Watch Autogeek's PC vidoes, the DVD and keep on reading

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Just slow overlapping passes is your best bet. Don't be afraid to turn the speed up to #6. The PC is essentialy fool proof and won't damage the paint. Moving the machine left and right, up and down, and corner to corner is the best way to remove swirls. This way every angle of the swirls are taken down. Read the direction on the polish and also read how people use it. So many times (it isn't funny) people use a product wrong or use the wrong product and say it's the products fault whereas it was all user error.
There are hundreds of products out there that'll produce results. Some people like DP, Poorboys, Zaino, Duragloss, Wolfgang, Optimum, etc. but in the end it's all user preference. The slickest finish that I have found was with using Four Star Ultimate Paint Protection (UPP).
Below are pictures of the results that could come from using a PC. Granted the swirls aren't horrible in this picutre the results are nice. The PC can handle some tough stuff when used with the right pad and product combo. I used Poorboys SSR2.5, SSR1, topped with Wolfgang Sealant.
As for time, you can expect anywhere from 4-6 hours for a full detail inside and out. Sometimes it may be quicker or longer. IT all depends from car to car. The pricing varies as well. $120-$200 seem to be average full detail prices. You could set a dollar amount per hour and base your prices on that as well. I think the average rate is anywhere between $25-60 an hour... depending on the work, area, etc. Hope this helped!!
Other results from PC work: