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How to Repaint Cowling?

WJaviation

Active Member
How did yall prepare your cowlings to repaint?

Did you sand down to bare fiberglass or just scuff and paint over the factory job?
 
Depends.

Why are you repainting? If the paint is coming loose, you have to sand it all off and start with a fresh surface.

If you're touching it up and don't mind extra weight, you need to rough it up with the appropriate (say 400 grit) abrasive, prime, and repaint.
 
How did yall prepare your cowlings to repaint?

Did you sand down to bare fiberglass or just scuff and paint over the factory job?

If it's factory, call and ask what paints were used. Then call the paint manufacturer and ask about repainting.
If the paint job isn't flaking off, I would wet sand the finish coat paint down to primer. Minimize weight gain. Then shoot new top coat.
 
If it's factory, call and ask what paints were used. Then call the paint manufacturer and ask about repainting.
If the paint job isn't flaking off, I would wet sand the finish coat paint down to primer. Minimize weight gain. Then shoot new top coat.


Its the factory painted (grey) cowling and fairings for the RV12iS. I just wanted to repaint a new color.

Yeah I've started sanding and already I'm seeing a multitude of air bubbles , pinholes and crumbling micro filler spots. Seems like the paint was covering a lot of flaws. My OCD is making me want to go ahead and sand to fiberglass and rebuild it back up right.
 
If anything is flaking, you need to sand it back until it stops flaking. Now fill any pin holes in the sanded area and highbuild prime those areas. Check for pin holes again and reprime those areas. Now we are at the point that’s the same as if the cowl didn’t have any peeling spots. Sand the whole cowl with 320 grit on a DA sander. As for the paint you use, single stage urethane will easily cover 320 grit sanding marks. If using a base/clear system, your going need to sand with something around 600-800 grit.

Edit - OP, I didn’t see your last post. I was thinking of repairing a previously painted cowl. I see yours is new.

For a new cowl, sand the whole thing well with 180 grit on a DA. Once sanded, fill any obvious pin holes and voids with filler. Sand smooth with 180 grit and then high build prime. The primer will show you all the remaining pin holes. Fill those, sand with 320 grit and reprime. At this point you should be 99% pin hole free. Fill any remaining pin holes, and sand. DA with 320 grit if using single stage paint, 600 grit if base/clear. If hand sanding, 400 grit single stage, 800 grit base/clear. I hope this helps.
 
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Gel coat

Its the factory painted (grey) cowling and fairings for the RV12iS. I just wanted to repaint a new color.

Yeah I've started sanding and already I'm seeing a multitude of air bubbles , pinholes and crumbling micro filler spots. Seems like the paint was covering a lot of flaws. My OCD is making me want to go ahead and sand to fiberglass and rebuild it back up right.

That sounds like Vans gel coat. That exactly why it's applied. Some builders sand it off because it can crack.
 
That sounds like Vans gel coat. That exactly why it's applied. Some builders sand it off because it can crack.

Yeah I think I'm gonna try and sand it down and then micro all the flaw areas, then skim coat with West systems to seal it all in. Then sand the outer epoxy and paint.

Does that sound feasible or am I missing something?
 
I pained the cowl (and all the fiberglass parts) with Evercoat Featherfill on my RV10. I thinned a a bit and painted it on with a brush. When a saw pin holes a stabbed at them with the brush until they were filled. I did two coats then I blocked it down with 240 before it went to the paint shop. 2 years later and no fiberglass weave is showing.
 
Process

Yeah I think I'm gonna try and sand it down and then micro all the flaw areas, then skim coat with West systems to seal it all in. Then sand the outer epoxy and paint.

Does that sound feasible or am I missing something?

That's the standard method for finishing fiberglass.
Micro, cure
Block sand
2 coats epoxy neat, applied with brush or roller, 30 min apart, cure
Block sand till texture is flat.
2 coats Epoxy primer neat, applied with brush, 1 hour apart, cure (optional step)
Wet sand
Spray primer, cure
Wet sand
Spray paint
Cut& Buff
 
That's the standard method for finishing fiberglass.
Micro, cure
Block sand
2 coats epoxy neat, applied with brush or roller, 30 min apart, cure
Block sand till texture is flat.
2 coats Epoxy primer neat, applied with brush, 1 hour apart, cure (optional step)
Wet sand
Spray primer, cure
Wet sand
Spray paint
Cut& Buff

That's super helpful, thank you!
 
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