Most sanding belts are now made with a diagonal splice joint that is held together with a strong piece of special tape. Then use CA adhesive to bind the bias binding tape to the cleaned edges of the sanding belt you want to make or repair. His solution is to store new and used belt sander belts in sealable freezer bags until he’s ready to use them.
“First, peel the remaining factory tape off the belt splice. Cut a piece of cloth bias tape about 2” longer than the width of the belt. Lay one end of the belt, grit-side down, on the bench; then apply cyanoacrylate glue to the end of the belt. Wrap the belt around and repeat the gluing process to reconnect the ends of the belt.
Test your joint before putting your newly glued sander belt on your sander. Unfortunately a lot of glues will not hold when used with a belt sander due to the extreme heat and tension your belt sander is under when working and it is best to buy a new belt that is designed for your machine, but if you need a quick repair to get your machine up and running again this is an option. You need something that has great strength and durability as your belt sander is a very hard working machine and your belt is going to be exposed to a lot of heat and tension.
First I should have said is that you want to clean the back of the belt with a wire wheel to expose raw abrasive belt backing , and maybe scrap the exposed tape with a knife to remove excess glue. Now when the belt bends round a roller , you may see a slight rise in the belt away from the tape at the joint like1/32 or 1/16 but I have not had a problem at the platten with failure or ripping of the belt. Just because it is holding the belt together does not mean it is ready for work !Note, that the steel bar clamping, forces the glue deeper into the Belt backing fibers.
how to repair belt sander Related Question:
Can belt sander belts be repaired?
You can also mend or make abrasive belts by this DIY method: Obtain some bias binding tape from a fabric store, or you can make your own. Then use CA adhesive to bind the bias binding tape to the cleaned edges of the sanding belt you want to make or repair. I have done this many times, and it works fine.
How do you glue sanding belts back together?
Lay one end of the belt, grit-side down, on the bench; then apply cyanoacrylate glue to the end of the belt. Lay half of the bias tape’s width on the glue, place waxed paper over the tape, and use a weight to press down on it for about 30 seconds, or until the glue sets.
Why does my belt sander keep breaking belts?
Heat, humidity, and age can contribute to belt seam failures, but they’re not the only causes. Check that your belts are turning in the direction indicated on the inside face. When not using your sander, release the tension on the belt.