Welcome to the third part of our online tutorial “Spray Painting without overspray” Today we are going to look at the pressure settings and how this affects overspray formation We are going to give you an overview, what happens when you work with too much pressure What happens when you work with too little pressure The effect is has on the spray pattern So that we will see how to get the pressure setting just about right The biggest problem, relating to overspray, is when people spray with too much pressure Unnecessarily too much pressure leads to more material than necessary being sprayed The material is also affected by the way too much is applied on it And all this leads to more overspray This is why it is so important to find the right pressure setting I will show you first the things to avoid with a very practical example How it looks like when I spray with too little pressure And what happens to the spray pattern when the pressure is too high And then in the end we’ll show you how to spray correctly How do you spray with an airless paint sprayer with the right pressure settings? A problem that we constantly hear from our customers is that people work with too much pressure or too little Generelly the problem is too much pressure What effects does it have? The material particles are moved at a very high speed and overspray is increased Which means you need to pay even more attention to masking And you use up more material And the machine, the nozzles and the gun are subject to heavier stress too Which leads to increased wear and tear The opposite problem would be when you work with too little pressure This means an uneven spray pattern, especially on the margins On the edge you would have more material While in the inner area the spray pattern is spotty We are going to take a look right now First we will spray with too little pressure, like 50, 60, 70 bar So that we get the picture of what it looks like And then we will see what’s the result when you work with the maximum pressure of the machine We are working here with a PS 3.29 by Wagner Which has a maximum pressure of 221 bar And then we will compare too much pressure with too little pressure Let’s get started with too little pressure now! We are now at 80 bar And we will go to 60 bar while spraying Of course it does not have much sense with a normal spray nozzle but it is just done to illustrate here We see here very clearly an uneven spray pattern This very typical stripe formation when people work with too little pressure Or when the nozzle is worn out. So it is not just with too little pressure If you the pressure is correct and the spray pattern looks like you, then you know have a problem with the nozzles In the middle the material has not been It is very easy too see here that one has worked with too little pressure And now, to compare, we will increase the pressure and see what happens and let’s do it with max. pressure So here with max. pressure Ok, it does not looks beautiful but it is perfectly fine for our purposes We have a lot of material here Like, a lot of material And the spraying is very strong Of course you have a relatively even spray pattern But you would employ here really much more material than necessary And this leads to an increased overspray formation Here we spray just for a few seconds and it may not appear to be be big thing But if we had a larger surface or an entire room to spray paint, this would be very very clear That we have too much overspray So we have just seen what is the results when you work with too little or too much pressure And this affects the spray pattern and the overspray The question now is: how do I obtain the optimal pressure setting Which pressure level is right for my material, for my nozzle, for my project, for my machine? It depends as usual on many factors Delivery rate of the paint sprayer, size of the nozzle, viscosity of the material Even the temperature of the material and the outside temperature So it is always good to try it out gradually, in order to find the right pressure level You can do it gradually So now we will show you how to do it So the next question is: how do we get the pressure right? Basically you begin with a relatively low pressure, you do a couple of test sprays Just on some cardboard, or on the side, on some piece of paper Especially when you are working with a new material, to try it out And you raise the pressure gradually At the beginning it will rather look like this Where the spray pattern is uneven And you will notice that the more you raise the pressure That the spray pattern becomes better And when you think you can be happy with the spray pattern, you have reached the right pressure level So the most important thing is that the material is applied evenly We will make a couple of tries We will begin from 100 bar and then we will gradually increase the pressure To find out what the optimal pressure level is So we begin from 100 bar, I will do just a couple of little stripes So that we can compare them So here not really the best of the applications The spray pattern is patchy Here again, there is too much material on the edges So now we will just raise the pressure, let’s go to 130 bar Here compared to 100 bar we clearly have a better application of the material Let’s raise the pressure a bit more then, 150 bar, maybe even a bit more, because this material is rather thick So we have now a pressure of 160 bar And I am pretty confident that we will get a good spray pattern It certainly looks much better now We have a rather uniform spray pattern Maybe we could raise the pressure even a bit more, but I believe we see here very clearly How it looks like like when you have too little pressure And we see a progression here And this illustrates very clearly why it is so important to find the right pressure So, as we have just seen how too little pressure affects the spray pattern For example in that too much material is sprayed on the edges So the question is how do I reach the best possible pressure level You can try to test the pressure with water too Just with the gun and the paint sprayer with water You keep the trigger pulled and you slowly raise the pressure In this way you can easiliy see how the spray jet develops At the beginning water will come out of the nozzle, then slowly We will have a spray jet, at first very uneven and then You will reach a point where in the middle you will have just about as much material as on the edges Raise the pressure above this point is unnecessary And only leads to unnecessary overspray formation So you can test with water gradually and easily This is a good practise for beginners So now we have an overview of the subject “Pressure setting and overspray reduction” In the next video, part 4, we will talk about airless spray nozzles If you have questions, send us a message or call us through Bye bye.