We are going to be using primarily waterbornes and intend on doing the initial, more intensive (grain raise) sanding in an area set up for this in our shop. Our questions are:
1. Does it make sense to scuff between coats in the booth while ventilating? Is the minimal dust created problematic? Could it create more static electricity within the booth? We are going to use an Ionix blow-off gun in the booth
2. What is recommended for wiping off the part before shooting? Should the rag/cloth/wipe be wet?
3. For inter-coat adhesion with waterbornes would something like the 3M nylon Brillo type flexible abrasives work, or is paper required? Can the rule be generalized here or is the application specific to each manufacturer?
From contributor J:
Those are great questions. Here are the procedures I use. If there's a set-up, I roll a vacuum to the areas where the sanding is taking place. Any time you create dust, it has a couple of areas that are not great for finishing. The first is obviously in the finish coats being applied. The second is that the it's collecting on the intake filters, which restricts proper air flow. I have also found that the Micro-pocket rags sold at the home improvement store to be a real good replacement for tack rags.
Once the booth and pieces have gone through a couple thorough sweeps to remove dust and boulders, I tack 1-3 times with a very light spray of denatured alcohol on a clean pocket rag. Denatured alcohol also helps to remove static charges on surfaces. Also, keep in mind that anytime you rub or cause friction on a surface, you cause the piece to become magnetized. This is more noticeable when the humidity is low and heat is high, such as winter inside our shops.
I also use the Scotch-Brite maroon pads to scuff my glazing jobs and for final coat prepping. I feel it is adequate for inter-coat adhesion purposes. Finally, if you are sanding in the booth it's better to have the fan on than off so that the dust doesn't attach itself onto the ceiling and drop down on the final coat.