I need some guidelines for machine polishing

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kajaalyo

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Hello,
I had just finished with first time machine polishing my black car and I have some questions about it.
It camed out nice, no holograms, swirl marks or other added defects thankfully, but I know that I could remove more scratches that I did based on the before after pictures I have seen.
First about my setup that I had bought:
Bosch GPO 14 ce polisher (yes I know it`s not a DA and it`s kinda big, but I got really good price on it)
135mm disc with soft (rubber) edge
3M Fast cut plus, Extra fine and Ultra fine (anti hologram) polishes with matching green, yellow and blue 150mm pads
Bilt Hamber Auto Clay soft
Gold class carnauba plus paste wax


Car was washed and clayed, now to the problems.


As I started the polishing I discovered what people in tutorials mean by "you must get the filling when using machine polisher, polisher must move by itself", polisher was dragging, jumping... but I managed to get that filling fast.
I polished the hood, the roof with Fast cut plus and green pad, but problem started when I started with the doors.
Thepad was dragging like crazy, like I would want to cut something with angle grinder with too much pressure...
I washed the pad, thinking I have too much of polish in it. It was much better after that, but still there was alot of drag.
I think that this has to do with panel being curved horizontaly and verticaly at the same spot...
I couldn`t polish some really curved places at all, I ended doing them by hand.
Next step was polishing with yellow pad and extra fine polish... that went well.
Finaly I polished everything with blue pad and ultra fine polish, again there was alot of drag, but I managed to polish 90% of car by machine and finish some really curved parts by hand.
I washed the car really good and waxed it... That also went well.
I ended with mirror like finish, swirl marks completly removed, alot of scratches removed, but alot of them (not deep) remaining.


Now I have some questions:

Why do I get so much drag with fast cut plus and green pad on curved areas?

How big of an area should I polish at once? I did half of hood at once (It felt that it was a bit too much), half a door at once, 1/4 of the roof at once, ... the car was Opel Asta H GTC.

How long should I work with the same polish? I did about three passes, if I did more polish was hard too remove, like it was starting too dry.

Why do I sometimes get hard spot of polish right after I apply? Maybee a bit of water from under the trim can cause this?

Why do I sometimes get dust flying around right after I apply the polish? Can I continue to polish with the dust or do I need to clean and reaplly the polish?

What should my speed setting be? I polished with setting 3 (1500rpm) but the paint didn`t get much warm. I was told not to use higher speed setting to avoid burning the paint.

Why I couldn`t remove some scrathes that I specially focused on and weren`t deep? Too low speed setting?

If I choose to sand some scratches can I sand just the scratch and fade around it or do I need to sand the whole panel?

It would be really handy if I had smaller polisher with smaller pads for some hard to reach areas, but I`m not planning to buy it, however I have small disc for drilling machine. Can I use that or will there be a visible change in the finish?


Thank you for your help, I know that you can`t tell everything for sure because you weren`t there to see what I was doing, but some guidelines what I could try would be helpfull.
 
Welcome to AutogeekOnline! :welcome:

I started typing out answers this morning at 9:00am and then moved onto writing new product reviews.

Need Some Help with the Waxing Process



Actually started here, I think you were one of the people I approved?

https://www.autogeekonline.net/foru...approved-spammers-removed-15.html#post1674439




Being that it's almost 6:00pm, I'm logging off for the day. I hope others will chime in with their help. One thing I would HIGHLY recommend on this forum or ANY social media platform and that is when asking questions - start with just a FEW. Like 2-3 questions.

This makes it easy for someone else to type out answers. When you ask a LOT of questions - because it means a lot of typing, really good natured people will simply >click< away.

In fact, I have an article o this,

A tip to help yourself get great answers when you start a thread


I'll be back in the morning and check on this thread first thing. It's my nature to work long hard days but I don't want to get divorced.



:)
 
I'll do my best to answer your questoins....



kajaalyo said:
Now I have some questions:

Why do I get so much drag with fast cut plus and green pad on curved areas?
Click to expand...

That's the nature of the beast for "some" product and pad combos plus anytime you're using a rotary buffer. Try smaller pads and this will help or try different products. Instead of holding the pad flat to the surface you can instead,

Go up on edge

This will make buffing with a rotary buffer a lot easier but will be a LOT more prone to inducing holograms.


kajaalyo said:
How big of an area should I polish at once? I did half of hood at once (It felt that it was a bit too much), half a door at once, 1/4 of the roof at once, ... the car was Opel Asta H GTC.
Click to expand...

Half a good is a tick large for any paint correction or compounding work. If a person is highly skilled then polishing, (not compounding), can be okay for half a hood. The rotary buffer has a lot of power - it's just how much power do you have? There are techniques for using a rotary like keep your feet shoulder-width apart with one foot a little in front of or behind the other foot so you have a solid stance for your upper body to then control the polisher.


kajaalyo said:
How long should I work with the same polish? I did about three passes, if I did more polish was hard too remove, like it was starting too dry.
Click to expand...

