3m..circle or back and fourth

N

na2c32

New member
i just purchased both 3m smr and fine cut compound..on the back the instructions say to apply in a circular motion until dry..however isnt it suppose to be a back and fourth motion? thanks!
 
in my experience, be it circular or back and fourth motion, i wasn't able to cut on the paint by hand with these SMR and fine cut. this is better suited to a rotary i guess...



just my experience...
 
I don't buy the whole "front-back motion" argument. PCs don't go front-back and nobody says *they* cause any problems. The whole idea of going front-back is that *IF* you cause marring the straight scratches will be less noticeable. But you shouldn't cause marring anyhow. The only time I go front-back is when I'm working on a single isolated scratch by hand and want to limit the area being worked. I honestly think that I'd have noticed by now if there were some problem related to going in circles ;)
 
Slightly different take than Accum.....I would be comfortable doing circular the first time around if trying to remove swirls. Your trying to eliminate or reduce swirl patterns. Of course you would yield better results using a PC. But, after your swirls are reduced and/or eliminated, I would opt for back and forth motions/patterns to reduce the potential for further swirling. Swirl marks are more physically apparent from all angles, than a fore to aft mark.
 
na2c32 said:
i just purchased both 3m smr and fine cut compound..on the back the instructions say to apply in a circular motion until dry..however isnt it suppose to be a back and fourth motion? thanks!
Click to expand...



The whole business about straight back and forth motions is that any marring induced will be less noticible, nothing more.



Think of it this way, if a straight back and forth motion was more effective or somehow safer for paint then we would all be using something that looked like a belt sander that went back and forth rather than "rotary" buffers. :D



Use whichever motion feels more comfortable to you :xyxthumbs
 
I believe going forward and back is the correct method, in fact following the airflow of the car is in my mind when I polish and clean.



Since using the PC I still follow the airflow over the car, even though I know its a random orbit ... go figure ... hard habit to break I guess. :nixweiss
 
I always thought that looking at the imperfections in the paint and going across the grain of the scratches/swirls etc...will yield the best results
 
What makes a scratch visible is that it makes the paint surface two-dimensional and the light reflects from the microscopic peaks and valleyâ€â„¢s differently from the rest of the paint surface. When you abrade an area with a machine and a foam pad these abrasions form a uniform pattern (the machine /foam pad applies an even and consistent pressure) and light reflects from its surface evenly without any two-dimensional reflectance.



The reasoning behind hand polishing in one direction only is that unlike a machine polisher the pressure applied is not consistent, especially if you polish using circular motions. The inconsistent abraded pattern causes light to reflect unevenly thereby highlighting the abrasions.
 
On the back of AIO it says to apply in a front to back motion (because cicular motions arnt polishing)



lmao !
 
As with any product, inspect your work after a small area, and look for the results your after. I find it easier to go in circles by hand. I can apply more even pressure this way. In a straight line i could apply too much pressure, in one spot. By hand i have removed 2000 grit sand marks, with FC and SMR. In one area, any more and my arm would have fallen off. Don't expect to do the whole car by hand.
 
You must log in or register to reply here.
Back
Top