Can anyone offer suggestions as to grit and sequence for sanding frame and panel doors on a widebelt sander? The joints are cope and stick that are fairly flush, starting with material surfaced to 7/8", in common species. The sander is a Ramco with a contact roller only (75 durometer). I realize I will need to dynabrade sand to remove the final crossgrain scratches. What grits are appropriate to finish the back as well as the face in different species? I have previously sanded my doors with a PC belt sander and dynabrade orbital.
From contributor R:
We start with 80 grit paper and take one or two passes as required, then 120 to150 grit and then to the dynabrade table for final face sanding and edge easing.
We use the following guidelines for grits and depth of pass:
80 - .015
100 - .010
120> - .005
Of course these are guidelines. You can take more off with narrower material, maybe less with wider material. We have an ammeter to help us determine the load.
And then there are some species, like maple, that will burn if you walk past it too fast. Light passes work for us.
For RP doors, our framestock is 13/16” thick. I’ll just list out here the face, grit, and thickness setting.
Back 100 .800”
Back 100 .790“
Front 100 .780”
Front 100 .770”
By this stage all joints should be smooth; if not you need to look at your shaper setup.
Front 120 .760”
Back 120 .750”
At this stage our door is actually ¾” thick, so we would put the edge profile on it. We were using Voorwood’s Turbo Sand system and it worked best that we had ¾” doors before we profiled and sanded the profiles.
Back to the widebelt:
Back 180 w/platen
I would set the platen here and just lower it about .005” with each pass from here.
Front 180 w/platen
Front 220 w/platen
Back 220 w/platen
Back 240 w/platen
Front 240 w/platen
When doing cherry or hard maple, stop at 220, as both species tend to glaze over and make staining a bigger hassle than it already is. Also, when doing solid wood doors, i.e., no cross sand marks, we would stop at 180. I don’t know of many people who go all the way to 240, but for us the main thing was it took very little to clean it up with an orbital. I figured it was faster and easier to run the doors through the widebelt another pass versus the extra time it would take with an orbital. For what it's worth, we sanded all solid wood with 180 grit 5” Stik-its and all veneer with 220 grit 5” Stik-its, specifically 3M’s Tri-M-Ite, a Silicon Carbide abrasive. On our widebelts we used 3M’s Aluminum Oxide abrasive, Three-M-Ite. For the 100 and lower grits I used the Y weight cloth with the anti-static coating. For the 120+ grits I used X weight cloth again with the anti-static coating. For 180+ you can look into using paper backed belts, but the problem I had with them was they would tear when taken on and off the machine. I never really had an issue with the durability of them. I am mentioning brand names here because it took me a fair amount of time to come up with this system, and it worked flawlessly for us. 3M also spent a fair amount of time here helping me through this. Yes, there are cheaper products out there, but the support I got from 3M was more than I could have asked for, and I feel like specifically 3M’s products were integral to our process.
Once you come up with a system that works for you, follow it. Saving five minutes on the widebelt suddenly doesn’t look so good when you’ve got a bunch of doors that have to be refinished.