Autobody technique question?

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4765982

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Hello. I was wondering about how autobody shops repair very small paint problems within

large body panels. For example, if you have a paint problem where the paint has been damaged right down to the metal, say the size of a quarter, within a fender does the entire panel have to be repainted and recleared? Is it possible to just repaint the very small area that is damaged blending the paint into the surrouding area and also doing the same with the clear? I have concrens with having a shop repainting and entire panel just to fix a very small problem and having problems making the paint match the other panels perfectly without blending into the rest of the car. I am just wondering what is the best way to repair this so that it can never be detected. It is a 2002 Jetta RED not metallic that is in completely perfect shape, except for a minor problem. Please advise me! Thanks.
 
You can get some very expert advice on this (in addition to the same here) over at the forums at the AutoBody Store but I'll give you my take on it from someone who does it as a hobby.



In order to maintain the factory paint warranty each paint manufactuer has a guidelines for using their products (what to mix it with, the ratio's, how to dry it and for how long, that sort of thing). This is important cause the bodyshop that does the work (esp at the dealership) has to restore the paint job to the original factory warranty spec.



Another thing that is always listed is that the Clear Coat must be applied edge to edge. This is because Clear Coat will not usually "blend" and not only can you end up with a clearly visable line from where the new clear stopped and the old clear was, but the clear coat could start to fail at that point.



You can pull the Tech sheets and read it for yourself. The base coat can be blended into the old coat though.



Now having said these things there are some variables. For instance those tech sheets say if the paint technician does not want to lay the Clear Coat down edge to edge he can follow the paint manufactuer's "blending" procedure using the recommended "blending agent".



From my own experience, it is much harder to blend the clear right and takes more prep and masking work than it would to just re-clear the whole panel. If you get it wrong you will have to wait for the Clear to dry enough to sand the panel down and try again.



Think of it this way, which would be easier, to make a quarter sized area look like the rest of a panel or to just make the whole panel look the same.



The other variable is that insurance compaines are starting to press body shops into doing more blends cause they feel it would be cheaper (and insurance companies are all about being cheap).



To that end a few paint manufactuers are creating procedures to do spot repairs with their products, areas about the size your talking about and no greater.



Portable Dent Repair (PDR) service is like this. You'll see them at dealerships sometimes doing spot work on cars (painting right there outside).
 
Thank you for the response. Ok, so refinishing the entire panel is probably the best way to go. I have always questioned those repairs where they just blend into the surrounding paint. So if they are refinishing the entire panel what is the best technique that will ensure that the paint and the clear will match the rest of car the perfectly. Do they need to blend into the rest of the car? Also, is a non metallic red easy to match. There is no fade on this paint. Do you think that they should be spraying "test" panels to get the perfect match. How do you think this should be done properly? This is a good education on how this is done. Thanks.
 
First and for most the quality of the shop and the experience of the technicians (body and paint) will determine the outcome of any paint job. So do your homework and get references before committing. Ask the shop to look at some recent work they've done or ask friends/family where they went and if they were satisfied.



The "best" technique as you say for getting the repair paint job to match the existing paint will depend on a lot of variables.



There are really two colors of paint on any car. One is the color the paint was when it left the factory (this is the paint code found on the RPO label on the car) and the other is the color of the car now.



Paint will fade with time (oxidize) and if the paint hasn't been properly maintained over the years it's quite possible that the paint on the car will no longer match the original color.



So they should start with determining which color they are going to use. Bodyshops as well as Autobody Paint Suppliers have a niffty little camera that they can place on the panel and it takes a snap shot. The device is then connected to a Computer in the shop which will tell them how to mix the paint to get the correct color to match the paint on the panels.



The other way is to use the color code off the RPO label. Again here's where the quality of the shop comes into play. An experienced painter can look at the paint on a outside panel and the paint on let's say a door jamb and determine which method will provide the best match. If the car is relatively new and as you say no fading they'll probaly go with the RPO label.



Metallic's and Pearl Coats are very hard to match. Think of it this way. Put a piece of white paper on the ground and pick up some sand and throw it into the air so some lands on the paper. Now get another piece of paper and try that again and see if the sand pattern (the way the sand landed on the paper matches). Keep doing that as many times as needed to convince yourself that it's almost impossible.



Metallic paints are no different. The metallic effect is produced by "flakes" in the paint. The way the air was blowing in the both, how fast the gun was moving, what angle the gun was relative to the panel, all these things make it very difficult to get a good blend. Not impossible, just difficult when dealing with metallics.



They will most likely have to blend into adjacent panels in order to make the repair "dissapear" into the rest of the car. Again this is all part of a standard paint procedure and if the shop/painter is worth their salt (and your money) they will know how to handle this.



Same goes for a "spray-out" of the spraying of test panels.



What a lot of people don't realize is autobody and paint work is not the same as mechanical work. The latter is just parts, take one out and put another in. Maybe move some stuff out of your way but that's it.



The former involves processes that take time to perform. If any part isn't done right, you have to knock the finish down (how far will depend on what went wrong) and start over.



Add this to the fact that most paint booths run on commerical power (3 phase 208V or 230V) for ventilation and curing) as does the air compressors need to run the air tools and all and the shop owner has some siginificant utility costs. Doing things over loses them money which is why the focus is getting it right the first time and you'll see and overall reluctance to re-do anything.
 
I am planing on telling them to do whatever it takes to make it perfect. I don't expect them to work off a quote on this job but to tell them to just "do it by the hour". I know that some people just don't seem to care to much about how things match, you know what I mean. Those kind of people may see cars as basic transportation. I am planing on taking it to a very high end shop. I don't what to tell them how to do their job, what should I say to them as far as they should take this. I don't want them to repaint the entire car trying to match everything perfectly.
 
Going to a high end "custom" shop is always better than the run of the mill production ones.



The latter do mostly insurance work and want every thing in and out. while the former will take the time needed to get things right.



There isn't any need to them to paint all of the car to get the blend right, they'll just extend the paint process into the adjacent panels (those panels next to the one where the repair is). For a fender they may go into the door, hood and bumper.



Here's how I would approach it. I go in and ask for and estimate. They come out and look at the car and give me a price. If the subject hasn't been proached already I ask "won't you have to blend the repair into the existing paint job". Once they say yes, I tell them I'm expecting that to be seemless, that is under any light I don't want to see the difference in the color of paint new and old. Then ask what's that going to take?



Again if your going to a high-end shop they should already know not only how to do this but it's expected.



If it takes them ten minutes or ten years that's not your probelm. They should have the kind of staff that can do this type of work.
 
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