Spraying Distance/Orange Peel

[88Porsche944]

I have a question. It may be an individual thing, but what is about right for a spraying distance, I'm using an airbrush. I keep getting light/medium orange peel.

I'd post a photo, but I don't have a camera.

Trevor

[hirofkd]

It depends on the pressure, paint thickness and duration (how quickly/slowly you move the airbrush across the object).
In other words, you kinda have to find the optimum balance between those four factors; distance, pressure, thickness and duration.

I'd start playing with the paint thickness, by adding a bit more thiner, and see if it makes any difference.

You can also use different thicknesses progressively, like starting with a relatively thick mixture, then as you add more layers, you add more thinner. That's what I usually do, and my final coat is almost 80% thinner and 20% paint.

Another important thing is body preparation. Some primer tends to leave the surface uneven, which increases the risk of orange peel at the time you spray base color or clear coat.

[MPWR]

Originally Posted by hirofkd

you kinda have to find the optimum balance between those four factors; distance, pressure, thickness and duration.

Spot on. So the best way to handle it all is to treat several of these factors as constants, and vary only one or two.



If you're airbrushing now, then ignore spray distance. It's the least precise of these factors to control, so it's best to use a constant spray distance for all of your airbrushing and adjust the other factors. You will very quickly find that you have a natural spray distance that works for you- the position that is most comfortable for you to work in. Find it and use it. Varying spray distance is for people with spraycans- who simply cannot control other variables.

To avoid orangepeel in spraying:

1. Make sure the primed surface you're spraying on is PERFECT. No texture, seams, etching, debris, scratches, etc. Sand it until it is absolutely even. This is the most critical part of painting, and is where most of your time and effort should go.

2. Keep your spray distance constant- see above.

3. Spray with the lowest pressure you can use to consistently atomize the paint. A good gravity feed airbrush should do very well below 20psi, and may work in the neighborhood of 15psi. if you don't have a regulator, get one (they're only $20-30.) Pressure required will very with the type of paint you are using.

4. Use the maximum amount of thinner you can before the paint runs/pools. This is judgment and experience (so get to practicing!). Keeping the paint thin allows it to spread out and level as it hits the surface- instead of hitting the surface in partially dried blobs, which is what leads to texture.

5. Adjust your paint flow rate with needle position in the airbrush (you're using dual action, I assume). Start light, and increase as you need. This is the variable you are using the most to control the performance of the paint. It's always best to use too little than too much, but experience will quickly tell you how much paint you should be flowing.

Controlling the flow rate with the airbrush (like it's designed to do) is far easier and more effective than trying to do it with spray distance.

[88Porsche944]

Thank you both.

Yes I am using a dual action airbrush. I'll get to practicing!

Trevor

[shonin]

The final 'wet' coat is usually where I struggle the most with orange peel.

I usually use less thinner for final wet coat of acrylics and slow down but increase volume of my strokes with the airbrush to get that wet look. Looks good when wet only to dry in light orange peel.

Any suggestions?

[MPWR]

Originally Posted by shonin

The final 'wet' coat is usually where I struggle the most with orange peel.

I usually use less thinner for final wet coat of acrylics and slow down but increase volume of my strokes with the airbrush to get that wet look. Looks good when wet only to dry in light orange peel.

Any suggestions?

Sure, that's and easy one.

Don't apply a final wet coat!

The final coat of paint or clearcoat are the lightest ones I apply. They serve only to cover/fill any fine scratches from sanding.

Spraying a final heavy (especially a less thinned one) is a great way to give up control of your spraying. It's like asking for trouble. And if you're waiting for the last coat to make things perfect, it's waaaay too late.

[shonin]

but that last wet coat makes the paint soooo glossy

[CrateCruncher]

I can only think of one thing to add to this excellent discussion. I've found that using a very bright light (like a 100w desk lamp) at a low angle to the surface while spraying will give me instant feedback on how well the airbrush is covering and how well the paint is levelling out as I spray.

P.S Compared to maintaining an '88 944 paint texture is a piece a cake. ($$$$YIKES$$$$)!

[Didymus]

All else being equal, holding the spray can nozzle closer to the car will produce a glossier surface with less orange peel. That's because the paint doesn't have a chance to dry out and clump before it hits the surface.

When you're holding your spray can close, you have to move it pretty fast, and that means you can't check the surface as you go. There's a greater risk of too much paint (sags and runs) or too little paint (poor coverage).

It's a high wire act, but it becomes less risky with experience.

It's safer to keep your distance and rub out the orange peel after the paint cures.

Ddms

[MPWR]

Originally Posted by shonin

but that last wet coat makes the paint soooo glossy

Sure, if you say so.

What makes the paint soooo glossy is having it smooth. To do it properly takes some patience, time, and a little bit of effort. Slapping on a heavy wet final coat on and hoping it comes out perfect is a bit like putting all the parts of a model in a box and shaking it, and hoping the model comes out of the box properly built. You might get lucky occasionally- but really it's a poor approach to building models. Painting, like building, should take several days- not minutes or hours.

Originally Posted by CrateCruncher

I've found that using a very bright light (like a 100w desk lamp) at a low angle to the surface while spraying will give me instant feedback on how well the airbrush is covering and how well the paint is levelling out as I spray.

Absolutely right, and an excellent point! This is the best (and only) way to evaluate what the paint is doing as you spray.

Originally Posted by Didymus

holding the spray can nozzle closer to the car will produce a glossier surface with less orange peel.

Whlie that may be, I don't think we were talking about spray cans.

[Didymus]

Originally Posted by MPWR

Whlie that may be, I don't think we were talking about spray cans.

True, we weren't, but the principle still applies: to prevent OP, the paint should be wet when it lands on the surface. That doesn't mean it has to be a "heavy wet coat." I agree with Shonin - a (thin) wet final coat produces the smoothest finish and the best gloss.

Ddms

[ZoomZoomMX-5]

Originally Posted by Didymus

I agree with Shonin - a (thin) wet final coat produces the smoothest finish and the best gloss.

Ddms

I do as well, when I'm clearcoating as I approach my final coats I add more thinner to the clear, shoot it real close and real fast, gives great thin/wet coats, helps the paint to flow w/o creating any more texture than might be in the layers below. Experience is key; get it just a little off (mixture, distance from subject, pressure, paint flow), and it may run, or spray too dry and hence with texture. Good painters know where the sweet spot is and can achieve it with great results.

[Eric Cole]

I know this is probably going to come out wrong but it all comes down to experience regardless of your method of application, i.e. airbrush or spray can.

By experience, I don't necessarily mean "a period of time or number of years". What I mean by experience is the ability to look at the paint as it's being applied to the subject and understand what's happening, then to learn how to control the airbrush or spray can to give you the result you want.

I know, sounds obvious but I'm not referring to just a glossy/shiny finish. I'm talking about learning to control the AB or spray can to get the result you want whether it's glossy, grainy or even a rough texture. All can be achieved with the same tool but only if you know how to control it.