It was above 50F, but. . .

PJH

Well-known Member
I'll start off by saying that I'm not a painter. Also - I don't have an ideal painting area - gravel/dirt floor and unheated metal building. John Deere paint and thinner. Pressure pot sprayer.

It was hovering around 65F degrees yesterday, but the humidity was pretty high - it even sprinkled a few times during the day. Most of the paint dried looking pretty good - nice coverage and shine - but the last pot I sprayed dried with a "frosty" look in some areas. There's a couple of pics that show it if you look close - on the edges of bolt heads, the belt pulley, and the oil cap. Everything had a nice wet shine last night. Small parts looked real good this morning.

The concrete was sweating when I opened up the shop this morning.

What do you think caused this "frosty" look?

I think I can just re-coat it under better conditions - what do you think?
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Thanks Glennster - I suspicioned that was the cause. I'm hoping it will stick, even though it has no shine. Maybe I can overcoat it at a later time. All of the blushed areas are easy to get to. I'm trying to get it back together, and wanting to get color on the inaccessible areas first. This poor tractor always gets moved to the back burner, in terms of importance.

Thank you for all of the good advice that you give to those of us who don't know what we are doing. I read all of your paint and bodywork posts. Very interesting!
 
I would agree with Glennster.

I do paint when it is cooler out, but make sure paint and metal are both warm and it is dry.
 
i would let it go till spring when you can get some heat on it. enamel is a funny critter, and i am assuming you used a dealer paint from john deere ect. that is a modified alkyd enamel. without hardener it takes a loooooong time to dry, and even then will be soft in a hot sun. you can try in the spring hitting the blushed areas with a red scotchbrite pad and re-shooting it. mask off the rest of the tractor because the overspray will get everywhere, and give you a dull finish. in the old days of synthetic automotive enamels , like duponts dulux, we would heat the paint up to about 120 degrees in a water bath on a hot plate, load the gun and shoot. back then it took 30 days to get a good dry. i try and advise new painter to stay in the mfr product line. use their primers, sealers, hardeners and reducers and follow their recommended proceedures. . a lot less chance of running into problems. no need to re-invent the wheel. its kinda like getting a farmall cub to pull a 9 shank chisel plow. you can throw a ton of money at the tractor to try and get it to work, but way easier to get a bigger tractor!!
 
It's just blushed from the high humidity. The dull spots will need another coat when the weather is dryer. If you can't do that and the blush isn't bad sometimes you can buff it out. You would need to let the paint dry for a month before attempting that.
 
Thanks to everyone for the good advice.

I'll give it a re-coat in the spring. Mainly wanting to get it back together, and some places are not easy to hit with parts in the way. The blushed areas are out where I can get to them later.
 
What happens is water from the air literally gets into the paint and floats to the surface and clouds the sheen. It's usually very superficial and could be buffed off it that is any easier.
 
I sympathize. This happened to me last week. Weather was perfect, unseasonably warm, tee shirt weather so I shot everything I could. By the third coat, my gun clogged up and messed up a few pieces (I had been having trouble since I shot some 1K sealer that was a bear to clean out and kept proving that anytime I'd paint for a bit). I let most everything else dry enough to move and had interruptions until it was late in the day before I got back to fix the issues with the parts that had been messed up. I knew it was too late in the day, but I was determined to push through, and reshot them anyway. Before I could pick them up to put them back in the shop, the weather turned dramatically. When I came back up in the morning to see how they fared, those parts shot in the evening all were blushed.

I decided to experiment, treat it as a "what if I had to use the parts as is", since everything will now need to be scuffed and recoated so I can shoot clear. I had to order a new gun because I'm fed up with this one and between that and weather, I've missed the window to clear coat anyway. After a not-too-reasonable dry time (a few days), I took the blushed wheel guard and in a test spot, sanded with 400, 1000 then 1500 grit, then rubbing compound, then guitar polish (about the same thing I do with guitars to get a mirror finish and it's all I had, a warning here is if you test like that, polishes contain stuff that demand you use naptha or acetone and then sand if you plan to repaint over the spot as I do). It frankly doesn't look bad at all and if I did have to live with it, it would be okay. The exercise caused me to realize that I wasn't getting good leveling, but that is another story.

