You guys have sent me like 20-30 emails asking me to put up a post on bodywork/painting in more detail, so here goes I'll try. I know the other post was hard to follow as I was trying to help Roadgrime and also trying to answer everyone questions along with it.
I figured with all the mail I better try to make all this clearer. This may take me 10 days or so to do, all I can do is a little at a time. I work too many hours.
First off, before you do anything you need to decide the condition of the origianl paint and if its been repainted, also what kind of bodywork/rust repair is needed. Do you want to keep the original color or do you want to color change it? Are you going to park the rig or still drive it? Do you really have the tools available to do this project? It takes a lot of tools, garage with nice neighbors, and a sizeable compressor to even get involved. There are some more questions you need to ask yourself, but this will get you started.
I'm going to start off with finding out the condition of the paint and if its been repainted. This will help you decide on stripping it or just repainting over the old paint.
I use a mill thickness guage to check paint thickness. The cheaper ones look like a ink pen. They have a magnet on one end. You stick the magnet on the vehicle and pull the outer portion of the guage slowly, watch the window, it will have numbers going to 20. Just when the magnet pulls off the surface, it shows the reading. You will want to do this several times and check the rig in like 10 different places to get an idea what your working with. A virgin/factory paint job will be in the 6-8 range....Anymore than that, and its been repainted unless its been striped. Most 2nd jobs will be in the 12-15 range and 3rd time jobs will be 18 or over.
You can also take a sander and feather edge a spot. This will reveal the coats in front of your eyes..You would want to do this is several spots, because the vehicle had maybe just been repainted in one area. You would see metal, ecoat primer, factory sealer, paint, then possibly clear coat all in layers. If its been repainted you will pretty much see this again on top of the factory paint. I have feathered spots on a few rigs that I counted as many as 15-16 or more layers...
Also a razor blade on a blade tool works too..Find a high body line or edge and cut the paint to the metal...You will also be able to count the layers.
Still for speed and reliability the paint thickness guage works best.
I generally plan on stripping if its been repainted even once. I never trust what the other guy done. Most of these rigs are now old enough that they will probably need stripped anyways to get a nice job..Most of these rigs have hazing/fading/dulling. Crazing(very small cracks in the paint) Peeling, or bad rock chips. Seperating or faded clear coat. Any of these items I just mentioned will require stripping to get a new long lasting paint job.
It is possible to use a thick coat of primer and then try to fill all the problems of the old paint, but then you will have a problem of brittlement. Thick paint has a brittle problem and it will chip and peel way easier then factory(and we all know how easy the factory paint chips)
If youve noticed over the years paint doent chip as easily as it used too. They used to use many coats and everyone still thinks the more paint, the better. That used to be a good quote, not anymore.
In the world of paint these days the less is better now. The paint is much harder now than it used to be and requires a final total coat mill thickness of 12-14 or less mills to be chip resistant. If you stay within these limits, a repaint can be just as chip resistant as the factory and many paint MFR's will put a lifetime warranty on the paint if your under the 12-14 mill thickness. A mill is very close to the same thickness as a cigarette cellophane wrapper.
Im going to go into stripping first, as 90% of us will require this.
I'll take a hood and go into that and tell you everything I do to a hood. For instance the hood on my 80 chero is single stage(no clear) enamel. It is still pretty shiney with no visable craking or crazing. Its in pretty good shape for 24 year old paint. I can see it was garaged for a portion of its life. It has some small dents and a few waves in the sheetmetal.
It has major chipping in the front. Its actually starting to surface rust in the very front. It has rock chips varying from alot to a little the further you go back on the hood. I would rather strip it that try to feather edge out all the rock chips. The rock chips need to be removed some way as not to see them thru the new paint. Anytime you are feather edgeing paint you will probably need primer in that area to get it straight again.
Think of a wood table with a scratch. If you sand out the scratch, then look accross it, you will generally see a low spot where you sanded the scratch. Feather edging paint is simaliar. You will need a very gradual feather not to see it when your done. That is why all but the very experienced will need to use primer to fill the low spot you just created.
Beacuse of all the chips, and the body waves and dents, I will strip it, and start a new foundation from bare steel up.
