View Full Version : Pictures from May 7, 2016 Advanced Class

Michael Stoops
May 9th, 2016, 07:20 AM
More wet sanding and rotary polishing!!!

Following the usual classroom instruction and a quick lunch, we head out to the garage for some hands on demos and then let the guys get to work with their new found knowledge. We start off with proper hand sanding techniques. You can see that we have a foam backing pad that the sand paper is wrapped around. This gives us a uniform contact between abrasive and paint.

Here you can see the very close spacing of the individual strokes used when hand sanding. All too often we see people really spread out those strokes, and that leads to very uneven sanding.

Here's an example of what you do NOT want to do! Those four straight lines are sanding marks created when we removed the foam pad and just used our bare hand with the sandpaper. Your fingers will create pressure points, and the spaces between your fingers will put almost zero pressure down on the paint. Obviously this leads to some real problems!!

Hand sanding an edge calls for some alterations to technique. Here, since there is a roughly 5/8" lip on the edge of the panel, we lift part of the foam pad away from the paint so as not to put unwanted pressure on the high spot of the lip. To be totally candid, if this were a real world project on an actual car, we would quite literally cut down one of the foam pads to fit the width of this lip and sand it that way. Barring that, however, we can adapt our technique and work this tight area in a safe manner.

DA sanding is a whole different game. We can cover large areas very quickly, and we can match texture in the paint if needed by utilizing the Unigrit Finishing Discs and foam interface pad.


Even the contours on this hood can be addressed with a DA sander. Here we approach the scalloped contour from one side, allowing the foam interface pad to conform to the curve and support the abrasive disc.

Later we come back the contour from the other side to finish it all off. You can see that we don't actually run the abrasive disc over the hard edge at the top of the contour - we don't want all that pressure centered on a high spot! We can easily come back with a quick pass over the edge if need be, using extremely light pressure on the DA sander, or by hand with very light pressure.

On the far left side, where the paint is totally dull and there is virtually zero reflection, we sanded with 1500 grit via DA sander. To the right of that (you can just see the student's head reflecting in the paint) we followed up with 3000 grit to refine the surface and actually started picking up some gloss. The smaller area to the far right was hand sanded using 1000 grit followed by 2500 grit.

With the sanding done it was time to introduce the guys to the rotary polisher. Here we're using M105 on a burgundy foam cutting pad.

The tighter contours that we sanded earlier are most easily compounded with a wool pad for sanding mark removal. This is one of the areas of potential danger with a rotary if you're not used to the tool. The outer edge of the pad moves with the greatest velocity and therefore with the most aggression. A foam cutting pad, with the edge completely dry and void of product, will burn the tight radius curve almost immediately. A wool pad is far more forgiving here, and much easier for a novice user to come to grips with.

OK, time to let the guys cut loose and see what they've learned!

We are always on hand for direct guidance throughout the process.

"Here, you sand and I'll buff" Yep, teamwork!



Hmmm..... look at the techniques here. Think they might have learned from the same instructor?!?!?!?

Late in the day, just for giggles (well, and to demonstrate what's happened in the real world of detailing in recent years) we set aside the rotary and picked up an MT300 dual action polisher. After hand sanding with 1000 grit and following up with 2500 grit, we mounted a microfiber cutting disc to the MT300, primed it with M100, set the tool to 5800 OPM and went at it. In extremely short order the sanding marks were gone and the paint looked fantastic. DA polishing technology has come a very long way in the past few years - high torque DA tools like the MT300; microfiber discs that carry very large abrasive loads to the paint and add their own high level of cut; SMAT abrasive compounds like M105, M101 and M105 that provide very high levels of cut with a great finish at the same time. Put all that together and we see fewer and fewer detailers using rotary polishers in their day to day operations. Sure, there is still a time and place for the rotary, and some people have just become so expert with them that they can't walk away from them - that's all fine, great actually! But don't dismiss the potential of a powerful DA tool, especially when coupled with the right pad and liquid.

May 9th, 2016, 07:18 PM
Fantastic post with great pics!