Help me understand DA speed

[Riff]

Just got the Harbor Freight DA with Lake Country 5.5" pads. Used it for the first time yesterday on my pretty neglected but still not terrible 2003 Mazda MPV. Silver hides swirls good!

I used an orange pad with Meguiars Ultimate Compound, then white pad with Meguiars Ultimate Polish. I'm pretty happy with the results considering my first time and this is just practice for my other vehicles.

From reading up here, I used speed 5 for the compound and 4 for the polish but now that I'm thinking about it, wouldn't a high speed and very slow arm speed be better for a polish? It seems like a high speed, very light pressure and slow arm speed would give a better finish.

Can anybody explain why use a higher speed for compound and a slower speed for polish?

[rolop6]

Depending on the severity of the car, the pad and the compound/polish is the speed that needs to be used. If your correcting a severely neglected finish your need the speed to cut through the clear(5-6). If your polishing minor defects (4-6) might work. A wax (3-4), cleaner wax (4-6). You have to determine what speed you need based on the defects and the combo of pad and polish/compound. That's what the test spot if for, to help determin pad, product and speed necessary to get the results you want.

[Riff]

Thanks. So a higher speed might work for a polish. I'll try that out on my next test run.

[Kyle_Elantra]

You're right, less pressure can potentially lead to a better finish.
I suggest using your normal amount of pressure for your first couple of passes, then letting up on the pressure and letting the weight of the machine do the work on your last few passes.

You don't want to use no pressure at first - this will not allow the polish to do its work. I've always had success finishing the polishing step by letting up on the pressure.

As for the speed, you want to be more aggressive when compounding compared to polishing. When polishing you're really just refining the haze or tiny scratches remaining from compounding - you do not need high speed and aggressiveness to accomplish this.

Moderate machine speed, slow arm speed, and lessening pressure will help you refine your polishing.

Of course, as stated above, do a test spot and realize that every paint is different. Sometimes higher speed for polishing makes sense, but - for me and the paints I've worked on - it usually doesn't.

[Riff]

Thanks!

👍

[allenk4]

Depending on the severity of the car, the pad and the compound/polish is the speed that needs to be used.

If your correcting a severely neglected finish your need the speed to cut through the clear(5-6).

If your polishing minor defects (4-6) might work.

A wax (3-4),

cleaner wax (4-6).

You have to determine what speed you need based on the defects and the combo of pad and polish/compound.

That's what the test spot if for, to help determin pad, product and speed necessary to get the results you want.

There are simply too many variables to state this speed for compound...this speed for polish, etc.

-Compound aggressiveness

-SMAT or DAT

-Pad Aggressiveness

-Temperature

-Pressure

-Number of passes

-Hard clear-coat or soft

-Single stage paint


Mike Phillips has loads of information on the Forum on how to do a proper Test Spot.

This is IMO, the single most important thing to learn.

It will allow you to get the best possible end result, while saving time and clear-coat.

[Tato]

I'd like to add that pressure or no pressure may not be determined just by the task at hand, it's good to avoid making 'generalizations'... pressure is added to engage abrasives 'against' paint, and I use it even with finishing polishes and finishing pad.

Even if using a finishing polish like Menzerna SF4000, it has a cutting ability of 4/10 on Menzerna scale. That's almost half abrasiveness of a compound, so I see no reason to not engage the abrasives over paint with some added pressure.

As your polishing cycle goes (3-4 first passes) and you see (yes, SEE!) abrasives signal of properly broken down (product turning transparent), then you may reduce pressure to do the last 2 passes and finish in a glorious manner.

See, it's not 'crazy pressure' as a grinding process, but in order to work abrasives down you'll need to properly maintain your pad firm and flat on surface, and ease on pressure at end of cycle.

Some see heat as the main responsible for abrasives break down. I don't see this way, and avoid heat at any cost (although impossible, it's a collateral effect of polishing process). I see the friction as a more important aspect to properly work product down.

IMO, if you barely exert any pressure, odds are you'll not work product in a effective manner, and you'll have many cons on that, like not being effective enough on your approach, and not working abrasives properly may leave you with a difficult to remove residue. Also, your perfect finish may be sacrificed by this ineffective approach.

Again, this is not a generalization as well, but trying to understand how to work a product to polish and effectively remove small amounts of paint is the way to go.

This approach I've told above may be totally different if using Meguiar's SMAT products where abrasives have a defined size and won't break down to smaller size throughout polishing cycle.

The same goes for speed. I've saw a thread earlier that demonstrated how slow speed (but plenty) may promote (theoretically, at least) better finish.

I'll try to find it and place it here.

Hope that helps.

Kind Regards.

[Tato]

Here it is:

Post #10 of this thread.

***In advance, I don't know if Autopia thread can be shared here, if so, please, forgive my fault and cancel my post. Thank you in advance.

KBM- Pad Priming and Supplemental Wetting Agents - Guide to Detailing - Autopia (http://www.autopia.org/forum/topic/121000-kbm-pad-priming-and-supplemental-wetting-agents/?p=1309667)

Kind Regards.