While I doubt the blushing hurts the integrity of the job, the problem is that if you had to do everything that way, it would use a lot of time and consumables and is a lot of work. Worse, on a tractor, the nooks and crannies would never shine as well as the open surfaces, you just can't get at them with the elbow grease necessary. Of course I'll be sanding all that back before recoating with base so I can clear coat.

My honest opinion that you only will get "good enough" by buffing and polishing a blushed part. I don't have the time to prove that, but if it is possible, the time would be more than scuffing and shooting again. I invested probably 10 to 15 minutes into a 6x3 inch area and still didn't feel it had the luster I'd really want out of a new paint job. In that time, I could have scuffed the entire wheel guard and shot it again.

The photo shows the wheel guard on the left that wasn't painted in the evening, and the one on the right that was. You can see the right hand one is flat orange from humidity damage.

mvphoto5767.jpg
 
Could be overspray, after least cost of paint is applied give the whole thing a quick coat of the thinner. The thinner will open up the paint, let the overspray sink in, and its all shiny no "flat" spots. I do that after any enamel paint job, and it works good (old painters trick).
 
That's interesting - you pretty well described my experience. It was getting late and I knew I shouldn't load that gun one more time, but I hated to quit. It's amazing how much difference there can be in those two fenders when everything else is the same.

I'm convinced that the easiest correction is to wait for a warmer/dryer day, scuff and re-shoot. It sure slows down the progress though.

If I was trying to do this for a living, I'd starve to death.

Thanks to all for the comments and advice. I'm slowly learning.
 
(quoted from post at 19:30:46 11/08/17) That's interesting - you pretty well described my experience. It was getting late and I knew I shouldn't load that gun one more time, but I hated to quit. It's amazing how much difference there can be in those two fenders when everything else is the same.

I'm convinced that the easiest correction is to wait for a warmer/dryer day, scuff and re-shoot. It sure slows down the progress though.

If I was trying to do this for a living, I'd starve to death.

Thanks to all for the comments and advice. I'm slowly learning.


I even do the same thing when its 90 + degrees with enamel paint. Also if you are going to respray it use gloss hardener in the paint, the shine will last a whole lot longer, and its less likely to be scratched.

My MF135 I painted using the gloss hardener, and the quick last spray with the thinner only.
5802.jpg
 
What I do is keep a thermometer like this in the shop that has a humidity gauge on it and I don't paint anything if the humidity is 70% or more.
a177607.jpg
 
Stephen, I have a digital humidity gauge inside the shop, and it said 74% on the day I painted. I don't know if it would be the same out where the tractor was, but the day was damp and drizzly - I should have known better.

By the way - I think you are the one who told about using the pressure pot sprayer - I got one from Harbor Freight, and it worked real good, but it makes a LOT of overspray (compared to my HVLP gun). That's probably because I didn't have it set right - the pattern was good, and I like that it will spray upside down - nice for getting in the nooks and crannies.

Thanks to all of you guys for the valuable advice.
 
ptfarmer, that's an interesting idea.

Thanks for the advice - I'm trying to soak it all up.
 
It sounds like you may have had too much pressure in the pot. I don't know exactly how that sprayer is rigged but you should be able to adjusted it to where it pours out paint like a garden hose or puts out the volume like a cup gun. With the large tank I have I think it's less than 1 psi difference between it not spraying and gushing out.
 
This gun is touchy - it had a low pressure threshold around 35 psi where it would get intermittent and spitty. I found a sweet spot closer to 40 where it was consistent and it never gave any problem. It put out more paint that I was used to, but I learned to move faster and got along with it ok.
 
