David Werkheiser said:
Very good article Scott, I have been following your blog for the past few years.
When you are sanding with the RO 90 on old work to mostly bare wood do you use rotex for all grits up to final grit than switch to random orbit on just the final grit, or do you switch between rotex and R/O on all grits. Also what is your final grit with work that will be brush prime/painted?
thank you, David
Thanks David, I appreciate that.
Thats a very good question. And I'll preface my answer by saying that there are many schools of thought on this, and the only one that matters is mine! Kidding, but in reality, you could ask 10 different pro or expert level users and get 10 different answers based on the types of tasks that they do. Some guys never leave the bench top, and that is a very controlled environment. Professionally, I tend to have to run tools six ways to sunday in all sorts of odd situations, but also have to know them at the spray shop level where inspection is microscopic.
With the 90, I am sanding smaller stuff. I try to size the sander closely to the task, so the 90 comes up a lot for dirty jobs like strip sanding of siding (in my area, 3 1/2" reveal is common) or sanding out exterior spindle and rail systems on decks.
When I sand that deeply on those type of items I am not very concerned about swirls because the primers and paints (latexes) have such build qualities that they will fill any minor swirling in the surfaces of those items. So I might tag out with orbital on the final grit step if I was concerned, but its rare. The bigger concern is to make sure I haven't scalloped or dished out anything, because my products won't fill those mistakes.
Generally, for all Rotexes, if I am using a Rotex sander, I am almost 100% of the time using it in gear driven mode. It would be fine with me if they didn't have orbital modes.
Grit steps vary with the task. On exterior sanding tasks, I usually stop by 120 or 150 unless it is a formal entry door (which get more coats and want to be extremely smooth and hard). I stay in the mid grits for the most part on exterior tasks because I am looking for maximum adhesion.
On interior stuff, it would be higher. Across the board for general interior tasks probably not higher than 320 unless it is cabinet grade or wood countertop type of stuff. So trim probably 320 max, walls 220. Cabinets, case by case and high. We hardly ever use the RO90 on interior work, by the way, except for the occasional need for Delta.
And, since I haven't had a chance (and probably don't dare) to chime in on the other 90 thread that is currently happening on the fog, I will say here that I don't find the RO90 to be an excessively hot running tool. We wouldn't want our hands to get cold while sanding, that would be bad for circulation... [big grin]
