Question for the paint guys

[Stevie G]

Spraying Martin Senour Base/Clear coat.
The color is Bronze mist poly and appears uniform, however, there are what looks like overspray stripes if you look at it just right. I'm clearcoating tomorrow and have a few questions about the need to Color sand prior to Clearcoat. If the paint is smooth, Do I need to sand before clearing?
The literature at NAPA isn't that clear. All it says is to scuff the basecoat if it's more than seven days before clear coating. Also says I can clear fifteen minutes after spraying the base coat. So.....what's the answer?
To sand or not to sand, that is the question.
Thanks!!
Stevie G

[customcarpainter]

If I were doing it,I'd scuff the surface with 600-800 grit,tack it off,then shoot one more coat of the base.Over reduce and spray a coat with an overlap of about 60-75% moving your gun slightly slower and back it off from the surface to about 15-18".This should eliminate any stripes.

[Stevie G]

I'll give that a try on my test panel (Read that-Metal shelf)and see how that comes out. Most of the car came out okay, the hood and trunk lid are kicking my but.
Thanks for the response.

[Stevie G]

Since reduction is 2:1, how much should I reduce/over-reduce it?

[earl schieb]

2 base to 1 reducer? (wow, that sounds like some real low-solids stuff http://www.jalopyjournal.com/ubbthreads/images/graemlins/shocked.gif)
Considering today's weather, are you using the correct temp range reducer? Go up a notch(slower drying reducer)instead of over-reducing and try what customcarpainter suggested---heavy overlap, 15-18 inches away--maybe even a few pounds more air pressure or lower the fluid volume. Mist it on (but not TOO dry-spray)and let the reducer do the work.
Just don't EVER sand a metallic base before you clear it without recoating it with more color(but you know that, right? http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif).
Good luck, amigo.

[Stevie G]

I've been thinking about the reducer. I'm using a medium-slow reducer and a turbine HVLP rig (It's portable). I probably could go up one temperature range.

Thanks again.

[overspray]

It's going to be hard to get the metallic even with the turbine rig. Also with HVLP (especially in warm weather) use slower base reducer. HVLP spraying almost always should be 1 grade of reducer slower than a conventional spray gun for the same air temperature. If you sand the metallic base prior to clearcoat, the sanding scratches will show in the clear no matter how fine. The "7 day scuff" is so the clear can "bite" into the base because it sets up by that time. If you scuff or sand you MUST recoat the base. With the turbine rig try evening the metallic by Backing away about 15-18 inches and applying 2 coats-per panel- 1 panel at a time, changing spray direction for each coat. If you have coverage now try the "double coat" Diagonal one direction then reverse diagonal. Don't let the 2 coats be too dry or too wet. Also try to not stop your panel spraying exactly on the door/fender line for example. Move about 6-8 inches past or before the panel seam for the second pass to avoid "doubling up" on the seam line. By the second coat it should be somewhat wet. If you haven't used this HVLP much, its going to be tricky at best. overspray

[overspray]

Oh yeah- don't over reduce more than about 10-15%. Rely on the slower reducer. overspray

[Stevie G]

THANKS.
Looks like i'll take today off and pick up the slower reducer in the morning.

[Stevie G]

Okay,
The slower reducer helped.
I also noticed that I was "Drooping" the gun / Not holding it level. Once I fixed that, things came out pretty good.
It's all shiney now.
Woo Hoo!!
I thanked Dad for letting me practice on his car.
Three more repaints and every freakin one is metallic.
Anyways....Thanks for the help.