Stutopia Posted September 28, 2017 Author Share Posted September 28, 2017 6 hours ago, Paul K said: Great thread Stu.....Have you invested in a smaller backing plate yet? i got a 75mm one and some smaller MF pads for my polisher, really helps on tight areas I've got a 75mm as well as the 125mm, I must admit I find the 3" pads to be much more friendly and they seem to suit the DA and it's lack of grunt a bit better too. Quote Link to comment Share on other sites More sharing options...
Stutopia Posted September 28, 2017 Author Share Posted September 28, 2017 The 3000 grit 3M pads arrived and look like this and felt like a sort of nice leather. After giving the bonnet a going over with it, I found I had a slightly less dull finish and much more even sanding pattern. There's not much in the way of instruction on the packet, so I tried number 6 and a lot of pressure (see below damage) and then number 3 and next to no pressure, nothing really felt perfect - as you can see from the image below. Nice uniform dullness. I started to think that hand sanding the 1200 grit wasn't such a swell idea, the machine does a much better job. Well except where I crank it up to 6 and lean on it. Whoops. After wiping the clear coat/water slurry spray off my hoodie, I eased down and gave the MF cutting pad another spin with 105. Yeah, I still don't like the 5" MF pads, so I switched to the god old 3" foam pad. Which left me with this. Plus a number of deeper scratches that I thought had been sanded away, but it turns out, hadn't, or, perhaps may have even been introduced by me and the shambolic hand sanding phase. Tomorrow should bring more 105 and polishing pad fun. Quote Link to comment Share on other sites More sharing options...
Stutopia Posted September 29, 2017 Author Share Posted September 29, 2017 After giving the bonnet a full third stage (105 on a polishing pad) of a projected 4 stages, I was hoping the dull 3000 grit sanding marks would transform into a gloss surface, ready for a final 4th stage of Menz SF on a finessing pad to make a mirror surface. Well, you know what they say about best laid plans... Stage 3 left me with some nice gloss (as hoped for) and some rather unsavoury deep scratches (not hoped for). Many of these deep scratches I know weren't there before I started, they came during the 1200 grit hand sanding stage. Somewhat disappointed, but not disheartened (who gets it right first time?) I decided to isolate these and have another go at them. So I taped up and went in again with the 1200 grit by hand, leaving me a nice dull square. I'd chucked out the first 3000 grit sanding pad, having ripped it on a edge, so I had to do some surgery on my remaining one. Making it more or less fit the interface pad. Before (1200) on the left and after (3000) on the right. Since playing with the 3000 grit pads last time I'd read that when using them on a sander a typical speed might be 1200rpm, which I'e been way over, so this time I slowed it down and reduced the pressure. This worked better. It goes without saying that it's night and day between the two, the strip light can be clearly seen on the right but is lost on the left. It's amazing how the paint can be brought back from this kind of damage, not once, but twice. I'd love to have had a Paint Depth Gauge to know how much was coming off at each stage. Sadly, after moving on to one pass at stage 3, the deep scratches will still present. You can clearly see below the well defined corner where the masking was for the hand sanding. I could have gone back to the 3000 grit for more goes, but I wanted to see what the 105 could do if pushed. After another few passes with 105 Here you can see what happens if you get a bit impatient and lean on the DA with everything you've got, a truckload of dusting Another round, getting better. Now we're getting somewhere, Round 4 - at this rate I'l be looking for a decision on points, not the knockout I'd hoped for. The MF towel shows where the edge of the masked area was before, it's no longer visible to the camera. Initially I'd planned to do a full 4th stage on the whole bonnet with Mens SF and a finessing pad, but looking at the chunks of missing paint and dents and deep scratches, there seemed little point (I now wish I'd got a bonnet in better shape). Instead I tried to find a small section which was all paint and no chips, to see what could be done with a focused effort. I ended up with this tiny section. I could have taken this approach right from the start, working a small section to death, but I wanted to try many products side my side for comparison and I wanted the most amount of time with the DA to get used to it's weight, movement and handling over ridges and panel curves. This meant that by the end of my experimenting, (15 hours or so in total) I was concentrating on the paint and not so much on the DA itself. After stage 4, I finally got to what I was hoping for, that nice mirror finish that black paint has lurking under the surface. This represents the last of the work I can (be bothered) to do to this panel, there's no point taking it any further, it's a waste of product and time. My next go will be on a relative/friends shed, or another scrap panel, but I'll be careful to get one with fully intact paint - not blemish free, but not with gouges either. This bonnet cost me a cool tenner, which is less than the bottle of 105 What have I learnt? If you want to learn, when someone experienced tells you to get a scrap panel to play with - this is excellent advice, do it. When you get told that only a total banana can do damage with a DA, it's true, but it's also nice to know first hand just how over the top aggressive you can be, see above. Hand sanding didn't really work for me, it's impossible for me to be consistent with it - I'd want 1500 grit discs and a dedicated sander to do it again. Megs 105 is very impressive, it can really shift defects. Dust means too fast or too much pressure. Hand speed is apparently more important than the amount of downward force I can apply. Slow passes can really mow down peaks. So far, I like oily polishes (Menz), they can be worked forever. Less product is more product (excluding pad priming). Buy more microfibre towels. Anyone who can get black paint close to 100% defect free deserves respect! 2 Quote Link to comment Share on other sites More sharing options...
Ricey Posted November 1, 2017 Share Posted November 1, 2017 Stu it would appear you are fully immersed in the dark side. Looks like you've been learning some good stuff. I could waffle on all day but let me give you 2 key pieces of advice. Wet sanding is insanely difficult. So many polishes will tell you they remove 1500 grit or 1200 grit......bollocks. You'll really struggle to remove the etching that they will impart on the bodywork as you've got to level out the trough the grit makes in the paint. You may get a much flatter glossier finish but sanding tracers can be a major issue. 2. Perfection is a myth. Always be prepared to know enough is enough. If what appears to be a shallow scratch is 1/10th of a mm thick bear in mind that paint is IRO the thickness of a £5 note and you are working on around 50%of that thickness......i.e not a lot. 1 Quote Link to comment Share on other sites More sharing options...
Paul K Posted November 3, 2017 Share Posted November 3, 2017 After i got my DA, the very next thing i invested in was a PDG....a reasonably decent one can be had for £90ish CEM-156 is what i have...it was recommended on DW website Quote Link to comment Share on other sites More sharing options...
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