Polishing theory ?

[mpmiller37]

Based on the assumption that abrasive polishes are like liquid sandpaper, does the following theory hold true based on the abrasiveness of the products:

If I were to polish an area 3 times with #80 would that equate to polishing 1 time with say #83.

This theory is based on the assumption that each time you polish with #80 you are taking a bit more off the surface which at some point would equal the amount #83 would take off in 1 pass.

Thoughts ?

[Mike Phillips]

Re: Polishing theory ?

Originally posted by mpmiller37
Based on the assumption that abrasive polishes are like liquid sandpaper, does the following theory hold true based on the abrasiveness of the products:

Right off the bat we would disagree with your assumption. Meguiar's products are nothing like liquid sandpaper. Traditional rubbing and polishing compounds are like liquid sandpaper, not Meguiar's compounds, paint cleaners and cleaner/polishes.

Meguiar's has done more to educate people about how to remove defects without instilling defects at the same time than anyone else in this business.

One of my job is correcting misinformation so anytime someone comes onto our forum and equates our complexity and highly efficient paint cleaning products as something as simple as sand-in-water then I have to step in and do my best to steer the conversation the right direction.

I understand what you're saying, but we don't want our products compared to or represented as simple abrading products because they are much more complex than that.

If I were to polish an area 3 times with #80 would that equate to polishing 1 time with say #83.

Maybe, maybe not. Depends on variables that are not controlled such as technique, pressure, time, skill, paint hardness.

This theory is based on the assumption that each time you polish with #80 you are taking a bit more off the surface which at some point would equal the amount #83 would take off in 1 pass.

Thoughts ?

We would agree with the material removal point you make, however the finish quality may not always be the same between different products.

How's your black car's finish doing?

[mpmiller37]

Didn't mean to imply anything negative about Meg products, just trying to simplify a concept. Anyway, I understand your point.

I polished the trunk and it turned out pretty good with 2 passes of #80 and used #21 as LSP. I must be getting to picky as it still does not seem good enough :-)

If it doesn't get too cold here in MD then I may try to polish the hood over Thanksgiving.

Thanks

[Mike Phillips]

Originally posted by mpmiller37
Didn't mean to imply anything negative about Meg products, just trying to simplify a concept. Anyway, I understand your point.

Cool.

One thing I've learned about discussion forums is bad information and rumors travel fast and once they've spread it's hard to undue the damage.

I polished the trunk and it turned out pretty good with 2 passes of #80 and used #21 as LSP. I must be getting to picky as it still does not seem good enough :-)

If it doesn't get too cold here in MD then I may try to polish the hood over Thanksgiving.

Thanks

One of the things that doesn't get a lot of pixel time on this forum but is mentioned in our How To Remove Paint Defects video is the technique of [b][i]lifting-up on your polisher for you last few passes to lessen the pressure and begin doing some finesse polishing. Another option would be to re-polish the area with yet a finer polish and a new/dedicated foam polishing pad for example, after M80 re-polishing the panel with either M82 or M09, using light pressure and then applying your choice of LSP

Black is tough not because it's black, because in reality it's clear paint over black, but because the darkness of the color tends to reveal any and all defects in a way that your eyes can most easily see these defects.

It is possible to create a flawless finish on black, it just takes the right products, a little skill and patience, and the human elements of care and passion.

Maintaining a flawless finish on black is another story.

[Kevin Brown]

In terms of overall defect removal, and without consideration given to gloss of the finished product (since we all agree that a fine cleaner/polish will leave more clarity of a surface than an aggressive one...

The theory that multiple passes of a light polish equals one pass of an aggressive polish is not an accurate one (At least in terms of real-world use).

Further, you will not get the same results by using multiple applications of a fine sandpaper versus one application of an aggressive one (when comparing repairs done to two similarly defect-laden surfaces).

Relative to automotive paint, think of a surface that has heavy orange-peel... Lots of peaks and valleys. If you wanted to sand it flat (taking away the peaks), you would have to initially cut the paint deep with an aggressive sandpaper. If you used only fine paper and spent more time sanding, it would not evenly level the paint. The paper would have a tendency to ride atop the uneven surface (unless you were working only on completely flat surfaces, at which point you could use a hard block to back your sandpaper).

A similar action takes place when you are utilizing a soft pad (wool, cotton, or foam) and compound. There's a lot of give at the surface of the pad, so it'll have the ability to contour to the painted panel. On a micro-level, could you imagine minute pad movements while gliding along the painted surface? Certainly, so it is possible that the pad would not create a flat surface (which is needed to push through and abrade defects evenly (when used with an abrasive compound or polish).
To eliminate defects properly, use a more aggressive compound initially, then follow up with a milder one.

Just a thought...

[RDVT4ME]

Mike,

You bring up a great point on making your final passes with little pressure to allow the diminishing abrasives to work their best. I suspect that's where a lot of rotary users get in trouble.

[Mike Phillips]

Originally posted by Kevin Brown
[BTo eliminate defects properly, use a more aggressive compound initially, then follow up with a milder one.

Just a thought... [/B]

And a very good thought!

Your post was insightful, just one thing we have to remember when speaking about and thinking about Meguiar's diminishing abrasives that would bring to this discussion a different aspect than a coarse sandpaper as compared to a fine sandpaper is that even though with Meguiar's compounds, paint cleaners, and cleaner/polishes you may start out with an aggressive abrasive, if properly worked against the finish you end up with nothing, that is our diminishing abrasives pulverize into nothingness. That doesn't hold true for the abrasives used to make sanding papers.

At the same time, as Kevin has so eloquently pointed out, best results, and in some cases your fastest results will come from correctly choosing a more aggressive product but following up by using a less aggressive product and in some cases following up with a couple of less aggressive products and/or pad combinations as well as switching from one tool to a different tool to change the action of the polishing process, i.e. switching from a rotary buffer to a dual action polisher.

Thus polishing paint is not a process, but correctly done an art form that requires not only the right products, tools, skills and experience, but even deeper things such s the human elements of care and passion.

[gb387]

Originally posted by RDVT4ME
Mike,

You bring up a great point on making your final passes with little pressure to allow the diminishing abrasives to work their best. I suspect that's where a lot of rotary users get in trouble.

Would this same idea apply with a PC?

[Mike Phillips]

Originally posted by gb387
Would this same idea apply with a PC?

Most definitely, it would even apply to your hand.