3rd June began working on the flashlines. after a few hours of this I realise you have to be pretty meticulous with the sandpaper steps – I thought I was being very careful as I went through the grades but each time I finished the fine machine polish/cutting stage I could see micro scratches left by my less than perfect sanding operation.
- Step 1 Mask up and scrape off as much excess as possible without adding further scratches. I used a thick blue masking tape to mask and a variety of scrapers.
- Step 2 Sanding, I started with 800 then 1000 then 1500 grit, I was generally wet sanding with lots of water and I eventually realised its very important to thoroughly dry off between sanding layers and check for micro scratches, by the time you get to 15oo I needed to aim at having a smooth matt finish with no sign of micro scratches caused by the heavier grades used in the earlier steps. only then move on to the machine polishing. I’m half way down one side of the car by the time I’ve figured this out… maybe I’ll know what I’m doing by the time I finish.
- Step 3 Machine cut/polish, I’m using two steps here firstly 3m green top fast cut(50417), followed by 3m blue top ultrafina (50383). After my first attempt I achieved an excellent shine but could see lots of micro scratches (they become more visible at this stage) .Obviously I hadn’t carried out step 2 correctly. I went back at it with 1500 grit and ensured I got rid of the scratches, once you know what you are looking for with these very fine scratches and are able to get rid of them with the 1500 grade, it all becomes much easier to achieve (it still aint easy though!).
For the machine polishing I’m using a small 3″ detail air polisher but I’m sure any polisher would work, I think its mostly important that you use the correct mop/sponge head for each grade and also don’t go too slow or too fast I guess I’m working somewhere in the 1200 to 1500 rpm area. only use as little compound as necessary, once polishing the compound should gradually disappear, if it doesn’t then I’m probably applying too much. I also found it best to concentrate on a small area at a time maybe no more than two sq feet or even less. I plan to do final polishing/wax with a larger mop head over the complete car once I get everything to this stage.
Prepare to get wet and messy… I found this little scraper from one of those vibrating tool sets (Aldi) ideal for stage 1 it has a slightly curved scrape edge which means its difficult to scratch other parts when scraping off the excess flash lines, although I also used a variety of fine files. Mainly using the 3m green top and blue top for stage 3 and the little Kobe polisher from Cromwell tools, the green sponge mop is for the green cap “Fast Cut” and the black (very soft)sponge top left of picture is used for the “Ultrafina” blue top.
Marks Cobra Build 