(quoted from post at 08:57:23 11/08/17) I sympathize. This happened to me last week. Weather was perfect, unseasonably warm, tee shirt weather so I shot everything I could. By the third coat, my gun clogged up and messed up a few pieces (I had been having trouble since I shot some 1K sealer that was a bear to clean out and kept proving that anytime I'd paint for a bit). I let most everything else dry enough to move and had interruptions until it was late in the day before I got back to fix the issues with the parts that had been messed up. I knew it was too late in the day, but I was determined to push through, and reshot them anyway. Before I could pick them up to put them back in the shop, the weather turned dramatically. When I came back up in the morning to see how they fared, those parts shot in the evening all were blushed.

I decided to experiment, treat it as a "what if I had to use the parts as is", since everything will now need to be scuffed and recoated so I can shoot clear. I had to order a new gun because I'm fed up with this one and between that and weather, I've missed the window to clear coat anyway. After a not-too-reasonable dry time (a few days), I took the blushed wheel guard and in a test spot, sanded with 400, 1000 then 1500 grit, then rubbing compound, then guitar polish (about the same thing I do with guitars to get a mirror finish and it's all I had, a warning here is if you test like that, polishes contain stuff that demand you use naptha or acetone and then sand if you plan to repaint over the spot as I do). It frankly doesn't look bad at all and if I did have to live with it, it would be okay. The exercise caused me to realize that I wasn't getting good leveling, but that is another story.

While I doubt the blushing hurts the integrity of the job, the problem is that if you had to do everything that way, it would use a lot of time and consumables and is a lot of work. Worse, on a tractor, the nooks and crannies would never shine as well as the open surfaces, you just can't get at them with the elbow grease necessary. Of course I'll be sanding all that back before recoating with base so I can clear coat.

My honest opinion that you only will get "good enough" by buffing and polishing a blushed part. I don't have the time to prove that, but if it is possible, the time would be more than scuffing and shooting again. I invested probably 10 to 15 minutes into a 6x3 inch area and still didn't feel it had the luster I'd really want out of a new paint job. In that time, I could have scuffed the entire wheel guard and shot it again.

The photo shows the wheel guard on the left that wasn't painted in the evening, and the one on the right that was. You can see the right hand one is flat orange from humidity damage.

mvphoto5767.jpg


Did you use gloss hardener when you painted it?
 
(quoted from post at 23:32:20 11/09/17) I didn't use a hardener - I don't have the proper breathing equipment.



A good breathing mask is good to have even when you don't use a hardener. When you don't use a hardener do not try to sand, or buff the paint out. On enamel without the hardener only the "outer skin" of the paint fully dries, and the chemicals in the paint underneath never fully dries. Once you break through that dry outer surface the paint will never stay shiny. I ruined my first enamel paint job many, many years ago doing that but thinking I could sand, and buff the paint to make shine even more.
 
"Pressure in the pot"

I re-read your post - I was fooling with the main regulator, trying to get a sweet spot. I probably should have paid a little more attention to the regulator on the pot itself. Thanks for the tip - the directions that came with it are pretty vague.
 
So you just shoot straight thinner through the spray gun to give it a light coat?? Interesting.. I may give that a try on my next painting project
 
About the only paint that would work on is lacquer. On enamel paint thinner would just lay on the surface once it has flashed off. You would only have a very few seconds to dissolve in enamel overspray.
 
(quoted from post at 12:31:21 11/15/17) About the only paint that would work on is lacquer. On enamel paint thinner would just lay on the surface once it has flashed off. You would only have a very few seconds to dissolve in enamel overspray.


No, the thinner will "open up" the paint until it flashes off, before the thinner flashes which is very few seconds it allows any overspray to soak into the paint which will bring the shine back after the thinner flashes. It will work on lacquer also, but if you want a really, nice, shiny paint job with lacquer you have to sand, and buff the paint afterwards. Lacquer paint is not as durable as enamel, plus as I said before a lacquer paint job needs to be sanded, and buffed to get good shine from it. Since lacquer is thin you need to apply a lot more coats, when lacquer was the paint for custom paint jobs you put on about 20 coats because of what you loose from the sanding, and buffing afterwards. Enamel you don't have to sand, and buff to get a good shine so you only need about 3 coats.
 

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