After all the tedious stripping, bodywork, primer-blocking, and then laying down the paint, the true reward is only gained after the cut and polish is completed. In the old days, the process was called burnishing, and it meant taking an abrasive to a surface until perfectly smooth and flat, and then polishing it to a mirror finish. In the world of custom automotive finishes, the cut and polish job is the route to those show-stopping paint finishes that are the envy of all.
Although it takes considerable skill to achieve a beautifully polished paint finish, it's a skill that can be quickly mastered by those willing to put in the effort. The list of equipment required is relatively short, with the only specialized item being the paint buffer itself. As the terminology implies, a cut-and-polish effort is really two separate tasks, the first being to sand the freshly cured paint, followed by the polishing process.
It might seem drastic to take sandpaper to that gleaming fresh paint, but that's just how the job begins--with wet-sanding of the surface. Specialty sandpaper of a very fine grit is used, which creates sanding scratches of minimal depth so that they can be polished out in the buffing process. There's no question that a variety of paint sins can be improved by the cut-and-polish process, but it holds true that the better the quality of the finish "off-the-gun," the better the final results. Ideally, we would recommend the finest paper practical for the sanding process, but if the finish is showing fairly heavy texture, or "orange-peel," beginning with a coarser paper may be the only practical choice. Generally speaking, 1,000 grit is the coarsest normally used for wet-sanding the finish, while 1,500 is the norm, and as fine as 2,000 grit is preferred by some.
Clockwise from the lower left are the supplies required to cut and buff a paint job like a
During the sanding process, it's important to keep the surface wet and cleared of sanding debris. An ample supply of water is required, most commonly supplied by a large sponge and bucket. Use a small amount of dish soap in the water to help lubricate the surface, and work the sandpaper in long, consistent strokes. To improve leveling, it's advisable to use a flexible hand pad, or block, to back up the sandpaper, rather than working the surface by hand. The objective is to get a perfectly smooth and flat surface, devoid of any gloss. It's impossible to tell if the paint is sufficiently sanded while the surface is still wet since the water will impart a false gloss to the paint. The procedure is to sand, wipe dry, and check, and then sand some more or move on.
Polishing is the process of bringing back the luster and shine of the paint, which has been made dull by sanding. To do so the surface of the paint is evenly polished down until all the surface is below the level of the sanding scratches and perfectly smooth. Although many painters have their own favorite techniques, processes, and materials, the most common approach includes two steps: a coarse rubbing-compound cut, followed by a fine-polishing compound or glaze. The compounding cut is usually done with a coarser-texture pad on the buffer, and the objective is to remove the bulk of the sanding scratches, quickly taking the paint down to a relatively smooth shine.
The aggressive action of the compound, however, isn't fine enough for the brilliant and smooth show-car finish we're after and typically shows distinct swirl marks in the paint surface. To correct this, we have a second stage of the polishing effort. The finishing compound, or glaze, is a much finer compound and removes a minimum of paint material, while polishing the surface to a brilliant shine. Normally, a much finer polishing bonnet is used for this step. Follow along as we work through all of the cutting and polishing steps on our recently painted aftermarket L88 hood.
|Difficulty Index - 3 Wrenches|
|Anyone's Project: no tools required||1 Wrench|
|Beginner: basic tools||2 Wrenches|
|Experienced: special tools||3 Wrenches|
|Accomplished: special tools and outside help||4 Wrenches|
|Professionals Only: send this work out||5 Wrenches|
Step 1 is to cut the paint surface, usually the clear coat in a modern two-stage paint job
Clear will sand off in a white slurry, and the surface will show an evenly flat sheen with
A good buffer is mandatory to achieve good results. Unlike a sander, which operates at hig
Paint specialists seems to have their favorite brand of compounds. We like 3M brand produc
The technique is to let the operating buffer pick up the compound and spread it over the w
Edges are a special consideration since the buffer can easily catch and burn, or scrape th
Attempting to cut into an edge, as shown by the buffer position here, causes the pad to gr
Once the entire hood is compounded, it's noticeably glossier than before, though close exa
We changed pads to a Schlegel number two Buff, a fine-polishing wool pad, in preparation
Applying the glaze (polishing compound) is just like with the cutting compound, again work
The final glazing is done with much the same technique as the cutting compound, though the
This is the kind of paint finish that makes all the work seem worthwhile.