[msc66]

The pin heads at the convertible top shop chipped the paint off the edge of my door now I have to fix it (don't ask). Anyhow, I sanded it out and have been brushing the primer on to keep it contained to the damaged area. My question concerns the application of paint.

The paint is bc/cc and is my 1st experience with it (I painted the car but haven't done any blending with it). For a repair this small how far out do I need to blend this? Also what type of gun should I use? Should I just use the same hvlp gun I used to paint the car or maybe a jamb gun since its a small area? Also, what air pressure should I use?

After I blend the base coat, how far would you take the clear? Should I clear the whole door or just to a body line. When I was spraying laquer I could back roll the tape at a body line and sand and buff the edge out. Can you do this with this clear?

Any help would be greatly appreciated.

[baddbob]

You'll want to remove the door handle, if you're not familiar with doing a urethane clearcoat blend then I would definately clear the whole panel. Blending out the basecoat will be similar to what you did with lacquer years ago. A touchup gun will work better than a full size gun for that small area-and pressure will depend on gun model. Blending urethane clear isn't really difficult but I'd definately suggest you practice on something else first or just clear the whole panel. Do you have any left over paint from when the car was painted last?

[msc66]

Yeah, the door handle will definately come off and yes I have a little paint left.

I've read numerous threads on this and have gotten differing opinions on what grit paper to sand with. What should I sand the area to be color coated and what should I sand the area just to be cleared? Also, should I use any sort of adhesion promoter? For the bc or for the clear?

Thanks for the quick response!

[baddbob]

I use 600 or 800 to prep for the color and prep out farther with 2000-2500 for the clearcoat blend, No adhesion promoter necessary. You will need some blending solvent to melt the dry edge of clear. Let the repair cure up really well (some time in the sun would be best) before any buffing.

[duallybuster]

If it came into my shop this is the procedure that I'd use. Since the paint is in great condition, I'd DA 6 to 8 inchs past the repair area with 400. BC/CC like 400 for some reason. Then DA the rest of the door fwith 600 wet. I'd first shoot a spray disc out to see how many coats its going to take to hide the repair area. The spray disc's we use has a clear side built in. Saves a ton of material and time. I'd start with just light coats just on the repair area to get the primer hidden. Once I've got it close to hidden, I'd then start my blend paying close attention to the spray disc that I made. Since 8oz of color (mixed 1:1 = 16oz) will be more than enough material for a whole door, I would blend about 1/2 the door or more depending on my mood. I'd reclear the whole door. When blending I usually keep the guns psi the same (SATA JET 2000 = 2 bars). I control the blend with the trigger, distance and the speed that I'm shoot.

Don't try blending the clear coat, your asking for trouble down the road.

[msc66]

Thanks guys,
See what I mean, 2 guys 2 different preferences on sand paper. Just out of curiosity, any theories on why one grit paper over the other?

[duallybuster]

Experience.
Give you a little example. I had this yahoo come in the shop the other week and wanted me to spray his car. He said that he had done all the bodywork and prep work him self and just wanted me to shoot it. I walked out to see what I was getting myself into. I couldn't help but laugh. The filler was wet sanded with 600. (You never wet sand filler, and the finest grit you want to use on filler is either 220 or 320) He didn't know how to feather edge. He would have had buttholes all over the car. I ran my hand down the side and I could feel the waves. He wet sanded the entire car with 600 which was OK, but it was done by hand with a block. Now your going to ask what's wrong with that, First off, it's going to be a over all paint job, and it's black. Body has to be close to perfect for black. 2nd if he would have read a Cromabase P sheet, it tells you that 400 is the finest grit for base. Now this is where experience comes in. Blocking with 400 or 600 is a mistake. Why you might ask, because you will see the sand scratches. (remember it's going to be black) Now let say this is going to be a show car, if you blocked the primer with 320 first to get it flat followed with the DA and 400, then you have no sand scratches. You know how people say that prep is 90% of the work for a good paint job, what do you think they area talking about, it just isn't wax and grease remover, it everything up to the time you shoot on that first coat of color.

[msc66]

OK, tell me I'm being a freak here but the blend looked ok but now that the clear's on the door looks darker. Please tell me its just cause its fresh and that once its cut & buffed it'll look the same.

BTW, I found a ding in the door so I decided to fix that too so I ended up blending about halfway out the door.

[46chevyfleetline]

Well to me it's just the lighting. To me it looks okie dokie.
Get it out in the sun and it will tell ya straight away.

[Rambo_The_Dog]

Originally Posted by msc66

OK, tell me I'm being a freak here but the blend looked ok but now that the clear's on the door looks darker. Please tell me its just cause its fresh and that once its cut & buffed it'll look the same.

BTW, I found a ding in the door so I decided to fix that too so I ended up blending about halfway out the door.

From the picture it doesn't look too bad - that's a tough color to paint and get to look right.

I'd say if it looks darker outside it's because you blended out on the door farther.

Did you blend onto the quarter of just to the door edge?

[msc66]

I didn't blend onto the quarter. I started at the door edge and went about half way up the door. Then cleared the whole door. Odd thing is that it the door and front fender that looks off but I didn't blend to the front of the door.

[baddbob]

Some clears have a yellowness to them and will show big differences on lighter colors, did you use the same clear as what's on the car? If you look at the clear in a clear mixing cup does it look completely clear or does it have a yellowish to it?

[jcclark]

Ditto to the above.
Some clears aren't clear, also maybe the original wasn't as clear as your
new clear? Who knows.
Sometimes buffing out the adjascent panels help.
Yours looks good but maybe a good polishing will get them to look
closer to the door. Try that first.
If that doesn't work, try sanding/buffing the door.
Sometimes the buffing out will slightly help match the color.
You can buff to a good shine and still not have the clear as clear
as after first sprayed. And though you can't see the difference,
when it's against another panel it looks different, usually lighter.
It's just enough to make that small difference in clarity which
changes the shade slightly.

[msc66]

OK, now that I've sanded and buffed the door it matches the quarter perfectly but not the front fender. Odd. Maybe when I painted the car I stopped to refill the cup at the fender and door creating a difference. I can see a texture to the basecoat in the front fender that I don't see in the rear quarter.

Regardless, I only have a little paint left so the only option I have now is to blend the fender and door at the seem and clear the fender and door again. Hopefully I won't screw that up as this is the last time. I'm going to have to live with it this time.

As for the clear, I don't think its the same gallon but its the same clear (dupont 7500s).

While we're on the subject of clear. Since I'm painting in less than ideal conditions, would it hurt to use the next lowest temp activator than recommended to help it set up faster to keep the trash out? That's also what I happen to have.

[duallybuster]

Use the lowest hardner you can get away with, it will stay wetter longer and level out smoother. As far as trash getting into it, make sure everything is clean before you shoot. water down your floor, the walls, hose, everything. Most dust comes from the painter, so get you a paint suit, but I've also seen alot of trash coming from what we call clear dust.(overspray hitting the car when its drying to quickly because of fast hardner). Thats the only problem with using faster hardner in clear. Now for the base, I'd use it so I can put on the clear quicker.