# DA machine polishing uneven panels



## TwoTwo (Feb 10, 2020)

Hi all,

I'm about to machine polish for the first time with a DA polisher and as you would expect i've been looking at various videos/product demos.

One thing that really bugs me with all the tutorials I've watched is that they demonstrate the technique on a bonnet that is perfectly smooth, and obviously make it look easy. But what about the uneven panels? Such as doors, boots, bumpers, bonnets with ridges and creases etc?

Does anyone know a good video demo of DA polishing a whole car including all awkward sections?

Thanks for the help

Ben


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## Lexus-is250 (Feb 4, 2017)

TwoTwo said:


> Hi all,
> 
> I'm about to machine polish for the first time with a DA polisher and as you would expect i've been looking at various videos/product demos.
> 
> ...


I've only used a da a few times but much more over the last month or so. What I've found is the need for smaller and larger pads and backing plates is essential. I ended up working with a 3 inch pad far more than the 5 and even that wont get into all the small places. You want it perfect but unfortunately it wont be just do what you can.

What products are you using?

I like watching white details as although the extreme end of perfect he has so many pads and machines that help him. We just dont have that. Just practice.

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## TwoTwo (Feb 10, 2020)

Lexus-is250 said:


> I've only used a da a few times but much more over the last month or so. What I've found is the need for smaller and larger pads and backing plates is essential. I ended up working with a 3 inch pad far more than the 5 and even that wont get into all the small places. You want it perfect but unfortunately it wont be just do what you can.
> 
> What products are you using?
> 
> ...


I actually haven't got a machine yet, but looking at a DAS-6 V2 once they are back in stock, as I know you can use smaller backing plates with it. I only have light swirls so I don't need anything too aggressive. Do you think that's a good option? Cheers!


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## Lexus-is250 (Feb 4, 2017)

TwoTwo said:


> I actually haven't got a machine yet, but looking at a DAS-6 V2 once they are back in stock, as I know you can use smaller backing plates with it. I only have light swirls so I don't need anything too aggressive. Do you think that's a good option? Cheers!


I have one of the argos da's that cost me £35 and has done well for what I've used it for. Many of the cars in the family are Japanese so can be corrected with a light polish. I've been using car chem finishing polish on most of these and tac systems one essential on mine with tac systems pads.

A simple polish will help you get the feel of things. As an example I did one of the son in laws civic last week and the polishing took about 5 hours. And that was rushing. It's better but not right by a million miles. It takes quite a bit of time depending on the car. You could start with something like bilt hamber cleanser polish or autoglym super resin which wont cut much but will make things look so much better, will also give you practice. If it wasn't for lockdown I wouldn't have done as much as I did.

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## TwoTwo (Feb 10, 2020)

Lexus-is250 said:


> I have one of the argos da's that cost me £35 and has done well for what I've used it for. Many of the cars in the family are Japanese so can be corrected with a light polish. I've been using car chem finishing polish on most of these and tac systems one essential on mine with tac systems pads.
> 
> A simple polish will help you get the feel of things. As an example I did one of the son in laws civic last week and the polishing took about 5 hours. And that was rushing. It's better but not right by a million miles. It takes quite a bit of time depending on the car. You could start with something like bilt hamber cleanser polish or autoglym super resin which wont cut much but will make things look so much better, will also give you practice. If it wasn't for lockdown I wouldn't have done as much as I did.
> 
> Sent from my SM-A505FN using Tapatalk


It does seem as though everyone has turned to car detailing in their boredom! I did the front quarter panel on my Mustang by hand with Meguiars Ultimate polish and I managed to remove all the swirls but it took forever and I don't think I even had enough energy left to move onto another panel, which is why I'm turning to a machine!

Thanks for the tips, will have a look at all those you suggested


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## Lexus-is250 (Feb 4, 2017)

TwoTwo said:


> It does seem as though everyone has turned to car detailing in their boredom! I did the front quarter panel on my Mustang by hand with Meguiars Ultimate polish and I managed to remove all the swirls but it took forever and I don't think I even had enough energy left to move onto another panel, which is why I'm turning to a machine!
> 
> Thanks for the tips, will have a look at all those you suggested


To be honest I was redundant this time last year and did a load of work on the house. This year I've done bits on the house but really wanted to do the cars so I did. I'd personally go with something like carpro essence as it covers all bases and doesn't need wiping down. You can then just add your protection of choice. A small bottle will last you ages and will be worth the investment.

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## Steampunk (Aug 11, 2011)

As you surmise, DA polishing in concaves and convex panel sections is where the skill is... It's important to find your balance on the flat sections, but you learn a new set of skills on the curvier stuff.

I can't say there's a YouTube vid I've found that really shows how it works, but I'll try to explain.

8mm free-throw DA's are great to learn this on. Contours are harder with long-throw, and kind of cheating with forced rotation, but you really learn your chops on the bog-standard, newbie-spec DAS-6 type machines.

Free-rotation DA's are like Autogyros/Gyrocopters. The pad doesn't spin because it's driven; it spins due to internal bearing, and external surface friction. It only _orbits_ under power. You need to keep it spinning as well as orbiting, and not let the rotation bog to zero RPM, or you lose both correction and finishing ability.

This will make the most sense once you own your machine, but let's go through a couple of DA drills to get you familiarized with the handling of your tool.

Unless you get a scrap panel, you need some Dodo-Juice Lime Prime Lite (The only truly non-abrasive product I've found with a decent working time.), and a finishing or polishing pad... Pad-wise, on an 8mm free-rotation DA, I'd suggest CG's Hex Blue or White for this practice. Make a mark on your backing plate with a marker, so you can observe the RPM's.

Start on a flat section. Put a couple dots on the pad, spread over an 18X18 inch area on speed 1, then up to speed 3-3.5. Let your hands relax, and adjust your grip until the machine find its equilibrium, where it feels 'balanced', and the pad rotates quickly without resistance. This is the center, or 'eye' of the storm. Put more pressure straight down, and watch the RPM's slow by observing the mark on the backing plate.

Lift up again, and find that free-running equilibrium. Now, shift your balance to point to each point of the compass, and watch the pad slow. Shifting the balance shifts the pressure to a different point of the pad, and increases PSI in that section, at the expense of RPM.

When you're on a flat, the equilibrium point of the pad that allows max rotation, is centered on the pad. When you're on a convex surface, the equilibrium point moves outwards. You're balancing the pad and inch or two outside the center. As you get closer to an edge, you balance the pad closer to the edge of the pad surface, while still keeping it rotating. The further from the center you are balanced, the less pressure you apply to the machine. Practice, and feel/watch it.

On concave panels, you're polishing more with the edge of the pad, into the radius of the curve. This can actually be practice on a flat panel, by tilting the machine at as high of an angle as you can, and still maintaining rotation through careful pressure control. You're just shrinking your contact patch of the pad, from a large circle, into a small oval. You should be able to polish a roughly 1" wide line, with a 5.5" wide pad, on an 8mm free-throw DA. It just takes practice.

With DA's, you have a zone of the pad most don't factor, called the Partial Contact Zone (PCZ). When you watch a DA spin, there's this ghostly area of the pad around its periphery that's semi-transparent, that reflects the orbital length of the machine. This is the most important zone of a DA, because it's the least efficient. It's a semi-dead-zone. Your correction here is maybe at most 40% effective, versus the rest of the pad. When you're getting close to obstacles or edges, realize that this semi-transparent pad area, isn't working as hard as the rest, and the rest is working harder. It's a soft-edge. Like shaving with a Double-Edge versus a Straight. The DE won't get as precise an edge on a beard as a straight, because you lack edge definition.

With an 8mm free-throw DA, don't go too much below one RPM per second under full (Count to one-one-thousand until you see the BP mark return to the same point.), or off-axis pressure.

You can get an 8mm or less DA into contours... It just takes practice.










This was obtained with a Meg's G110 V2, 8mm free-throw DA, after wetsanding. You can do it too, on almost any contour with this sort of machine.










The MGB front fender transitions from a almost 90-degree angle, to a shallow concave, with a convex outer. You can polish all of this with a basic 8mm free-throw machine, with the right technique. It just requires sensitivity, to feel the frictional balance, as the contact patch moves from the center of the pad to the edge, depending on what area you're polishing. You also have to keep in mind, the effectiveness of the PCZ.

Hopefully, this helps...

- Steampunk


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