I got an urgent call from Dave the other day. He was in the midst of a big project and his helper was out with a bad back. Could I come and work with him for a day? His schedule was tight and he knew that I could handle whatever he had going in the spray shop.
The project he was working on involved a whole room’s worth of Art-Deco style frames/panels that were to line the walls of a home theater. Check out the photos and you will get some idea of what he was facing. His first job was to prime the frames. But that wasn’t all. Different areas of the frames were painted different colors. And, oh yes, the work was to be cut and buffed when it was done.
My job was to keep Dave in the spray booth by supplying him with frames ready for their next coat of primer. From bare wood to the completion of the primer phase, two coats were necessary. Then, the frames were to go next door to an auto body shop where an automotive color was to be sprayed on certain areas of the frames. I had to scuff sand everything twice so that things would be ready for that step.
Each frame had 19 different surfaces that needed to be scuffed. If you look at the photo of the frame with the yellow tape, if you count, you will see that there are more than 19 surfaces. Some of the work had already been done. Certain areas were covered with paper which would be cut away after the final color coat. Then, the whole frame would be clear coated prior to the cut and buff.
But my job still amounted to those 19. Since cut and buff was going to be the end result, there could be no blemishes or imperfections in the preparatory coats. I had to really get things smoothed out.
Primer doesn’t always sand well. Some kinds just don’t powder up. They tend to gum up on the sandpaper. The primers that sand well often suffer from another kind of build up because there’s no way to get the powder out of the way so that the abrasive can continue to bite. You can see that from the photos of the sandpaper that I have included.
The variation in the color toward primer gray on the paper is indicative of primer powder buildup. See the finger print? That’s from my finger pressing hard enough to make the powder stick to the sand paper. It’s hard to avoid that when you have to finger sand! If this were baseball, the count would now be 2 and 0 and I need a new bat.
The answer was Abranet. Designed for machine use, Abranet is an abrasive on a net backing. Unlike sandpaper that traps the sanding powder, Abranet lets wood powder go right through. It’s wonderful on a DA with dust extraction.
The net gives the abrasive better contact with the work surface. More cutting occurs and, because there's less powder build up, there is less friction and heat. The abrasive stays sharper longer and the absence of heat keeps the coating cool, hard, more susceptible to the cutting action of the abrasive, and less susceptible to thermo-plastic softening and gumming. Crack! The ball and bat make contact.
I use Abranet all the time on my random orbital sanders. I think 320P is the bomb for scuff sanding my seal coat. I can zip across flat surfaces very quickly and have a silky smooth surface for my finish coat. But here, in confines spaces, I used the disk without the sander. Again, I was finger sanding all of these small surfaces. I took the disk and folded it in half so that it fit better in my hand. The double thickness also gave me more stiffness and spread out the pressure from my fingers.
I learned something important rather quickly. Being a net, the direction that I folded the disk made a difference. If I folded the disk so that the strands in the net ran parallel to the direction I was sanding, I wore grooves into the primer as I sanded. Those little grooves corresponded to the grain of the netting. Look at the photos again and note that a lot of what I was sanding was small surfaces abutting an inside corner. Lots of opportunity for groovy creations running “with the grain.” That’s because the strands of the netting are not interwoven. One set of strands is laid on top of the layer below.
Again, the answer was simple. I just folded the disk so that the netting in contact with the primer ran perpendicular to the direction I was sanding. Bang! No more grooves…just silky smoothness.
Dave sprayed. Bernie scuffed. We got the project done before the end of the day. The next day, the frames went to the body shop. When done there, they came back to Dave. He used a razor blade to remove the masking and began to apply his clear coat.
As you can imagine, this was no simple, everyday finishing project. Not every shop would be willing or able to take on projects such as this. Even less would be able to spray a gloss finish “off the gun” and have it turn out glossy enough to satisfy. Fewer yet, would be willing to cut and buff these bad boys to a mirror finish. But that’s what the customer wanted and that’s the level of work that comes from the shop where Dave works.
I was pleased that they trusted me enough to call me in to pinch hit for them in an hour of need. Thanks guys for letting me help you hit a home run.
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