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polishing thread?

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Sesman:
Ta.

Laverdaroo:
I know the black/dark grey ones are the most abrasive but not sure on the scale of abrasivness of the other colours.
I think its that they get less abrasive the lighter the colour but if you ask Ken he will know

Oddjob:
So many questions to answer.

Discs, get them from the Amazon link Roo put up, ccurrently not available I see but wait until they are, there are others the same for sale on Amazon but not as cheap, however if you're desperate a quick search for abrasive brushes will show them. If you look my review of them is at the bottom of the page.

They come in different colours, the Dark Green is most abrasive at roughly the same as 80 grade wet/dry. Then Dark Blue 120, Red 220, Light Blue 400, Purple 600, Light Green 1000 and finally White 2000. White is like a pumice stone, you can't really use it on alloy but on brass or a soft metal they'll give a nice finish. I tend to start with either Dark Green or Dark Blue, 2 on a mandrel, you can use 1 if you need to bend it into a corner or a curved surface, use at 90 degrees but keep altering the angle of attack so to speak or you'll dig a trench in the alloy. Occasionally lay one on it's side, virtually flat to the surface for reaching into places. So look at the piece you're doing, is it in bad condition? can you see dents, gouges or deep scratches, if so Dark Green is your friend. Just don't press hard, I cannot emphasise this enough, you press hard and 3 things will happen, firstly you'll dish the metal or dig a trench as I like to call it, secondly, the fronds will start to detach and they will hit you in the face and lastly and most importantly, you'll burn out the Dremel, been there, done that, 3 times already, luckily 2 were replaced under warranty. I have 4 Dremels and use 2 of them at a time, keep feeling the Dremel body, when it gets hot change to the other to allow it to cool down. If you haven't got a flexible extension for your Dremel get one, you'll never go back to using a normal Dremel again. If your buying a new Dremel buy the 4300, it's FAR better than the 4000, I've burnt 3 4000s as I said.

So, look at the piece, if not too damaged and lacquer all discoloured and dirty isn't damage, then start with Dark Blue or even Red. You'll grow used to how to get the best out of the discs, I can't explain it but you'll soon find what works best for you. I still experiment even now to see if I can find a better way, do the whole surface first, don't stop when you spot something, you can spend ages working on a small area and then find a huge crack hiding under the lacquer which means the piece is junk. So after doing the entire surface go back to the problem areas, now here's where it gets a little contentious, I maintain the cases etc are painted and you'll soon see why I say that, as you sand you'll first start to see the lacquer just melting away under the brush, then you'll see the paint layer come off, then you'll hit alloy. You'll tell each one by the colour, keep turning the piece to catch the light as you need to see shadows etc, they show where damage is better than the naked eye. When you see the entire piece naked of lacquer/paint then you'll see what I've always said, jesus these things are not cast very well, there are flashings on the edges not been removed, injectors marks in the surface, ripples in the surface, swirls and small pits that the paint etc was covering up. What looked like a decent piece before suddenly looks awful, sometimes better but mostly awful and here's where doubt steps in. You really wish you hadn't started this and you'll get that feeling again and again, keep going, it gets better. Use the brushes creatively, I call it sculpting the metal and after a while you'll find you can actually shape it before you're eyes.

Each bit of damage needs it own solution, pits, just keep going over them and removing microns of metal at a time, first have a visual check, is there enough metal there to be able to remove some safely, depends on the piece TBH, if it's a safety piecce, like the brake caliper arm then don't go mad, if it's just a cover and it doesn't really need that much strength then you can go a little harder. Don't be afraid to remove the surface, I've only gone through one casing ever and the damage was so bad beforehand I only did it to see if it was possible to repair it, it wasn't so it went in the junk pile. Things like brake plates are VERY thick, they can withstand quite a bit, camshaft end caps are essentially decorative, they seal oil yes but the alloy is just a way of supporting the O-Rings, you can remove quite a bit if needed. Assess first and if the damage doesn't appear to be going away after a few minutes then leave it. Really deep gouges, like road rash from sliding down the road, use a file first, get brutal, the marks will go away with the Dark Green brush.

Sorry this is so long winded, so you've done the surface, all the marks have now gone or you've accepted you can live with them. The surface however is rough, you can see marks left by the fronds etc. Go up a grade of brush, go to Dark Blue if you used Dark Green etc, lightly just run it over the surface, leave it to linger a little in bad areas and you'll see the surface getting smoother and smoother, you'll also see odd stuff in the surface, like swirls in the alloy. don't ignore them but don't worry we'll deal with them later. After doing it with the next grade go up again, now the marks the last grade left will be removed etc. Keep going until you're happy, I usually stop at Light Blue as by this time it's time for the polishing mop to take over.

I'll stop here in case it's boring, I know it's boring just writing this down, god knows what it's like reading it.

Let me know if you want me to continue onto the polishing process but in answer to Roos question, buffing compound or soap grades, Dark Grey is REALLY abrasive, then Grey, then on alloy use Brown, then White. I finish off with pink these days for a deep lustre.


Oh and before I forget, I don't normally use any hand sanding at all these days unless the surface is tubular, like a fork slider. Forget hand sanding, it's ineffective, time consuming and hard work, let the Dremel take the strain.

Sesman:
That’s good info Ken…..keep it coming.

Laverdaroo:
BAZINGA!!
Top write up Ken ;)

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