frankosmusica
09-01-2011, 02:27 AM
I have a Dewalt 849 polisher I want to polish my own car, So I went and bought polishing compound medium scratch one and the three buffing pads. The cutting,poolishing, and finishing. Can paint really be burnt ? Ive heard many opinions many say if you stay on the same spot for a long time, some say not really if you have it in low RPM anywhere from 1000 to 1800. How good is a Porter Cable 7424 compared to the Dewalt 849 ? I heard the Porter Cable 7424 polisher is so safe that you can never burn paint with that one because of the way it spins ? This is what the guys from an auto detailing store told me how true is this ?
Blackthornone
09-01-2011, 07:53 AM
I have a Dewalt 849 polisher I want to polish my own car, So I went and bought polishing compound medium scratch one and the three buffing pads. The cutting,poolishing, and finishing. Can paint really be burnt ? Ive heard many opinions many say if you stay on the same spot for a long time, some say not really if you have it in low RPM anywhere from 1000 to 1800. How good is a Porter Cable 7424 compared to the Dewalt 849 ? I heard the Porter Cable 7424 polisher is so safe that you can never burn paint with that one because of the way it spins ? This is what the guys from an auto detailing store told me how true is this ?
You can burn paint, that is , polish through to primer or bare metal with ANY polisher, even a DA, if you stay on one area long enough. The Dewalt 849 is a rotary, I believe, which means that it is particularly prone to burning paint if you stay on one spot for too long, at too high an RPM, particularly on an edge. It all depends upon how much heat you generate on one spot. If it gets hot, you are in danger of burning paint. If it gets barely warm, you probably won`t, unless it is a raised edge, in which case the amount of friction will be concentrated on a very small area, thus resulting in much more heat generated there. However, with enough practice, you can use a rotary on almost anything safely, provided that you stay away from, or protect edges and raised ridges with masking tape adequately.
Best to practice on junk parts to get a feel for how far you can push it in order to polish fast without burning paint. However, if you stay away from edges, use a low speed, hold the buffer properly, and keep it moving in a uniform pattern to ensure more uniform polishing, while erring on the side of caution instead of going for speed, you should be able to do your own car without incident. You must be extremely careful and cautious however, and have good control of the machine. That of course, is key, because damage can be done if it gets away from you or you apply too much rpm in one place because you aren`t used to it yet. However, this is all if you have a knack for using power tools. If you are totally inexperienced with power tools however, you need to practice on junk panels. Visit your local bodyshop to see what you can dig up, or a junkyard.
It would be best to get hands on training to use a rotary.
I do not recommend that you use a rotary on anything that you care about until you have enough experience to be sure you know how to use it properly.
You can burn through paint down to bare metal in less than a minute with a rotary.
The Porter Cable 7424 is an orbital buffer that is the safest type for a beginner to use. It`s random orbital oscillation pattern of buffing reduces the amount of heat concentrated in one area at a time, and prevents hologramming.
You can burn paint with either tool.
Random orbitial: takes deliberate action to burn paint.
Rotary: a momentary lapse of attention causes hundreds of dollars of damage.