Specific Questions about polishing

Discuss anything after that final masking comes off.



Settled In
Posts: 56
Joined: Tue Dec 03, 2013 10:53 pm

Country:
Australia
PostPosted: Mon Mar 23, 2015 1:25 am
After a new paint & sand out all imperfections with 2000-2500grit. the colour is dark metallic blue

There is a 3 step approach.

1-orbital polisher with rough compound using 3M white pad.
2-orbital polisher 3M swirl remover with black pad.
3 using the vibration type polisher with ultrafina & 3M blue pad


Any suggestions or corrections? Thanks

User avatar

Top Contributor
Posts: 2762
Joined: Sun Dec 16, 2012 4:46 am
Location: Canberra
Country:
Australia
PostPosted: Mon Mar 23, 2015 3:43 am
Ok, so let's get some terminology straight.

Rotary: Looks like a big angle grinder and the pad rotates about a central axis.
Random Orbital: Varying styles but looks more like a sander. Pad moves about a small axis, anything from 2-10mm. The pad does not rotate. Usually used as a sander, 1/2 sheet, 1/3 sheet or the detail style. Not usually used for polishing
Dual action: The pad moves in a random orbital motion but can also rotate, although rotation is not driven. Air or electric.
Forced rotation: A combination of rotary and dual action movements. The rotation is driven, as is the random orbital motion. Top end, expensive machines.

Here's a picture of the movements (thanks to Meguiars)
Image


Most painters start the wet sanding process with a bit coarser than P2000. I like to use P1500 on an air DA. Then go to P2000 and finally P3000 (using 3M Trizact).

I then buff with a rotary machine using a medium pad and a compound that breaks down (becomes finer) as it's used. I use AutoSmart Sophisticut, but there are lots of others). At this point I have a good to quite good shine, perhaps with a little swirl.

I then use a dual action machine (Cyclo) with medium pads and a swirl remover/polish. Again, in my case, Gelson T57 for dark cars, T47 for light colours but again lots of others.

That's it. Mirror shine, zero swirl.

There are lots of variations. Some buff straight from P1500 wet. With a nice soft clear that's fairly fresh, this can work, too, but needs a bit more work on the buff. Others may add a glaze at the end - I don't need to, it's in the product I use.

The colour of the pads varies from manufacturer to manufacturer and what is available in the US may not be available (or affordable) here. I use Contour pads, locally made and the white pad is medium cut, orange heavy cut and black is very soft, for final finishing.
Chris



Settled In
Posts: 56
Joined: Tue Dec 03, 2013 10:53 pm

Country:
Australia
PostPosted: Tue Mar 24, 2015 1:10 am
thanks,


Is the vibration type polisher needed at all? Maybe only on dark colours if so?

who uses this type?

EDIT: when finished with the pads, do you clean most loose compound off & just leave them? Wouldn't it dry out on the pad & scratch the next job?



Fully Engaged
Posts: 216
Joined: Mon Mar 11, 2013 1:50 am

Country:
Australia
PostPosted: Tue Mar 24, 2015 11:34 pm
I just run a plastic filler blade across the foam pad with it running gently to clean off excess dried stuff before next job but i'm a rookie lol



Settled In
Posts: 56
Joined: Tue Dec 03, 2013 10:53 pm

Country:
Australia
PostPosted: Wed Mar 25, 2015 1:52 am
So as I understand, even on a small backyard job you want perfect, I would need a rotary buffer to deal with the 1500-2000grit hand sanding marks? ( I sand dust & runs out by hand). And that a orbital or d/a would not get those sand marks out or take way too long? The d/a is the next finer step only. I have seen a rotary in action, the user just keeps given pulses of power rather full ON. & it got those sand marks out.


When I spoke of vibration, I actually thought there was a pure vibration type of polisher, different to a d/a

If someone could please correct me.



Fully Engaged
Posts: 216
Joined: Mon Mar 11, 2013 1:50 am

Country:
Australia
PostPosted: Wed Mar 25, 2015 2:03 am
get onto youtube and watch customspraymods he shows you how to get great results with cheap products.

http://www.autobody101.com/forums/viewt ... ha#p177307

this is $10 supercheap auto acrylic laquer color + clear + wet sand 1500 + cut/buff with meguiars 105 wool pad an 205 foam pad off cordless drill... the only quality product was the meguiars everything else was cheap cheap cheap...
you dont change polisher - just the pad and the polish/compound

what have you painted? a car metallic blue with clear coat?

wet sand with 1500 then buff out with wool and cutting compound to remove sanding scratches and then foam finishing pad to remove fine scratches/swirls

using an orbital polisher wil increase speed of cut with increased risk of burn through and other polishing induced errors/defects I have not ever burnt through paint even when being pretty aggressive...

if its a cheap cheap cut and buff just by septone mrbuff from supercheap it progressively breaks down under an orbital polisher with foam pad into a finer grit, you get it pretty reasonable without need for a second stage, just a quick wipe down with polish at the end can be enough..

I use meguiars because it protects the paint, is silicone free, low VOC etc

Return to Cut, Buff, Polish & Detail

Who is online

Users browsing this forum: No registered users and 21 guests