NFT5 wrote:

jerlands wrote:it honestly doesn't look impossible

Love it when we get a noob with a sense of humour.

DarrelK wrote:You will end up cutting and buffing your first paint job.....

... and your second........ and your third....... and your fourth.......

I plan to spray the plastics first... I should be able to tell something after that... no matter... I don't think I'd flowcoat those anyway?...

NFT5 wrote:A figment of the imagination, I'd suggest. But gets lots of Youtube views and that means income from advertising, not to mention sales.

If you just run air through a gun you'll get quite different pressure results to that when you run thinners or, indeed, paint. Even something like setting your spray pattern can't be done properly unless done with the actual paint that you're using. For example, if I run thinners through my Pro Lite, without changing the settings for air, fluid and fan, then I'll get a fan that is heavy at the ends, i.e. too much air for the viscosity of the thinners. But, if I run paint through, again without changing the settings, I'll get a nice even pattern but my air pressure readings will change.

It's true that, after many years, I can tell if a gun is not right by the sound it makes, but to set it up properly I use paint and spray on to a piece of masking paper that is permanently on the wall of the booth.

id like to know why your air pressure changes ?

PainterDave wrote:id like to know why your air pressure changes ?

I don't think air pressure changes in the sense of nozzle air pressure. What changes is the amount of air hitting the panel rather than misting away. That is what I understood out of it, if I've explained it correctly. The further out from the panel and I think he said the greater the chance the paint molecules collide. Apparently the best point to apply for good atomization is that zone he described. But, that makes me curious when I see guys blending with the gun quite a ways from the surface?

PainterDave wrote:id like to know why your air pressure changes ?

I use regulators with gauges on every gun, mainly because once set it's just a matter of a quick check to make sure everything is still ok. Generally I use the same gun for the same product, i.e. dedicated guns for base, MS clear, HS clear etc.

So, if I connect the gun to the air hose without anything in the cup and pull the trigger then the air will flow through the gun without any restriction (other than the obvious - size of apertures, caps etc.). If I then put, say, straight thinners in the pot and pull the trigger I'll get a spray pattern that (because everything was set up for, say, MS clear) is a bit heavy in the ends but the pressure will change a little because there is some resistance to the free flow of air, i.e. it now has to expend some energy on atomising the thinners.

At the extreme end, if I was to put HS clear in the pot I'd probably need to increase the air volume a bit to get the flow and pressure needed to atomise the heavy product. I could do this either with the cheater in the base of the gun or with the regulator adjustment, or both, depending on the gun. Maybe even swap a 1.3 for a 1.2mm tip to really bust the clear up.

My point was that spray pattern should be checked with the product that you are spraying. Initially I do a sight check, just looking at the pattern in the air, but then I do a check on some paper on the wall. Sometimes even being a warmer day can have the effect of reducing viscosity enough to need a small tweak in settings to get that pattern exactly right. Conversely, paint that's a bit cold can be like treacle.

The idea that you can adjust your gun, by sound alone, using just airflow bouncing off a surface, is, in my opinion, ridiculous. Even the concept that paint droplets will more likely collide at a greater distance from the panel goes against every law of physics that we've so far uncovered. As you know, the further away the gun is from the panel the greater the distance between droplets at or close to the panel, so the likelihood of collisions will decrease, not increase. Further, since the droplets are being projected in what are basically straight lines, they're unlikely to change direction half way there and go looking for another droplet to run in to. Perhaps different at the end of the influence of the air carrying the droplets, but we're not talking about that here.

As OP pointed out, drop coats are done at increased distance and current best practice from Axalta training is to do what they trained us not to do a few years ago - blend with wrist action, turning the gun from perpendicular. Of course, waterborne and always on a wet bed so P240 edges to your blend are not likely, but I doubt that video would have considered that.

jerlands wrote:but I'm still confused about paint compatibility.. I believe the car was painted in waterborne

Your in The Republic of California the only Paint you can buy in California is water born.

As far as I know? I could be wrong though Its been a while...

NFT5 wrote:The idea that you can adjust your gun, by sound alone, using just airflow bouncing off a surface, is, in my opinion, ridiculous.

I don't even think I implied that. finding the sweet spot in the gun with that particular tip is done after setup.. then things are further adjusted... it's a never ending friggin' adjustment it seems. What Kevin Tetz explained I thought useful... you may not since you may not need that particular tool...

jerlands wrote:What I thought interesting was the idea he presented about atomization and how you can hear when all the air has just started hitting the panel and not misting away. at least, that's what I got out of it, that paint molecules tend to merge together if too far away but I think if too close it's just really a matter of effective spray pattern?

This is what I was responding to. You didn't give us a link to the video and I'm not inclined to waste time searching for it.

Maybe you just didn't understand, but what you're suggesting here is, umm...........ridiculous.

How can one talk about atomisation when using an empty gun? Without experience it's not your fault, but any of the painters on here will tell you that transferring the paint from the gun to the panel isn't like this at all.

Air doesn't just "mist away". You're spraying at (say) 30psi. The air, carrying the atomised paint, is absolutely blasting out of the cap. Unless you're standing 2-3m away it's hitting the panel. Some bounces back - that's overspray. We try to limit this by not over-pressuring our guns, but a certain amount is a compromise made for finish quality.

What you want to achieve is a regular pattern (usually cigar shaped, but depending on your gun may be squarer at the ends) in which the atomised drops of paint are distributed evenly and fad away equally at ends and sides. This will allow you to put on an even wet coat that won't be excessively orange peeled, or dry or run off the panel. The distance at which you hold your gun will depend on the gun, your experience and the product you're spraying. For example I might be 200mm from the panel with basecoat, sometimes even 300mm, but come in to between 100mm and 150mm when clearing. All depends on the job, the product and the gun, plus the finish or effect that I want to achieve.

As to hearing when the "air is just hitting the panel", that's impossible since it will be hitting the panel from a long way off and only the rate at which it hits will increase with lessened distance. As I said before, it changes with the type of paint you're spraying anyway, making the empty gun air only exercise not just a waste of time but potentially misleading you as to the correct gun settings, or even initial settings.

Spraying on to a piece of masking paper on the booth wall is the only way that you can really get your gun settings right.

NFT5 wrote:

jerlands wrote:What I thought interesting was the idea he presented about atomization and how you can hear when all the air has just started hitting the panel and not misting away. at least, that's what I got out of it, that paint molecules tend to merge together if too far away but I think if too close it's just really a matter of effective spray pattern?

This is what I was responding to. You didn't give us a link to the video and I'm not inclined to waste time searching for it.

Maybe you just didn't understand, but what you're suggesting here is, umm...........ridiculous.

it's not that I think Kevin Tetz is industry standard.. but what he spoke about made sense to me.. I thought it was something taught... anyway... I will search and retrieve said video...

NFT5 wrote:Maybe you just didn't understand, but what you're suggesting here is, umm...........ridiculous.

Lot's of video's out there... this might take a while... but I think it is worth discussing...

NFT5 wrote:

jerlands wrote:What I thought interesting was the idea he presented about atomization and how you can hear when all the air has just started hitting the panel and not misting away. at least, that's what I got out of it, that paint molecules tend to merge together if too far away but I think if too close it's just really a matter of effective spray pattern?

Maybe you just didn't understand, but what you're suggesting here is, umm...........ridiculous.

I've been unable to embed the video.. here's the link...
https://youtu.be/coZ6NA-KJdo?t=395