Hi Dave, thanks for the kind words matey, this is based on work I have done so it may not be up to the levels of the professionals and took lots of trial and error and used aerosol paints to do the job. These jobs were done in the garden so I had to fight off bugs and insects from landing on the sticky paint as it dried
Anyhoo I'll try and explain what i did, here goes...
1. I washed the area using a small amount of shampoo to ensure there were no oily deposits/residue as I have found that this stops the primer from taking, rinsed and then left to dry.
2. With the area now clean I sanded down the area to get a roughish finish to get rid of any and all impurities in the body part/panel using a 400 grade of paper, dry at first for the heavier marks knocks etc and then used wet to fine tune the surface. The pressure applied was just enough to rub down and not create any unevenness in the surface, so gently does it.
2. Where there were holes and or scratches that were too deep to be rubbed down I used Isopon P38 filler to fill it these imperfections and tried to get a smooth flat finish and left to dry.
3. On these now filled sections I used 400 paper dry to get an almost flat finish and the used the same paper wet to finish to a level but not smooth surface.( Step 2 and 3 not required if it's a spray only).
4. With a the surface now smooth'ish I used a 1200 paper/wet to go over the whole area to match the once even areas with the now filled sections (where required) until its good enough to be able to let it take a primer coat or two.
5. I used a plastic based primer (as I was only spraying on plastics at that time - but standard primer should do for metal sections) to go over the entire surface area going in sweeping movement backwards and forwards until the area was covered. I left this to dry and then used a 1200 paper to smooth out any little bits that may have built up on the primer surface, very gently though as to not create any unevenness. With this then done another coat of primer to make sure all areas were completely covered. I had the can about 4 to 8 inches away to stop the stuff blowing away in the breeze
6. After getting hold of a good colour coded paint, I set about the parts in sweeping motions, but doing lots of thin layers to stop it running and to then only have to rub it down and restart. As the layers build up you begin to see the full colour begin to take shape, with 20 minute drying times between each coat. I found that once the colour had begin to come to life, adding more layers after that was of little use as the colour was there. Now as I found that as long as the primer finish which was rubbed down to a pretty smooth finish the painted finish looked good, I am a fussy git and this part of the jon took me ages as I rushed things and it went a bit pear shaped and some parts had to be redone, which was very frustrating - time and patience is the key here.
7. With the paint dry and surface smooth, I used a tiny little bit of Metallic T-Cut just to remove any last paint/blemishes that may have been raised or where dust had settled on it whilst drying - it was left on until dry and then rubbed off and using a microfibre cloth to buff gently up to a clean and shiny finish. The paint would have been dry by then so the T-Cut wouldnt have eaten into the paint that much.
8. The lacquer was then put on the same way as the primer and paint, but this is the hardest part for me to get totally right. If the lacquer is too far away when spraying then in the heat it dries up and when it makes contact with the painted surface leaves it looking like a moon surface, not good. I found that having the can 4 to 6 inches away, whilst using short bursts of sweeping movements, it would take to the paint. When spraying I looking at the painted surface and had to ensure that I could see reflected light/sunlight on the sprayed surface to be able to gauge how the lacquer was taking. As the lacquer sits on the painted (horizontal) surface I would see it start to form something like a watery layer, which has the lacquer forming a protective shell over the paint. At this point I stopped spraying, as I found sometimes to my utter disgust that the weight of extra lacquer would form runs/rivers/lava flows on the painted surface - If this happens its out with the 800/1200 wet paper to rub it down gently, when the lacquer dried obviously. Reapply the lacquer more carefully and let to dry which was very quick, around 10 minutes or so.
9. Now that the lacquer was dry I set about it very gently with 1500 wet paper to remove any imperfections and rubbed it dry, I then found that using the same Metallic T-Cut (i have metallic blue) used sparingly over the section brought about a very smooth finish. I then used some wax to provide a final protective layer, this took 3 layers of wax, just because i was a fussy bugger.
These methods above worked for me, I am in no way a professional and won't pretend to be one, my day job has me buggering about designing and building networks so the two jobs are far far removed from each other. If I had to do more, which I probably will attempt in the future, I would invest in some form of wind/sun/insect protection as I have no garage type protection to use and would use a gun and compressor to get more control over the paint and lacquering. I had lots of trials and errors and the outcome probably taken far longer than a body shop could do, but I aint a pro
If anyone can point Dave in other directions if they have better advice then mine please feel free
I hope this is of some use Dave,
Cheers,
Col