Paint Question
Thread Starter
Racer
Joined: May 2008
Posts: 271
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From: N.Y
Paint Question
i have started to sand my corvette(81) and almost done but noticed the fiberglass sometimes turns black and water leaves spots. i know it collects contaminents and soaks up water. i have it covered because it will take me a few more days to get it done. some water spots sand down but the outline is still there and i cant sand anymore or there will be a gouge, but the black streaks are solely on top and sand off. will it be ok to paint over all of this when i shoot primer if i use the oil wipes properly. any suggestions. 
also shooting 3 coats primer and then sanding it then 3 coats black and 3 coats clear, any tips or suggestions would be great, thanks
also shooting 3 coats primer and then sanding it then 3 coats black and 3 coats clear, any tips or suggestions would be great, thanks
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
i have started to sand my corvette(81) and almost done but noticed the fiberglass sometimes turns black and water leaves spots. i know it collects contaminents and soaks up water. i have it covered because it will take me a few more days to get it done. some water spots sand down but the outline is still there and i cant sand anymore or there will be a gouge, but the black streaks are solely on top and sand off. will it be ok to paint over all of this when i shoot primer if i use the oil wipes properly. any suggestions. also shooting 3 coats primer and then sanding it then 3 coats black and 3 coats clear, any tips or suggestions would be great, thanks
also shooting 3 coats primer and then sanding it then 3 coats black and 3 coats clear, any tips or suggestions would be great, thanksFiberglass does not turn black if it has been completely stripped of paint and primer/sealer.
It should not water spot if it is dry sanded....or if it is water sanded..and done out in direct sunlight...you could get water spots due to the water drying fast due to surface temperatures....and leaving behind a residue.
You should not gouge the panel if proper sanding techniques are being used.
I do not know where to go with this because I really do not understand what you have done or how you did it.
Are you dry sanding it and with what grit?
Are you water sanding it and with what grit?
Is there paint on the car or is it stripped? Partially or completely?
Is the car outside being covered with plastic? If so...and condensation is occurring...this can be a problem that you need to do something about.
I want to aid you...but I can not until I know what is going on and what actually has been done.
"DUB"
Thread Starter
Racer
Joined: May 2008
Posts: 271
Likes: 0
From: N.Y
I am sorry...but I have read this several times and I do not understand any of it. It is like a "Jeopardy" puzzle with many missing pieces.
Fiberglass does not turn black if it has been completely stripped of paint and primer/sealer.
It should not water spot if it is dry sanded....or if it is water sanded..and done out in direct sunlight...you could get water spots due to the water drying fast due to surface temperatures....and leaving behind a residue.
You should not gouge the panel if proper sanding techniques are being used.
I do not know where to go with this because I really do not understand what you have done or how you did it.
Are you dry sanding it and with what grit?
Are you water sanding it and with what grit?
Is there paint on the car or is it stripped? Partially or completely?
Is the car outside being covered with plastic? If so...and condensation is occurring...this can be a problem that you need to do something about.
I want to aid you...but I can not until I know what is going on and what actually has been done.
"DUB"
Fiberglass does not turn black if it has been completely stripped of paint and primer/sealer.
It should not water spot if it is dry sanded....or if it is water sanded..and done out in direct sunlight...you could get water spots due to the water drying fast due to surface temperatures....and leaving behind a residue.
You should not gouge the panel if proper sanding techniques are being used.
I do not know where to go with this because I really do not understand what you have done or how you did it.
Are you dry sanding it and with what grit?
Are you water sanding it and with what grit?
Is there paint on the car or is it stripped? Partially or completely?
Is the car outside being covered with plastic? If so...and condensation is occurring...this can be a problem that you need to do something about.
I want to aid you...but I can not until I know what is going on and what actually has been done.
"DUB"
o.k when it sits for a couple of days it gets a black residue kind of tint on some spots but it sand off without problem but some spots where rain or water is dripped on it do leave water marks and i am at bare fiberglass. i have been sanding it with an orbital sander with 80 grit paper and it is taking forever, there is like 6 layers to go through. and i do not have a garage so thats why i asked what to do with it, i can tarp it or is there other options? i should be done with it next week but it is raining here like every day, and then after this is all settled i am on to the 3 coats of primer then 3 base and 3 clear
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
o.k when it sits for a couple of days it gets a black residue kind of tint on some spots but it sand off without problem but some spots where rain or water is dripped on it do leave water marks and i am at bare fiberglass. i have been sanding it with an orbital sander with 80 grit paper and it is taking forever, there is like 6 layers to go through. and i do not have a garage so thats why i asked what to do with it, i can tarp it or is there other options? i should be done with it next week but it is raining here like every day, and then after this is all settled i am on to the 3 coats of primer then 3 base and 3 clear
Thanks for filling in the missing pieces I needed to try to help you.
Doing your body work outside and allowing it to get rained on is a BIG PROBLEM. At all COSTS...you need to find a place to get it out of the weather. Because if you don't....you are inviting DISASTER. OR...at least the ability for "MURPHY" to come a knocking.
Constantly allowing the body to get wet is allowing other containments to get introduced into the structure of your fiberglass body (so-to-speak) is NOT GOOD. Because you will have to allow the body to dry out BEFORE you prime it. AND if it is out in the weather (even getting dew on it) is NOT GOOD. The black spots you are experiencing may be soot, car exhaust, pollution, residue from sanding and anything else that you might think of that could leave a black spot. I am afraid in recommending that you apply a tarp. It REALLY needs to get out of the weather.
"DUB"
