Problems with tiger striping my metallic base

R

Radius

Hi Guys..

I am having big problems with tiger stripes on my metallic base. I am a total newb, so hopefully you guys can steer me in the right direction.

Paint is Dupont Chromabase in gray metallic - factory 04 Mazda 6 "Steel gray" color mixed 1:1 with basemaker 7160S with 1/2 ounce of ChromaPremier 12305S activator per pint per the datasheet.
Gun is a "green" Grizzly with a 1.4 tip
Air pressure is 30psi at the gun while spraying - 35psi when not spraying
Fan is almost full out
Fluid is approx 3/4 out?
Tip is about 6" away

I think the main problems are the gun and my technique. I am doing both the tailgate and the hood. The tailgate seems to turn out pretty good - no blotchy spots, tiger stripes, etc. The hood on the other hand is terrible. Lots of blotchy spots, tiger stripes, etc. I think part of the problem is that it is a lot easier to maintain a consistent motion and distance on the tailgate versus the hood.

It doesn't seem to matter if I stand in front of the car and go left to right, then back to left on the next pass, or if I stand on one side and start in the center. It's a reach for me to spray the parts farthest away, plus I'm in my gf's garage and it's a bit cramped. I wish I had more room to move around but I don't.

I'm trying to maintain a minimum of 50% overlap.

I've been told that I'm probably putting the base on too "wet" (thick?) and that's probably causing the tiger stripes.

Do I need more overlap?

Do I need to move faster? Maybe reduce the fluid?

I've also read that over reducing the base can help too. If I should over reduce it, how much extra basemaker should I use per pint?

Do I need a better gun? I don't have the money for a nice Iwata or SATA, but I have heard that the Devilbliss guns are ok. And I found this: Sharpe Razor HVLP for Metallic. Any idea on that one?

Here's the link: http://www.sharpe.com/sharpe/sharpe.nsf/Page/RAZOR+HVLP+for+Metallic

I don't mind buying a better quality gun if I can get it soon enough. It would be really nice if the gun could do both base and clear.

Anyways, any help is greatly appreciated.

Thanks,
Michael
 
Keeping the gun perpendicular to the surface and a consistent distance from the metal is just as critical as the overlap.
If when reaching toward the center of the hood you are tipping the gun so the portion of the fan nearest you is closer to the metal it will produce a dry spray on the opposite end.
Spraying it on too heavy will cause problems as well. Better to go with medium light coats and apply them in a smooth and consistent manner.

Obviously the gun makes a difference or we would all be using $19.95 models. The DeVilbiss Plus guns have a good reputation and whatever you buy make sure you have a compressor that puts out enough CFM to run the gun.
 
Looks like your using the fastest temp Basemaker. I've had similar problems in the past with silver and since then I always spray metallic base with ~85* reducer. Like 7185S. Even if the temps are in the 60* range. Just give yourself more flash time between coats.
 
Try backing off your distance a few inches and don't put it on as wet.
 
Not familiar with your gun but a couple of things stand out to me. 1. 1.4 tip is propably on the large size for basecoat. Most companies want you to use a 1.3 some even a 1.2 depending on the basecoat. 2. Basecoat is not meant to be applied heavy more product on the job does not mean better protection. Basecoat is colour only no protection value to speak of. 3. Rather than 50% overlap I would suggest 70 -75 % overlap tight to the panel & speed up a bit. When you are to far away from the panel & moving slow you tend to apply to much product & gun control is harder. When you move at a consistant speed it is much easier to be accurate. Pay attention to your guns air cap when spraying making sure you are perpindicular to the surface. Spraying somewhere on the masking paper before the vehicle will also show you if the guns pattern is even. If it is heavy on one end vs the other you have a problem or skinny in the middle & wider on the ends etc. Make sure your air pressure is accurate with the trigger fully pulled if it is to high or low this can also affect your issues. Adjusting the amount of fliud coming out of the gun as well can help. Turn you fluid all the way in then back it out 2 turns. Start there then you can take it out more or less as you wish to dial it in to your spraying technique.

Rob
 
7160 is too fast unless you're spraying in the cold, use 7175 or slower if your temps are decent. A slower reducer will allow you to put on thin coats and end up with uniform coverage and a better overall cure. Right now with the 7160 you're putting it on too thick.
 
There's alot of different things that can cause it and I see a couple things right off the bat with the chromabase. Any time you have a color such as a silver or gold and doing a larger area such as a hood 7160 is way to fast. I like going slow 7185s, but 7175s min that gives time for the flake to layout. Make sure you give time for the flake to do its thing and completely flash before putting on the next coat. Also try backing up to about 8in spraying with a 75% overlap. You want a nice closed coat, not super wet and not dry looking. Another little trick is once you have everything covered, wait until the base is still a little tacky and not completely flashed turn your air pressure down 20% at about 10 in. and do a coat with 75% overlap. Also with chromabase it's already pretty thin so over thinning it probably won't help. Also when you start work toward the middle of the hood then go around and pick it back up so your keeping everything wet.

If you put on dry coats it will look like crap, once your base flashes it should be as smooth as a babies behind. Also your clear will follow that and will usually be extremely pealy.

Like Rob said check your pattern on some masking paper, most of your cheaper guns won't operate well with a wide open pattern.
 
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