Should a Widebelt Sander Have a Platen?

Some thoughts on what a widebelt sander's platen contributes to performance. June 16, 2014

Question (WOODWEB Member) :
Is it absolutely necessary to have a platen on a wide belt? I am sure it is but I have a drum sander now and moving up to a wide belt even without a platen is probably going to make a big difference. If I sand doors up to 180 grit will I still get a good finish or will I still have to orbital the doors like crazy like I do now?

Forum Responses
(Cabinetmaking Forum)
From contributor L:
A platen for the last, fine pass (only) will improve the finish but you will still have cross grain scratches. Meaning unless you want to compete at the bottom of the barrel, you will need to orbit sand. The Viet sanders with the big, soft, third head do a better job than most for near/good-enough finish sanding.

From contributor M:
You will always have crossgrains from widebelt even with the platen. I rarely use my platen so I don't think itís a must. But, if you're spending the money anyway get one for sure.

From contributor D:
220 grit w/platen makes your orbit sanding quick and easy.

From the original questioner:
The reason I ask is that I can get a 42 " Rand-Bright for a good price and it is in excellent shape, but it does not have a platen. Itís 25hp electronic tracking but Iím hesitant because there is no platen. The machine has had light use and will still last a long time. Should I do it anyway?

From contributor F:
I don't have a platen on my machine and manage to scrape by anyway. Would it be a nice accessory to have - sure! If it's a good machine with a large drum I think you'll be ok.

From contributor L:
Probably not having a combination head means it has a larger diameter drum. The larger the drum the better the sanding action, all else being equal. Also, on single head machines they usually use a softer durometer which has its good points and bad. It will produce a better finish sand but dub the edges more, that often doesn't matter though. Even without the platen you will be much better off with a widebelt than a drum sander. Itís low cost enough that you can always sell and move up.

From the original questioner:
Iím going to do it! This is kind of what I figured anyhow. Itís going to change my life considerably with or without a platen.

From contributor R:
A platen is what separates a drum sander from a wide belt sander. The next step up is a stroke sander. From there you can go straight to finishing. Most folks don't even know what a stroke sander is and can do. Many consider them obsolete. In one shop we had a wide belt and three stroke sanders. Even metal shops can use stroke sanders.

From Contributor W:
It helps not to think if a platen as a polishing head. Think of it in terms of surface area. The harder drums have very little surface area touching the part so they have a deep, penetrating scratch pattern, very good for leveling. The softer the drum, the longer the contact patch, and the bigger the contact patch, the less depth of scratch because there are so many more grains in contact with the material. The platen is an extension of that idea. It has a massively wide surface area compared to the drums, so it has very little penetration into the wood surface. This means less scratch to sand out by hand if used properly. Platens are not required, but they are helpful if you are hand sanding all your products. A very soft drum can do a great job as well. Not as long a contact patch as the platen though.