I just realize something...when using a PC for polishing...how do you know how much pressure to press down on the head of the machine?
I have been kinda pressing it down hard figuring the more pressure the more bite..but recently I noticed that if I back off on the pressure...I can see the pad rotating in a circular motion (which I know it is not)...
so is that how you are suppose to use the PC correctly? just enough pressure so that it looks like it is rotating in a circular motion? or the harder you press down the more bite to remove swirls?
I am sure this has been asked before...but I wanted to get the latest and fresh responses.
With my G110 I tend to use a moderate amount of pressure, not too hard not too soft on it. But I generally use 15-20lbs of pressure when trying to remove swirls
I make sure the pad is actually rotating and not just vibrating by using a black sharpie marker and making a line on the back of the pad.
There is no set rule of thumb for the amount of pressure to use because there is a lot of variables to account for. A good rule of thumb to begin with is around 10 to 15 pounds of pressure. But it is far better to look at the rotation or spinning of the pad. You want to use enough pressure to cause the pad to slow, but not enough to stall it.
A random orbital polisher like the Porter Cable works by moving the pad in a tight orbital motion. If you think how the earth revolves around the sun, the center of the pad is revolving around the center of the machine. Only the the Earth's orbit is elliptical where as the PC is a perfect circle. The tight orbit of the pad causes it to spin do to centripetal force. There is no direct connection between the spinning of the pad and the motor.
Using a dry polish (less lubrication), a larger pad, or a softer,higher grip pad can all slow the rotation of the machine, as can buffing on a tight angle or high point. To get the best results you want to keep the pad rotating at least 3-5 times per second. How do you determine this? I like to take a marker and draw a line on the backing plate, so I can track the rotation.
I have been kinda pressing it down hard figuring the more pressure the more bite..but recently I noticed that if I back off on the pressure...I can see the pad rotating in a circular motion (which I know it is not)...
so is that how you are suppose to use the PC correctly?
Both actually. Think of it as a bell curve with pad rotation (light pressure) on one end and absolute crazy pressure/ball stalling on the other end. The goal is to find that sweet spot in the middle that gives not only the best cut but also the nicest finish possible. On most paints, with most polishes, and most pads, between ten to fifteen pounds is going to give you the best starting point. To find out how much ten to fifteen is, put your backing plate on the machine and press downward on a bathroom scale.
Let's say you go to polish a section of your hood using about fifteen pounds of pressure. Polish a small test section, about 2 x 2 and inspect the finish in bright light. Are you happy with the amount of swirls and defects removed? If not, try again, this time using more pressure, and inspect the results? Did this give you the best finish possible? Do not be afraid to experiment or adjust your technique to get the best results. Paint polishing is very dynamic!
By the same token, if you get great results on your first shot, then stick with that process.
I am sure this has been asked before...but I wanted to get the latest and fresh responses.
I hope I helped, I wanted to avoid giving you generic answers or the traditioanl use x amount of pressure answer. 15 lbs is a great starting point, but keep the pad spinning and don't be afraid to alter the pressure to suite your style or the paint's needs.
You guys got my questions covered. Gracias amigos:thumbup:
I knew I was making a rookie mistake thinking that by applying more pressure it would yield better results.... I have been applying too much pressure most of the time on the pad to the point that I don't see the pad rotating in a complete circle...thus not using the the PC to it's full potential.
Marking the pad with sharpie pen is a great idea...as well as using the bathroom scale to gauge the pressure to be applied.
We got some great people who are knowledgeable as well as helpful here.
Very great community to be part of.