Maybe try using more product and clean your pads often? I haven't used 3M products for a long time but it's a fact they make great products.

What's the temperature, humidity and wind like where you buff?


kajaalyo said:
Why do I sometimes get hard spot of polish right after I apply? Maybe a bit of water from under the trim can cause this?
Click to expand...

Glass Cleaner. Most glass cleaners contain about 10% Isopropyl Alcohol and this and the water will break-up the oily film of compound or polish.



kajaalyo said:
Why do I sometimes get dust flying around right after I apply the polish? Can I continue to polish with the dust or do I need to clean and reaplly the polish?
Click to expand...

The dust is dried product coming off your buffing pad. I'm assuming at this point you're using a foam pad? If so, clean the face of your pad with a nylon brush - you can use a toothbrush.



kajaalyo said:
What should my speed setting be? I polished with setting 3 (1500rpm) but the paint didn`t get much warm. I was told not to use higher speed setting to avoid burning the paint.
Click to expand...

Try buffing around 1000 and see if that works for you. Generally speaking, a little speed can actually make it easier to control the rotary buffer but it all depends on the pad and product.



kajaalyo said:
Why I couldn`t remove some scrathes that I specially focused on and weren`t deep? Too low speed setting?
Click to expand...

Removing a scratch means removing paint. Removing deeper scratches means removing more and more paint. Be careful, the factory clearcoat on modern cars is thinner than a Post-it Note.




kajaalyo said:
If I choose to sand some scratches can I sand just the scratch and fade around it or do I need to sand the whole panel?
Click to expand...

You can sand just the scratch but I would "feather-out" around it. The issue or "problem" is that when you sand factory paint you remove the orange peel in that area. It's possible to look at the panel and see the spots that now have no orange peel as they will contrast against the areas with the factory orange peel.


kajaalyo said:
It would be really handy if I had smaller polisher with smaller pads for some hard to reach areas, but I`m not planning to buy it, however I have small disc for drilling machine. Can I use that or will there be a visible change in the finish?


Thank you for your help, I know that you can`t tell everything for sure because you weren`t there to see what I was doing, but some guidelines what I could try would be helpfull.
Click to expand...


When you sand with a drill or a rotary buffer it's no longer called SANDING - it's called GRINDING - DON'T DO IT.



I actually answered some of your same questions already this morning in another thread. My answers in that thread apply to your thread. In the next post I'll share the thread and then just copy and paste what I have already typed-out today.


Good questions - you would be a lot better off with an orbital polisher.



:)
 
Here's the other thread,


3M Foam Pads with DA Polisher (Compatible?) + Your detailing guide


Here's the portions that apply to you....


kajaalyo said:
If I choose to sand some scratches can I sand just the scratch and fade around it or do I need to sand the whole panel?
Click to expand...




Clearcoats are thin by Mike Phillips


Just how thin is the clear layer of paint on a factory paint job?

The factory clearcoat on a new or modern car measures approximately 2 mils thin.

The average post-it not is around 3 mils thin.

watermark.php





So tread carefully when sanding factory thin paint - especially horizontal surfaces as these get tortured by the SUN and this is were clearcoat failure happens first.


Click and read my article here,


Wetsanding removes paint - Compounding removes paint - Polishing removes a little paint



:)
 
Thank you very much. You got me all covered. Yes, we were texting on email for approval.
Yes, I asked alot and thank you for anwsering everything for me.
Next time I will do smaller areas at once, i have the power, but it`s hard for me to hold the polisher under the correct perfect angle with my hands stretched out.
Temperature of my garage is around 20celsius in that time of the year, no wind, but humidity is high because the garage is right next to the woods. I will clean my pads more often, I apply 5 about 0,7cm big drops on my pad and rub them onto the car and start at lowest speed to spread the polish, I tryed to use more, but polish was flying around.
Yes when i get the dust I`m using the fome pad, I will clean it with the brush next time.
I will try 1000rpm speed especially with green pad and extra cut to minimize the grab.
I totaly forgot about the orange peel, it`s better to sand the whole car then.
It`s a daily driver, I know I overcomplicate things all the time, that is just the way I am.
I will also check the wetsanding and when to stop buffing topics.
Next car I will do is Astra H vagon, same black colour, I will also try to get black bonnet from the junkyard so I can practice on it and to get a filling of how much I can polish before I burn the clearcoat.
I hope I master this soon, but it`s hard for me because I always have more things to work on currently a full restoration of third gen camaro, DIY android headunit for it, now the new hobby the polishing together with auto electrician job working overtime most of the week.

Thank you again for anwsering all the questions for me, you helped me alot
 
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