I wrote this letter to someone who had a paint failure. I am posting it to see if anyone had any comments about it or anything they would like to add. I am not an expert on painting, just some of my opinions and thoughts. Regards, Terry
The variables could be enormous. If they use too much resin in the pannels and they are not completely dry, that could cause problems from the resin curing over time. But, if your painter sanded (opened the pores up on the fiberglass) then washed the dust off with water and didn't let it sit in a hot/warm environment for a week or two before applying the gellcoat, I would likely blame it on that. I would call the manufacture of your pannels and ask for a recommendation on painting process. I am certain they would say not to use any water.
I also have the belief that original paint jobs (though not that pretty) had a lot of things going for them. The original paint was very thin. Two coats of primer, sanded lightly and two coats of laquer and any touch up that was needed. I heard the primer was laquer based and sort of ate itself into the fiberglass. Also, the paint was thin and I think more BREATHABLE. If vapor of some sort was starting to accumulate or get on the move in the pannel, it could get out because the paint was thin. But, laqure had its other problems of durability. These days, people tend to over restore the cars and try to make the paint flawless. Corvettes have uneven body pannels and waviness to them. To get that out, the painter has to put a ton of paint on the car (lots of chemicals). The thick paint acts as a barrier and is not as breathable. Water is another chemical that is taken for granted. If you wash the bear fiberglass off with water, you have to let it sit a long time in a warm environment to get that out. So you can see how long it could take to get through all the hoops to paint a car. I have heard of some people letting their cars sit a year before finishing the car. I think paint suppliers would recommend you put nothing on the bare fiberglass after sanding.
Bottom line is that fiberglass is terrible to paint. If it weren't they would have kept using it. I think gellcoat is better than no gellcoat. I think GM figured that out when they went to SMC pannels ( I believe they have a gell coat on them). That was there attempt to improve things. I think later they went to something totally different but I am not familiar with newer corvettes.
I think it is probably better to not think if you will have a problem with your paint but when you will have a problem with your paint. It is just the wrong surface to put paint on.
Also, moderate climate is good for the car. Direct sunlight is bad for the car once the paint is on it. The heat will put the chemicals on the move if they are in there.
I talk like an expert but I am not. I have never painted my own car. I have never had a car painted. I might have my 68 painted this summer. But I still have some work to do on it. I have read and talked to people about the subject though. If I had to sum it up I would say, once you start to sand the bare fiberglass you can't put any chemicals on the surface, keep bare hands off the surface, use line driers off of the aircompressor and use a filter at the end of the hose for blowing the car off, change the filter often, don't use oil in your air tools, take tons of time between each stage of painting the car, paint the car in a warm dry climate. Best regards, Terry
The variables could be enormous. If they use too much resin in the pannels and they are not completely dry, that could cause problems from the resin curing over time. But, if your painter sanded (opened the pores up on the fiberglass) then washed the dust off with water and didn't let it sit in a hot/warm environment for a week or two before applying the gellcoat, I would likely blame it on that. I would call the manufacture of your pannels and ask for a recommendation on painting process. I am certain they would say not to use any water.
I also have the belief that original paint jobs (though not that pretty) had a lot of things going for them. The original paint was very thin. Two coats of primer, sanded lightly and two coats of laquer and any touch up that was needed. I heard the primer was laquer based and sort of ate itself into the fiberglass. Also, the paint was thin and I think more BREATHABLE. If vapor of some sort was starting to accumulate or get on the move in the pannel, it could get out because the paint was thin. But, laqure had its other problems of durability. These days, people tend to over restore the cars and try to make the paint flawless. Corvettes have uneven body pannels and waviness to them. To get that out, the painter has to put a ton of paint on the car (lots of chemicals). The thick paint acts as a barrier and is not as breathable. Water is another chemical that is taken for granted. If you wash the bear fiberglass off with water, you have to let it sit a long time in a warm environment to get that out. So you can see how long it could take to get through all the hoops to paint a car. I have heard of some people letting their cars sit a year before finishing the car. I think paint suppliers would recommend you put nothing on the bare fiberglass after sanding.
Bottom line is that fiberglass is terrible to paint. If it weren't they would have kept using it. I think gellcoat is better than no gellcoat. I think GM figured that out when they went to SMC pannels ( I believe they have a gell coat on them). That was there attempt to improve things. I think later they went to something totally different but I am not familiar with newer corvettes.
I think it is probably better to not think if you will have a problem with your paint but when you will have a problem with your paint. It is just the wrong surface to put paint on.
Also, moderate climate is good for the car. Direct sunlight is bad for the car once the paint is on it. The heat will put the chemicals on the move if they are in there.
I talk like an expert but I am not. I have never painted my own car. I have never had a car painted. I might have my 68 painted this summer. But I still have some work to do on it. I have read and talked to people about the subject though. If I had to sum it up I would say, once you start to sand the bare fiberglass you can't put any chemicals on the surface, keep bare hands off the surface, use line driers off of the aircompressor and use a filter at the end of the hose for blowing the car off, change the filter often, don't use oil in your air tools, take tons of time between each stage of painting the car, paint the car in a warm dry climate. Best regards, Terry