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Orange Peel


murray*
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Hey there, I've read conflicting reasons as to what causes this. Eg if the paint pressure is too low, and also I've read it occurs if the paint pressure is too high. I'm using an old 1950's spray gun. Is there a way to estimate pressure based on how far the paint comes out? I figure 1) get the pressure right and then at the right distance I should get better results. (eg no orange peel) Any feedback appreciated thanks

ps I've read through the tutorials etc but there doesn't seem to be info on pressure estimation. etc

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Hey there, I've read conflicting reasons as to what causes this. Eg if the paint pressure is too low, and also I've read it occurs if the paint pressure is too high. I'm using an old 1950's spray gun. Is there a way to estimate pressure based on how far the paint comes out? I figure 1) get the pressure right and then at the right distance I should get better results. (eg no orange peel) Any feedback appreciated thanks

ps I've read through the tutorials etc but there doesn't seem to be info on pressure estimation. etc

Murray,

Actually, both can cause this problem, but the most common cause is from a surface that is not clean before spraying. Such as maybe body oils or waxes. It is more likely to be seen after the first coat and the adhesion between coats is not doing what it should. Improper sanding or sanding with too fine of paper will also cause this, again an adhesion problem. Much like water beading up on your car after waxing it. What are you spraying, what kind of gun, do you have inline moisture traps, what was the temp and humidity. All of these effect a spray finish. To say this and only this causes a specific problem will not help you get the results you are seeking as many things can cause this, as well as other problems.

Mike

Edited by MiKro
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I just took a class with House of Kolors Technical instructor, the mighty and powerful Brian Lynch. He's the guy the rockstar painters go to for help, advice, and working out paint plans. He has worked consulted for Trick My Truck, Monster Garage, and countless show cars.

He painted a guitar for me in the class with HOK's Orion Silver under a Orange Candied Metajewels, then cleared it in an open conference room(don't ask). Zero orange peel, better than factory from the big guys. It brings the bling.

A good gun helps, but a cheap one will do if it has the right tip size, sprays correctly, and is adjusted right. Also think about your air supply and how you regulate and filter it. With a cheater valve and not a regulator on the gun you will not have a constant air supply.

The old guns are a mystery to me, I only use and have read up on the HVLP guns. They are more efficient and create less overspray.

Here was his take on orange peel:(some of this applies more to 2k urethanes, mostly its universal)

1. Read, understand, and follow the tech sheets.

2. Spray a test pattern to make sure your gun is dialed in. Right fan size, right atomization, equal amounts of paint throughout the pattern, and a nice oval shape. Google it I'm sure you can find material on dialing in a spray gun. I bet DeVilbiss has it on their site.

3. Next you need to maintain proper distance with the gun. This will be in your guns manual. Typically my guns instructions say 6" away for a 6" fan. A guitar he recomended a 4-5" fan.

4. Next its all about laying down a single flowing coat of paint. Don't spray paint till it flows, spray so it will flow. This means a quick application of an even coat of paint. Your tendancy will be to put on too much paint. A guitar takes about 2 minutes to spray a coat. T

5. Leave it alone until it flashes. Don't speed it up, flash time is where the solvent gets out of the way so the molecules in the paint can lay down in a nice smooth pattern. This means don't blow it dry with the gun, don't super heat it, just don't. I know production shops do this on cars, but look at the peal they leave, because they are trying to emulate factory quality.(or lack there of) You are aiming for custom quality, so time matters less than quality.

6. Recoat within the proper times from your paint, per the tech sheets.

7. Buff lightly, enjoy. Don't forget to clean your gun.

Hope this helps, I know it helps me to type it out and think about the process.

*edit*

Finally, uploaded my pictures. This is straight off his gun.

DSCF0130.jpg

DSCF0139.jpg

DSCF0140.jpg

Edited by syxxstring
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Hey thanks for the tips, all this advice is valuable. I went against what I'd already read and didn't sand back the paint before laying the lacquer. (reasoning- I didn't want to sand through the paint......this is the second attempt at painting this guitar, the first was a disaster so I stripped it back and started again. Just didn't want to go through the painting process again so I thought I'd get some clear coats on and then sand.) This may have been the problem, but like I said in an earlier letter I've never used a gun before so I think I've got some other aspects to understand also. The first thing I tried to paint was a antique chest I restored (back to bare wood), I got a similar finnish on that also. The gun is really simple (looks great, I love that old 50's stuff, ha), a vacuum cleaner thing that sits on your back that connects to the gun (a modern version that looks similar is the hvlp gun at this site (http://www.rockler.com/product.cfm?Offerings_ID=10469&TabSelect=Reviews). Pressure/fluid control at the back. Basic question can I adjust the fan size a gun like this? I can move the air horns......I spent about a week cleaning this old thing up, internally it's all brass all it all screws apart (love it!). This is my first attempt at spraying so it's all a steep learning curve. I'm using an oil based lacquer. I'm at the stage now where I've sanded back a little and thought I'd go for a thinner coat/lighter pressure coat, but I think I may do a few more tests first

Thanks again

ps I mixed about 20% thinner with the varnish

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As for thinner mixture, that will depend on your product. Follow the tech sheets, especially if they have information for a conventional gun.

Adjusting the fan should be possible, you should have 2 controls up top on the gun one is fluid the other is the fan size. If you have a third one it is for the air, leave it wide open and adjust either using a regulator at the gun or air compressor.

For your set up I'm not sure what to adjust how, since I think for that stile gun you may have to adjust the fan or fluid control buy the viscosity of your material.

One thing to note a conventional style gun transfers about 50% of what you put through it to the surface you are painting. In comparison HVLP guns are about 80%, and some of the newer LVLP guns are even more efficient. What that means is a HVLP setup will pay for itself if you paint a lot and create a lot less overspray to clean up. If you don't spray a lot or use cheap material it may not matter to you, seeing as my clears and paints can run up to $200 a gallon...

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Well I tried again today with a thinner lacquer (1:1). I sprayed a little closer to the guitar/less pressure, I got less orange peel but a couple of drips. In a weird kind of way this is progress as I suppose next time I'll make the mix maybe 3:1 and take it from there. Thanks again for the feedback

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  • 3 weeks later...
Well I tried again today with a thinner lacquer (1:1). I sprayed a little closer to the guitar/less pressure, I got less orange peel but a couple of drips. In a weird kind of way this is progress as I suppose next time I'll make the mix maybe 3:1 and take it from there. Thanks again for the feedback
You may need to change to a different tip size.

Just a thought!

MK

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Well I tried again today...

Try again and again and again and again and again and again and again and again and again and again and again and again and again and again and again and again and again and again and again and again and again and again and again and again and again and again.

That's how you'll best develop the feel for this.

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