Textural Problems

[theperfectstorm]

Lads:

  I am in the middle of painting a pair of cases.  I sanded both, primed twice, wet sanded the primer twice, painted once and wet sanded (with 400) the color once.  Problem is I still have a very uneven finish. In some places it is brighter than others, in some places it is almost flat.  So far, it has a rather disconcerting tiger stripe effect.

Quesiton is:

1)  Is this simply a matter of continuing to add coats until it evens out.
or
2)  Is there a larger problem on the metal that continuing to slop paint over won't address.

(Standard ATX cases, Dura-Cote Sandable Primer, Dura-Color Truck Paint.)

Any help appreciated.
Thanks

[Rob]

Welcome to the boards.

It's always a tough call without a pic to go by, but I'm thinking this is an application problem.

You didn't say much about your spray technique or pattern, but if you were incionsistent in the amount of paint you lay down across a pael, I could see the result becoming what you describe.

The "proper" technique is to keep your workpiece close to horizontal, and move your hand from side to side evenly, depressing the nozzle before you get tot he edge of the piece, and releasing it after. Make your passes so that the pattern only overlaps minimally, and don't lay down too much at once. This pic shows one pass as described above:



The piece is just sort of lightly dusted. Five or six repeats of this will get you a smooth, consistent texture. If you see a glossy, "wet" look you may be laying down too much paint (byhaving your nozzle too close to the workpiece).


But I also read that you have wet sanded--are you suggesting the stripes are there after wet sanding? I would expect no texture to remain.

[theperfectstorm]

This is the ironic heart of the problem.  I did indeed wet sand and the finish was very smooth.  After painting, the glossy areas are quite smooth.  But there are slightly rougher, flater patches among the glossy ones.  You can run your hand along the panel and feel where one surface changes to another and back as it runs from glossy to flat.

Very Confusing. 

[merlinicorpus]

You aren't waiting long enough between coats.  The "tiger stripe" thing usually happens when parts of the previous coat aren't completly cured.  If the previous coat isn't cured before you apply the next one, the paint will more or less curdle and have a texture of sorts.  Try waiting 24 hours or more between coats.  Also, the ambient humidty should be below 50% and a tempature of at least 60F at all times.

[GreyDeath]

Here is a helping Idea that Autobody speroot beerts use when they are Hand Roughing a body pannel Out Prior to Painting and is also applicable here in the Case Modding and paint Section

After you get your Sandable primer applied and before you start Sanding

Say you have a Grey pannel that you are gonna Sand

take A Can of red Sandable primer or Black Sandable primer and minst On a light coat of that Color,
the reason for doing this is

1. it Is to be Used as a guide after it has dried and when you start sanding Sand only as far as you need to ....In oirder to remove the red or black primer, when you have removed the red or Black primer you Know you have Sanded Enough

And 2

it prevents you from oversanding and thinning your Sandable primer Down