In my last post, we talked about the risks of rushing a stain and/or finish job. In my job helping contractors with issues they encounter, I find that the problem with rushing sometimes starts even before the stain or finish: They take shortcuts with their sanding sequence—with disastrous results.
There are a couple examples that stick out in my mind. One contractor called me and claimed that our penetrating finish (what most people in the industry call our stain) caused swirls on his floor. He was mad! After talking with him, I explained the most common cause for swirls is improper sanding sequence or stopping at too low of a grit. He told me he had stopped at 60 with his edger and that he had 20 years of experience, but he had never seen this before. He then explained that he had only done natural jobs up to this point in his career. I encouraged him to get proper training on his sanding technique to have future success with our products.
That call is a perfect example of how stain highlights your sanding job. Sanding practices you can get away with on a natural floor suddenly look terrible under the magnifying lens that is stain. Bad big machine technique, bad edger technique, bad buffing … you can see issues with any step in the sanding once you put stain on the floor.
On another call, a guy called and said the stain itself was bad because it was lighter around the edges than it was in the middle — what most people in the industry call a "halo". He said he had 20 years of experience and had never seen that before. I talked with him about his process, and he had stopped with the big machine at 60 but edged the floor with 100. Haloing is typically caused by the edges being sanded smoother than the middle, as it was in this scenario, although even with the same grit, you can get a halo due to the difference in the movement of a spinning disc and a belt.
Even when you aren't staining, taking shortcuts on a sanding job can create problems aside from just aesthetics, including premature wear of the finish. If you skip too many grits in your sanding sequence, you leave peaks and valleys in your floor, and there isn't enough finish on the peaks. No matter what, sooner or later, most pros learn that taking shortcuts with sanding just isn't worth it.