Re: Question about Orange Peel

Posted by Rod (NH) on July 27, 2005 at 16:47:30 from (64.140.200.138):

In Reply to: Re: Question about Orange Peel posted by CNKS on July 26, 2005 at 19:42:00:

I find your problem somewhat interesting simply because I don't think I've ever experienced it. I would never think of doing a hood perpendicular to the long side - it would seem to be oh, unatural to me :o). The only time I've gotten into doing a hood crosswise is with my truck - and then only because the Centari that I was using at the time recommended a cross-coat technique where the second coat is applied perpendicular to the first. I think that's kind of wierd since I believe it is impossible to do on a full sized vehicle with the hood in place. My arms are not six feet long. Most people's arms are not that long either. The hood I did was done off the vehicle so I could do the cross-coat technique fairly easily. I did my B hood from the tractor similar to the way you mention. Lengthwise passes starting at the middle of the top, proceeding down one side, then moving to the other side and beginning where I left off in the middle of the top, continuing on across the top and down the other side. No problem with either orange peel or dry spray. I was using my spot gun because the size didn't warrant setting up my full sized gun with pressure pot. Actually that sequence is not much different from doing a car - top down - for instance the roof first, then the hood and trunk, then on to the sides. Inevitably, in doing the sides after the hood, around the fender areas, there will be some "overspray" get onto the previous painted hood areas at a less-than-perfect angle that puts the gun-to-surface distance a little more than desired. The extent of that would be greater with larger fan patterns. I just haven't had a problem in doing it that way, even with a 14"-15" large pattern on a VW beetle. I suppose one could start the hood by doing a full pass down the top side on the fenders, then up and over to the center of the hood and repeating on the other side - then go back and finish the lower portions of the fenders. In other words, ending in the middle top of the hood rather than starting there. I have never tried it that way.

It would seem to me that no matter how you approach it, transitioning from a vertical surface to an attached horizontal surface (or vice-versa) will result in half the pattern falling on a just painted surface at an angle that is not perfectly perpendicular and therefore a little farther away than "normal".

Another thing I read about not long ago was the recommendation to use a greater than normal overlap for HVLP, in addition to a closer gun-to-surface distance and a slower travel speed. More like 70% (?) than the standard 50% overlap. I have 50% engrained in my thinking and simply continue it with my spot HVLP with no noticeable problem although I do try to get a little closer and travel slower than I am otherwise used to.

My guess is when you go down from a 1.5 tip to a 1.3 tip you will decrease the paint flow rate, assuming the same paint viscosity. I don't think the pattern size will change automatically unless you choke down on the fan control knob. To keep the same application rate with the smaller tip and w/o changing the fan control, you might try slowing down your travel speed a little to see if that helps. You could also try cutting back a bit on the air pressure at the gun (say 5psi), especially with the smaller tip, since less paint per minute means less required air per minute to atomize. If you haven't already done so, you might want to check your atomization and pattern shape by rapidly triggering the gun on and off for just a fraction of a second on a piece of cardboard just to verify a smooth, uniform pattern that does not take on an hourglass shape. I can't think of anything else to suggest.

Follow Ups:

• Re: Question about Orange Peel CNKS 17:20:33 07/27/05 (3)
  • Re: Question about Orange Peel Rod (NH) 19:18:20 07/27/05 (2)
    • Re: Question about Orange Peel CNKS 20:05:13 07/27/05 (1)
      • Re: Question about Orange Peel Rustyj14 15:47:15 08/18/05 (0)

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