Breaking Sanding belts

[LCHIEN]

I think your reasoning about the glue is probably true, but I do wonder if there is any shrinkage that happens with that kind of material.

I'm just spitballing, I don't have much experience with belts. Even on my OSS I rarely use it.

I think the shrinkage is minimal. The Belt sander has a spring loaded tensioner that depends upon a spring, springs with age get weaker if anything but not tighter. BUt anyway the spring looks to have a travel of about 1/4- 1/2" to take up the slack.

[rcplaneguy]

My dad stockpiled (new at the time) sanding belts in the 1990s. I inherited them and recently tried using. Every one failed almost instantly at the diagonal joint. I tried regluing a few but was unsuccessful. After breaking 20 of them I went to Lowes and bought a new one. The new one has worked perfectly for many uses. The lesson? Toss the old belts.

[leehljp]

Not an expert on this but from experience with observation and not so scientific logical deduction: Numerous seasonal humidity changes breaks down the glue. I have some 6 in belts that still work fine after 20+ years, but they stay in a thick cardboard box. And I have had some 3 inch that came undone after setting up for about 6 or 7 years and then putting on my makita sander. My 3 inch belts were not boxed like the 6 inch belts.

These are belts that started out here in the states, went to Japan and came back with me 3 years ago. I took the 6 inch over in 1989, and the 3 inch belts around 2001.

(HF belts on the other hand did this when new.)

[Cochese]

I think your reasoning about the glue is probably true, but I do wonder if there is any shrinkage that happens with that kind of material.

I'm just spitballing, I don't have much experience with belts. Even on my OSS I rarely use it.

[LCHIEN]

don't have any reason the tension would have changed in all the years I've had the sander. Seems to be reasonable when I close the tensioning lever.

[Cochese]

There's not too much tension on it?

[LCHIEN]

I have a Ryobi 4" belt 6" disk sander.
Fired it up today when it was 43 degrees in the shop and the belt broke.
replaced it from a box of belts I ordered way back and it broke when started. Replaced another and it broke immediately on startup.

So the belts 4" x 36" are Nortons. The copyright date on the cardboard sleeves says 1997 but I didn't start woodworking until 2000 so I doubt they'd be before about 2003 as the copyright date is not indicative of date of manufacture, just the package design.

So the belts are all breaking at the diagonal joint, there is a strip of tape that pulls off of one end, after a couple of rotations. I'm presuming that 10 years old, the adhesive is dried up? I don't think the cold has anything to do with it?

I have more but I figure after 3 there's no point in trying.

Is there any hope of repairing these with new tape? What kind of tape? Looks like a fiber tape, the adhesive would have to have a pretty good shear strength due to the tension on the belt.

These belts are butted and taped, not overlapped and glued.