Rotary vs. PC for Finishing Polish

wannafbody said:
i think it's the throw of the pc producing the small gashes when a product hasn't fully broken down.
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That's exactly it; the paint hardness will determine how easily you get this marring, and how prevelant it is. On G35s for example (I know, I know), there are two ways I can finish down; either 106ff/grey via PC @ LOW speed, super slow passes or via rotary... Obviously I choose rotary - the paint is just so soft with the PC almost everything leaves marring.



On the other hand harder paint you can finish doen perfectly clear with the PC. Just have to get a feel for the paint.
 
I find that any polish that needs breaking down requires speed 6 with a 6" pad. Anything short and the abrasives never break down.



Spread on speed 5, polish on speed 6, then finish with speed 5.
 
Picus said:
That's exactly it; the paint hardness will determine how easily you get this marring, and how prevelant it is. On G35s for example (I know, I know), there are two ways I can finish down; either 106ff/grey via PC @ LOW speed, super slow passes or via rotary... Obviously I choose rotary - the paint is just so soft with the PC almost everything leaves marring.



On the other hand harder paint you can finish doen perfectly clear with the PC. Just have to get a feel for the paint.
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Bingo!! That's the way you do it with soft dark paint. As far as SSR polishes making those marks, I don't think so because SSR1 and an LC finishing pad is the one I use to clear up soft dark paint.
 
RAG said:
Actually, I'll bet money he's done this...I know I have...and that's when the micro-marring is most niticable. If David replies, I'll bet he'll confirm that the micromarring is millions of little 1/8" lines with a slight curve to them (following the motion of the DA).
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Sorry, yes - the micromarring is the small 1/8" line with slight curvature, best shown actually in Brazo's pic of the blue Clio door. Metallic flake does an excellent job of hiding these marks, indeed with a strong flake, you wont notice them. On a flat colout though, they are clear under the right lighting conditions and the rotary doesn't induce the micromarring.



Also as mentioned above, the paint hardness will also have a significant effect on the enmd resutls has well. Nowadays however, and I started off my detailing with the PC, I very rarely use it for anything other than applying glazes and sealents as I can just get a far sharper LSP ready finish from the rotary, even on the soft as swiss cheese Honda paints we get in the UK.
 
RAG said:
This micromarring doesn't always occur, as it very much depends on the paint hardness and color, as well as polish and pad selection...not to mention pressure and technique. But on really dark colors it happens often.
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Color has nothing to do with the marring, just our ability to see it. If you're marring a black car, all things being equal, you're gonna mar a white car.



A few people have said it already, the marring you speak of is from not being able to properly break down the polish either because of poor product/pad selection or from not working the polish long enough.



That doesn't mean that a rotary produces a finer finish. If that were the case you would see rotaries, not DA's, in the hands of the people polishing cars coming off of assembly lines.
 
I still believe now that DAs are just not as capable as rotaries at fully breaking down a polish owing to the motion of the pad - the jiggling or oscillation will result in a less even break down of abbrassives than on a rotary and this I believe goes a long way to the improvement in clarity of finish that you get when using a rotary over a DA. DAs remain very popular in the UK, but mainly as a beginners tool as they are safer than the rotary, but the pros remain on the rotaries as this is how they believe they achieve the best finish.



As a hobbyist detailer, who started out on the PC, I now also believe that with the rotary I can achieve a superior finish than I could from the DA.
 
Bence said:
How does a forced rotation DA like the Mak BO6040 fit into this picture?
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The DA mode on that machine is much stronger then a PC. No bogging at all. It definitely makes it easier to break down polishes.



I can't comment on the finish that the forced rotation mode leaves as I haven't tested it extensively enough. I use a rotary for correction or use the forced rotation mode for a quick spot repair and then go right to the DA mode to finish.
 
Wouldn't the problem come primarily from the initial bite of the polish? So couldn't you just use a milder product?



Heh heh, this thread has me thankful that most of our vehicles have reasonably hard clear, but my Jag's ss lacquer is *soft* yet I don't get the little hook-like marks when I use the PC on it.



And what is it with those blue Audi A/S4s? I sure hear a *lot* about their paint being so soft :nixweiss Mike Phillips finally resorted to #66/PC/9006 on the last one he did, anything else left micromarring (note he didn't finish up with a rotary).
 
Accumulator said:
And what is it with those blue Audi A/S4s? I sure hear a *lot* about their paint being so soft :nixweiss Mike Phillips finally resorted to #66/PC/9006 on the last one he did, anything else left micromarring (note he didn't finish up with a rotary).
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Really??! In the UK, all VAG cars have a well deserved reputation for solid as a rock paint! Took me three days in my PC days to do a badly swirled A4!!! Power Gloss and IP needed...
 
I wonder if it depends on the blue color (seems weird, since they are cleared), the audi's ive done this summer (sprint blue) were both harder than average.
 
Heh heh, yeah, I sure know from hard Audi clear, but IIRC the Nagaro (sp?) ones are especially prone to being soft :nixweiss
 
SpoiledMan said:
A rotary will finish brighter and clearer than a PC. The Cyclo comes really close to the rotary in this respect. Finishing with the rotary and not having any trails? Lots of practice!
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that depends.



You may spend 3 hrs with a rotary, but what if I spend 6-7 hours with a PC? it all comes down to technique and prepwork. Rotary to me is if you do it professionally and need the job done faster. I like DA polisheres such as the PC and Cyclo for their safety. Alls it takes is one slight mess up and or destraction, and you could be paying for some paint.



Thats just me tho..
 
It's something you'll need to see in person. There's a definite difference between the two in how nice and bright/clear they finish. The PC simply can't duplicate that.
 
LIke every tool box, there is a place for each. There is a reason for the two types, even 3rd and 4th types if you consider cyclo and forced rotation.



What i comes down to is knowing what is the best tool for that instance. Sometimes for some people it will nearly allways be rotary, for others nearly allways portercable da. For others it's the phone when they call us...
 
Picus said:
That's exactly it; the paint hardness will determine how easily you get this marring, and how prevelant it is. On G35s for example (I know, I know), there are two ways I can finish down; either 106ff/grey via PC @ LOW speed, super slow passes or via rotary... Obviously I choose rotary - the paint is just so soft with the PC almost everything leaves marring.



On the other hand harder paint you can finish doen perfectly clear with the PC. Just have to get a feel for the paint.
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Does having the pc set on a lower speed affect the micormarring - I haven't done this experimen yet?



And in response to a few of the other posts - on darker colored cars...especially black...I usually get this micormarring with the PC...and I've tried about 10 different final finishing polishes with several different pads...and I've even worked the polish for ridicolous amounts of time - It's just gonna happen on some paints (more "noticable" on dark colors). This is the whole reason I forced myself to learn to finish down with a rotary on black (halogram free)...and its worked.
 
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