Drop coats?

J

jeremyb

Am I just being dumb to think there should be no reason why you are drop coating your basecoats? Seems to me, from seeing others advice on the subject...that it is an ok "technique" and that if you have to drop coat, that doesn't make the basecoat system you are using inferior or your spraying technique wrong :rolleyes:

Setting waterborne systems aside, I see no reason to be drop coating your base. With proper gun adjustment, spraying technique, reducer selection, and quality base system....you shouldn't need it to get your metallic to lay evenly. It seems that others have ok'd the technique lately...to me that just condones poor spraying techniqe, using lower quality materials and spraying equipment.

If I EVER have to drop coat anything, it is becuase I have messed up in adjusting my gun or spraying. Even in tech sheets it tells you how to drop coat. I could see it being used in collision...to match whatever it is you are repairing, but that's about it.

Is it just me or what?
 
I don't drop coat anything (drop the gun, tip set, spill paint, etc. LOL) and have not found it necessary to date. The last metallic job I sprayed the car in pieces and then assembled it with no issues on color matching and no drop coats required.
My understanding is that the manufacturers redesigned the flakes (maybe someone can verify this?) so that orientation is not the issue it was in years gone by. Seems guys get in trouble today when they shoot their base too heavy or don't wait long enough between coats.
 
Some guys drop coat to minimize fish eyes.
If everything is right, you don't need it.
But when there's a problem, and a few fish eyes appear,
a drop coat seems to be a solution, even on the second spraying.
I've tried it both ways many times and haven't noticed any difference
in the final finish. I think it's a moot point.
 
I have found that even with lower quality bases if I activate and use a quality reducer I generally don't have a problem. Along with gun setup, using as slow a reducer as you can will generally give the metallic enough time to orient before flashing off.
 
One thing for sure, if a drop coat is done it should be done while the basecoat is still wet, drop coating each panel as you go, immediately after a normal coat. Using a slower reducer is helpful for this too.

I prefer to not drop coat, but every so often I do, depending on how I feel the job is looking.

Paint jobbers will have us believe that is is ALWAYS application error, but I tend to believe there are certain mixtures in nearly every paint line that are more susceptible to striping/mottling. Combine one of these mixes with a gun or painter that is having a bad day, and you have a problem.
 
crashtech;14548 said:
One thing for sure, if a drop coat is done it should be done while the basecoat is still wet, drop coating each panel as you go, immediately after a normal coat. Using a slower reducer is helpful for this too.

I prefer to not drop coat, but every so often I do, depending on how I feel the job is looking.

Paint jobbers will have us believe that is is ALWAYS application error, but I tend to believe there are certain mixtures in nearly every paint line that are more susceptible to striping/mottling. Combine one of these mixes with a gun or painter that is having a bad day, and you have a problem.
Click to expand...

Some MS tech sheets say to drop coat.
 
Panelwagon62;14544 said:
Doesn't drop coating also contribute to less adhesion?
Click to expand...
It can but how dry is your blend area when blowing base........it can get dry on the outside edges.
 
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