Well I'll get into more as I get time....For now, I'm out of that......Have a Great Night!!
Carey
I figured with all the mail I better try to make all this clearer. This may take me 10 days or so to do, all I can do is a little at a time. I work too many hours.
First off, before you do anything you need to decide the condition of the origianl paint and if its been repainted, also what kind of bodywork/rust repair is needed. Do you want to keep the original color or do you want to color change it? Are you going to park the rig or still drive it? Do you really have the tools available to do this project? It takes a lot of tools, garage with nice neighbors, and a sizeable compressor to even get involved. There are some more questions you need to ask yourself, but this will get you started.
I'm going to start off with finding out the condition of the paint and if its been repainted. This will help you decide on stripping it or just repainting over the old paint.
I use a mill thickness guage to check paint thickness. The cheaper ones look like a ink pen. They have a magnet on one end. You stick the magnet on the vehicle and pull the outer portion of the guage slowly, watch the window, it will have numbers going to 20. Just when the magnet pulls off the surface, it shows the reading. You will want to do this several times and check the rig in like 10 different places to get an idea what your working with. A virgin/factory paint job will be in the 6-8 range....Anymore than that, and its been repainted unless its been striped. Most 2nd jobs will be in the 12-15 range and 3rd time jobs will be 18 or over.
You can also take a sander and feather edge a spot. This will reveal the coats in front of your eyes..You would want to do this is several spots, because the vehicle had maybe just been repainted in one area. You would see metal, ecoat primer, factory sealer, paint, then possibly clear coat all in layers. If its been repainted you will pretty much see this again on top of the factory paint. I have feathered spots on a few rigs that I counted as many as 15-16 or more layers...
Also a razor blade on a blade tool works too..Find a high body line or edge and cut the paint to the metal...You will also be able to count the layers.
Still for speed and reliability the paint thickness guage works best.
I generally plan on stripping if its been repainted even once. I never trust what the other guy done. Most of these rigs are now old enough that they will probably need stripped anyways to get a nice job..Most of these rigs have hazing/fading/dulling. Crazing(very small cracks in the paint) Peeling, or bad rock chips. Seperating or faded clear coat. Any of these items I just mentioned will require stripping to get a new long lasting paint job.
It is possible to use a thick coat of primer and then try to fill all the problems of the old paint, but then you will have a problem of brittlement. Thick paint has a brittle problem and it will chip and peel way easier then factory(and we all know how easy the factory paint chips)
If youve noticed over the years paint doent chip as easily as it used too. They used to use many coats and everyone still thinks the more paint, the better. That used to be a good quote, not anymore.
In the world of paint these days the less is better now. The paint is much harder now than it used to be and requires a final total coat mill thickness of 12-14 or less mills to be chip resistant. If you stay within these limits, a repaint can be just as chip resistant as the factory and many paint MFR's will put a lifetime warranty on the paint if your under the 12-14 mill thickness. A mill is very close to the same thickness as a cigarette cellophane wrapper.
Im going to go into stripping first, as 90% of us will require this.
I'll take a hood and go into that and tell you everything I do to a hood. For instance the hood on my 80 chero is single stage(no clear) enamel. It is still pretty shiney with no visable craking or crazing. Its in pretty good shape for 24 year old paint. I can see it was garaged for a portion of its life. It has some small dents and a few waves in the sheetmetal.
It has major chipping in the front. Its actually starting to surface rust in the very front. It has rock chips varying from alot to a little the further you go back on the hood. I would rather strip it that try to feather edge out all the rock chips. The rock chips need to be removed some way as not to see them thru the new paint. Anytime you are feather edgeing paint you will probably need primer in that area to get it straight again.
Think of a wood table with a scratch. If you sand out the scratch, then look accross it, you will generally see a low spot where you sanded the scratch. Feather edging paint is simaliar. You will need a very gradual feather not to see it when your done. That is why all but the very experienced will need to use primer to fill the low spot you just created.
Beacuse of all the chips, and the body waves and dents, I will strip it, and start a new foundation from bare steel up.
Well I'll get into more as I get time....For now, I'm out of that......Have a Great Night!!
Carey
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