my product of choice. These days I prefer closed cell rollers and foam brushes.

Rustoleum is a truly wonderful product and has natural rust resistance that can't be beat if you're painting steel. As stated, you need to thin the crap out of it and put down a bunch of thin coats. Along with regular old paint thinner I add a shot of Penetrol. Depending on weather, you can generally start wet sanding the next day as opposed to straight Rusto which can take a month to cure.

I own one of those cheap HF guns and yes, it does a nice job, BUT it's a lot of hassle to clean it and it wastes a great deal of paint. Along with creating an unsafe environment to work in. You also don't really need to do much if any masking if you used the roller.

Defects in the paint including runs can easily be removed. There are many ways to go about it. One easy one is to cover the run with glaze, let it dry and then simply and carefully sand off all the glaze. When the glaze is gone so is the run. Just don't go any further or you may reveal the base coat.

As for clear coat.......I hate the crap. It eventually all lifts. 2 stage paint is a cheap way for body shops to skip the step of rubbing. IMO it yields an inferior paint job.
 
Now that is interesting. We are on opposite ends of the spectrum, Foam rollers have been my preference for years, but now I'm finding the joy of spraying.

One thing I thought was that spraying would waste a lot of paint, but it really didn't... at least on this project. In fact, I would have DEFINITELY used more paint with a roller and pan, even just what soaked into the roller and pan.

I like your glaze run removal trick. Thanks for sharing. I'm definitely going to try that next time I get a run in an otherwise nice paint job.

I've also heard that the auto makers switched to clear coat to save money. A nice clearcoat job can look really deep, at least for awhile.
 
Have decided to remove some of the carpeted areas of the gunnels and spray in the matching color. Should improve the look and ease of cleaning in the boat.. Another excuse to run the HVLP gun!
 
Defects in the paint including runs can easily be removed. There are many ways to go about it. One easy one is to cover the run with glaze, let it dry and then simply and carefully sand off all the glaze. When the glaze is gone so is the run. Just don't go any further or you may reveal the base coat.

This (using glaze) had me scratching my head until I googled it. Pretty neat trick. Thanks for sharing.
 
I've always loved to paint. When I was a little kid I painted my grandma's rental apt for her using a roller, pan, and OIL paint! Made pocket money in the neighborhood painting fences and garages. As for waste with spraying, It's unavoidable, but a gravity gun is a lot better than the old siphon guns. If you're using more paint with a roller, that a GOOD thing! It means you're putting on thicker coats. That's the rub on spraying. If you intend to rub it out, you need a bunch of coats. One other big advantage of the rollers is no orange peel. Save you a lot of time rubbing if you're going after a deep glassy shine.
 
I hate to paint, unless it's to make the rest of my work look good. I remodel a lot of kitchens, and I almost always include the painting. It really sucks to do a high-end kitchen with custom cabinets, stone, tile, stainless steel...and then have the homeowner do an awful paint job with dry spots, roller lines all over the ceiling, and wavy edges or worse. That can really ruin the effect.

Even so, I do enjoy spraying, for some reason. Arts and crafts for men, I suppose.

I currently have four coats of white on the transom and splash well area. It looks very acceptable. I still have to paint the tops of the gunnels, so I might rub the existing paint lightly, and then glass out the whole thing in a one spray.

I'm not sure why I care, as the original paint is decent, but nothing like the new part. If anything, I should be dulling it a little, so it blends in better. But if I wash and wax the whole thing, this boat should look pretty good.

This part is totally unecessary. I'm just having fun with my new toy. I'm probably just going to sell it when I'm done. :rolleyes:

But you never know... I might trade it for my Princecraft.
 
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As a follow-up, the transom paint cured into a nice, hard, durable finish that is super-easy to clean.

Thinned Rustoleum Industrial in a gallon can, Acetone and a capful of Japan Drier is a GREAT recipe!
 
You are so right thill! Rusto is great stuff. It is naturally resistant to rust and as you say with the right additives you can get awesome results. I painted a whole car with that stuff one time and once wet sanded and buffed it, it shined like lacquer! Just don't forget your additives or the stuff will take months to harden enough to wet sand, if at all.
 
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