[allenk4]

Here it is:

Post #10 of this thread.

***In advance, I don't know if Autopia thread can be shared here, if so, please, forgive my fault and cancel my post. Thank you in advance.

KBM- Pad Priming and Supplemental Wetting Agents - Guide to Detailing - Autopia (http://www.autopia.org/forum/topic/121000-kbm-pad-priming-and-supplemental-wetting-agents/?p=1309667)

Kind Regards.

Autopia and AutoGeek are both owned by Palm Beach Motoring Group

[Tato]

Thank you for info!!

[Angler]

Question for you, Rafael. You stated in your excellent post above, "As your polishing cycle goes (3-4 first passes) and you see (yes, SEE!) abrasives signal of properly broken down (product turning transparent), then you may reduce pressure to do the last 2 passes and finish in a glorious manner."

How do you "see " this on white paint? :confused: Please tell me your trick to seeing this happen as I can't see it. Thanks!

[FUNX650]

Autopia and AutoGeek are both owned by Palm Beach Motoring Group
You may just have the Autopia (that Tato posted)...
confused with the one owned by PBMG: Autopia-Car-Care.

Bob

[Tato]

Dear Angler, thanks for the above question!

How to answer, is for sure a challenge for me.

I've just delivered a white car yesterday (!) and I'm doing my best to remember how I did to see polish properly working on white... and I'm known for having good memory!

Sorry, I can't give a precise / definitive answer because I just can't recall exactly, I'm somewhat adapted to menzerna polishes that nowadays this comes 'automatic'...

Monday / Yesterday I've used SF4000 on white car and maybe for the polish itself being 'silver' in color, it helped seeing the change so this difficult was not faced, I believe that's why I can't recall this issue you're relating.

It's like the polish film is 'heavier' on the start (sure, plenty of product), and then it start turning transparent and all you see is the gloss behind a very thin film. 'Turning transparent' may not be the correct description, it becomes 'oily' and glossy, thinner...

To illustrate, try for yourself (or just imagine the following situation):

Get a polisher and a polish, spread it over a work area. Work it with no pressure, and fast arm speed. The 'density' of polish film may take very long time to start showing any significative change, because you're just 'spreading polish' over surface.

Now take the same setup, and exerting enough pressure, using slow arm speed, start working the section. You'll notice that in some passes (generally) 3 - 4 passes things will be slightly different, since product is demonstrating signs of use (oily, glossy, thinner... like turning transparent).

Another indicator I use to feedback my process is the easiness to remove residue at the end. If it's a breeze to remove, it may also indicates product was worked properly (not a rule, since some products may be temperature / humidity sensitive).


On same white, I've worked spots with FG400 (some RIDS) which is a white product (that may cause the issue you're relating on white), but I've used it only for enough time to remove the defects (some 3 passes with slow movement and much pressure), wiped it off and then followed with SF4000 to finish area (this for the whole cycle),

Also, I'm used to tilt my head many times closely to paint I'm working, on angle, if I have difficult seeing what's happening.

I too use plenty of light or directed light to area I'm working.

From what I can remember, many times working on white yesterday I wasn't able to see anything after some passes, just like I was 'dry polishing'. I've had this sensation 2 or 3 times, I just stopped what I was doing, tilted head on angle and after seeing the polish film there (I thought, 'nevermind') I returned and keep polishing.

From what I can recall, I had difficult removing residue on white paint when I used PBL cleansing polish. This product simply disappeared from my eyes, and I was just able to wipe it off in a efficient manner using a swirl finder light to help the task (this on a previous work on white, not yesterday).

So yes, depending on product used it may be difficult seeing on white, some more, some less.

Based on my (little) experience, SF4000 is slightly easier to work on white being it's color silver and that may contrast with white paint. PBL cleansing (which is white and goes like a cream) is tricky to observe.

Please, let me know if you got an answer,

I've done my best to help you with whatever I could on this one.

Sorry for some explanations since I'm Brazilian and I have difficult expressing my thoughts correctly in foreign language.

See for yourself, stop at every 2 words to remind how to say ......... in english?! Hahha something like that.

Again, feel free to re-question if any more help is needed.

Also looking forward to hear some other guy comments on that.

I've tried, thank you for opportunity.

Kind Regards.

[Angler]

Dear Rafael: Thank you for a very detailed explanation of how to see the product "disappear" on white paint. I now have a much better understanding of what you were describing and how to visualize it on white paint. You are telling me with white it's not so much a literal thing (the disappearance of the product)but paying attention to subtle changes in the product and that good lighting really helps.

No need to apologize about not being a native speaker of English - you do a great job of explaining yourself in English. I appreciate your willingness to help everyone on this forum and your passion for detailing. I am a big fan of your work. Thanks again!:dblthumb2:

[allenk4]

You may just have the Autopia (that Tato posted)...
confused with the one owned by PBMG: Autopia-Car-Care.

Bob


Good catch FUNX725

I forgot about the "other" Autopia


So smart....and handsome too