When using my 4×24 belt sander I keep getting rough spots on my slabs. They’re about an inch wide and a few inches long and rougher and deeper at the end. Looks like I stopped moving my sander and dug into the plank. I’ve tried several fixes such as running the sander completely to the ends of the board with each pass and making sure that the ends of the sander go out over the board ends. Still no cure. I wonder if I need to alter the platen or something. Any ideas?
Thanks,
G. Rose
Replies
Inspecting the platen should be step one - if should be clean and flat (I once had gummed up gunk on it after the belt overheated...). Also, with a belt sander it is very easy to apply uneven pressure which can make for a bumpy ride and a bumpy result, especially when starting and ending a pass (don't ask me how I know).
G,
What kind of wood slabs are you using and how big are they ?
Sometimes the belts can get clogged up or filled up in areas and cause an uneven surface so take a look .
I have belt sanded many a Redwood burl slab and such and found sanding across the grain an effective method to rough it smooth then finish with the grain .
good luck dusty
Thanks for the response. I use several kinds of hardwoods and softwoods (walnut, mahogany, cherry, oak, pine, etc., etc.) I get the same result on all. This has not always been a problem, so maybe I need to do something to my sander. I also sand glued-up slabs cross grain first if my glue joints are less than perfect. But then when I san with the grain, the same problem occurs. I'm sort of of the opinion that I need to change the steel platen to graphite or something?????
See if you can get a sanding frame for your sander, that will eliminate the gouging. Or better yet get a good old #7 plane and have plenty of nice shavings instead of all that dust and a good workout to boot.
O.K., thanks.
It's something systematically wrong, either in the sander or your technique.
1) Make sure the platten is clean and free of gunk.
2) More probable, it's something in the way you're working. Using a belt sander you should never, not for one second, stand still in one spot. When approaching the ends of a board you need to be extra careful not to change anything in your motion; continue out past the end as if the board had another 6" of length. Don't press hard - let the sander's weight do most of the work. And finally, try sanding at diagonals (instead of with the grain), alternating left and right. You're gonna take out the scratches with a ROS afterwards anyway.
David Ring
http://www.touchwood.co.il/?id=1&lang=e
Thanks for your help. I do go out over the end of the board and I THINK I avoid stopping at all during each pass. I'll try what you suggest and see what happens. Thanks again.
FWW had a good piece about checking and changing a platen in one of their belt sander tests iirc .......... should be on the site somewhere. In addtion to the previous advice I would suggest using a belt cleaner ....... it's just a big gummy rubber stick. like this http://www.toolmarts.com/pc_48115.html Clumps of buildup can affect your finish.
O.K. Thanks a lot.
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