Sanding Face Frames

Cabinetmakers discuss whether to sand face frames before or after assembling them, and other fine points of sanding technique. October 2, 2007

Our company is having trouble with how many belts are getting used because of burn marks and such. After looking over a few different forums, I found that most companies sand the separate frame pieces, then assemble, then sand by hand (with an orbital usually). We do the process opposite by assembling frame first, then sending it through our wide belt Timesaver sander. What do most companies use as their flow process? When you do sand, what kind of sander and paper do you use?

Forum Responses
(Cabinetmaking Forum)
From contributor J:
We always assemble first, then sand. If you sand first you will still have to take a significant amount of time sanding joints that don't line up perfectly. We usually start with 80 grit and step down through 120, 150, and 180 with the belt sander before RO sanding with 180 and 220. We have found that if you run the face frames through the sander at a slight angle, the belts last longer because one small section of the belt isn't doing all of the work.

From contributor A:
I found that if I plane the face frame stock to a common thickness and width first, I have very little sanding at all, just a little touchup at the joints with 150.

From contributor G:
You have to sand it if you're going to finish it. 220 is excessive, though. 120-180 should be plenty for most applications.

From contributor M:
I always assemble first, then sand. If you are experiencing burning prematurely, then it sounds like your guys are taking off too much to begin with and thus shortening the life of the belt. Burning is never an issue in my shop.

From contributor T:
Our approach historically has been to build the face frame first, then run it through the widebelt. We have a 42 inch sander but every now and then we end up with a face frame too big to fit in the machine.

I personally built a couple of these big ones last week and the experience has got me to re-thinking why we do it in the sequence that we do.

The advantage of sanding parts first, then assembling, is that you don't have any cross-grain scratches to contend with. But if the primary justification for widebelt after glue-up is to flush up the joint, perhaps the real solution is to focus on producing a better joint?

From contributor O:
I sand all my face frame parts through my wide belt sander first. Assemble, then sand in one quick pass once more through the wide belt sander. Assemble the cabinet and orbital sand it with 180 grit. I'm using a rather odd wide belt sander with a low feed rate and a 7 1/2 hp motor. Sanding all the parts twice sounds strange, but I get great results and very little cross grain to speak of, since the one last pass in the widebelt isn't taking off very much, and the machine has an air platen shoe. If I get a couple of joints that need a more aggressive sanding, I grab the 3x24 belt sander and go at it. Usually it takes very little effort. If I had a decent wide belt sander, I would skip the first sanding step. Gotta work with what ya have.

From contributor B:
The problem you're describing may very well be the result of a variety of things, but perhaps this info will help. I agree with what contributor M said, that you're probably taking off too much to start. By any chance, is this a ceramic belt? With ceramic belts you're being forced to apply more and more pressure because the abrasive grain is not friable. Friability is when the abrasive grain fragments as heat and pressure are applied, creating new sharp edges. Ceramic belts will tend to get duller and duller, causing you to apply more and more pressure.

I also agree with what was said about running face frames at an angle, but it really all depends upon the belt.

From contributor D:
I just don't get it. If you use a Castle pocket screw, there is no misalignment. I build primarily beaded inset face frame cabinets. I make sure I get a good cut off of the planer. I screw them together and sand the entire face frame with 150 grit 6" random orbit. If I messed up on a joint, I might spot sand the joint with 100 real quick. I never understood why you would purposely cause cross grain scratches. If I can run a 6" random orbital down a 1 1/2" double beaded mullion with 7/8" of flat without dinging the bead, what are you concerned about?

From contributor L:
Ditto. I have seen shops that use the wide belt to sand face frames. They believe it is quicker to flatten everything. That is until the platen grabs a frame and breaks it up. Then your wide belt is down while you repair or replace belts, etc. I think the argument is that they are bringing 13/16 stock down to a uniform 3/4. Of course, these same shops plane their face frame stock to whatever standard width they are using.

I suggest getting away from the widebelt altogether. Instead, when you are planing your stock to width, go ahead and plane to finish thickness. Assemble your frames and hit them with the ROS. Much faster and more consistent. Use the widebelt for more productive processes.

From contributor J:
I am curious, if you have a wide belt sander that you don't use for face frames, what are your "more productive processes" that you are using it for? I am not trying to be combative, but I am honestly curious what people are using their wide belts for if they don't sand their face frames with it (and don't build their own doors).

From contributor O:
Other things to use the wide belt for if you're ordering your doors, and not sanding face frames:

Pre-sand face frame parts.
Sand one piece drawer fronts (door company takes too long to deliver).
Sand base shoe and scribe mouldings.
Glue ups (like corbels, wood tops, large drawer fronts).
And face frames, again, when the Castle face frame joints slip a little in the shop-made face frame table.

We have a stroke sander also; can't live without it.

From contributor O:
Also end panels. (We build doors.)

From contributor R:
I had that problem years back. Let your glued up face frames and doors dry longer - it's just glue clogging up the paper. Remove the belt and bend it sharply and the glue will show itself. Your fingernail will remove it like pulling scabs from a sore. Any clamping system and any angle pocket screw needs to be sanded to some degree. I would think the only reason that anyone is not running his face frame through a wide belt is because he doesn't have a wide belt.

From contributor V:
I think contributor R is on the right trail. I have that happen from time to time. I sand desk tops and stuff like that, but I don't think it's just drying time. I have started taking the random orbit to my panels and tops and sanding off the glue before I run them through the sander to solve the problem.