Promising solution for old sanding belts that break at seam!

[Matt Uchida]

One day after having not sanded with my delta 1x42" belt sander for a long time I noticed that all of my sanding belts were breaking at the seams. After reading all over the internet and here I discovered that the adhesive used apparently doesn't last forever and they use some sort of special industrial process. So I figured I was out of luck and would have to throw away a dozen unused belts.

Well I think I found a solution!

In my first attempt I used the same tape that was on the belts and reaffixed it to the belt with contact cement. Did the basic instructions on contact cement and reattached the tape to the belts. I think I used a solvent to clean it first. I haven't tested it extensively but I did put it on the machine and used it to sand with no problems. Probably ran it for a good half hour.

Since it is hard to get that adhesive tape off in one clean piece I went searching for other possible products. I was going to try muslin because it is very strong and should hold onto the contact cement well but instead my mom suggested some sort of poly ribbon. Not the type you wrap presents with but some sort of woven one that you would trim certain sewed materials with. She had 1" wide type and when I gave a good tug on it the stuff was stronger than I could imagine. I was unable to break it pulling with both hands. So I went to work and did about 6 belts. I cut a strip of the material, did the contact cement thing, then clamped it together for a little while. I haven't tried these belts yet so I will have to report back on these results. My one fear is that any of the alternative materials might fail from rubbing. They are all very flexible so that should not be a problem.

I also have no idea how well this will work on a belt that is very wide like 4-8" but I think it may work as long as the material is applied evenly.

Hopefully there is new life in our belts yet!

[Jim Andrew]

Good topic. Will be glad to see your results.

[pat warner]

Would not risk a hand made splice.
Break a belt unexpectedly and stuff could go flying in your face.
But, alas, :
Long length unspoiled belts, when glued to granite or glass are great for sanding and sharpening. You won't find sheet stock that will span your granite plates.

[Matt Uchida]

Would not risk a hand made splice.
Break a belt unexpectedly and stuff could go flying in your face.
But, alas, :
Long length unspoiled belts, when glued to granite or glass are great for sanding and sharpening. You won't find sheet stock that will span your granite plates.

I am a little worried about that but I noticed a pattern as these 12 belts broke. Each one that broke pretty much stopped instantly. It made a loud scary noise as the tensioner snapped open but nothing went flying. If I had my hand real close it might have scratched it a little but I didn't feel in any danger since the belt stopped moving instantly. I don't know what would happen in the case of a 4" belt or 8" belt but I would expect something similar.

[John McClanahan]

I'm all for trying to save the belts. Having the seam break is no more dangerous than having a band saw blade break. The only problem I see is finding a strong glue that doesn't get too stiff and brittle when it dries.


John

[Chuck Saunders]

i don't think a broken belt offers any threat at all. It doesn't have the rigidity or confinement that make a bandsaw blade risky. If the glue holds great, if not, it was worth a shot.
Chuck

[Kevin Bourque]

I have a 6' stroke sander and I have to glue up all my belts from roll stock. The previous owner gave me a homemade splicing jig to cut the belts. Its sort of employs a cookie cutter method. Then I use contact cement and whatever thin cloth material I have lying around to secure the splice. Works like a charm.

[Jim Laumann]

Matt

THanks for posting - your idea ounds promising....broke two myself this week.

Looking forward to your results.

Jim

[pat warner]

"i don't think a broken belt offers any threat at all."
*****************************************
Whilst we might like to look adversity in the face, it may not be the best policy when it come to safety. A sander, innocuous as it is, can still take its toll. Should you break a belt (stationary edge or edge/radius sander for example) there could be surprises. E.g.:
1) You're startled. Whether in a car, on a bike, battlefied, coldcocked in the bedroom, or poised at your sander, being startled can present adversity. If unprepared, lulled or whatever, the crack of a broken belt or bandsaw blade is an unwanted surprise.
2) The belt break (a wave of fabric or paper) may slap you, pull the work out of your hands or sling it across the room. & the edge of a broken adhesive belt is sharp and can cut metal & protoplasm.
3) If you have table fixturing or a 90° fence e.g. the belt will most likely bunch up in the gap and may take you or the work along with it. Moreover, it will spoil your setup.
4) Sanding belt abrasions are painfull, long lasting, slow to heal; I know.

[Matt Uchida]

"i don't think a broken belt offers any threat at all."
*****************************************
Whilst we might like to look adversity in the face, it may not be the best policy when it come to safety. A sander, innocuous as it is, can still take its toll. Should you break a belt (stationary edge or edge/radius sander for example) there could be surprises. E.g.:
1) You're startled. Whether in a car, on a bike, battlefied, coldcocked in the bedroom, or poised at your sander, being startled can present adversity. If unprepared, lulled or whatever, the crack of a broken belt or bandsaw blade is an unwanted surprise.
2) The belt break (a wave of fabric or paper) may slap you, pull the work out of your hands or sling it across the room. & the edge of a broken adhesive belt is sharp and can cut metal & protoplasm.
3) If you have table fixturing or a 90° fence e.g. the belt will most likely bunch up in the gap and may take you or the work along with it. Moreover, it will spoil your setup.
4) Sanding belt abrasions are painfull, long lasting, slow to heal; I know.


Just want to explain my reasons for why I think they don't pose serious danger.

#1. I broke around 12 belts and never did it do anything more than startle me. The belts always stopped immediately, never grabbed my work, and never touched me. Just to be clear I sometimes sand small pieces and my fingers are a matter of a few millimeters from the belt.
#2. The belts have no significant mass to keep them turning as would a blade or grinding wheel. Likewise nothing would have much force to torque a piece out of your hand. Also I have many a piece flew while sanding so I know to always keep a good grip.
#3. The belt is able to turn because it is held tight by the spring tensioning device (I don't know the name of it). As soon as the belt snaps it has no more tension to keep it against the wheel in order to keep it moving.

But to be clear I am not saying that nothing could ever happen. I am not familiar with every type of belt sander there is so it is up to the individual to consider other possible dangers. I specifically used a 3 wheel 1x48" sander.
Maybe one could make sure to use the belts for something in which their hands don't get close?

[Keith Outten]

There is a YouTube video that demonstrates a technique for repairing belts for 1x48 belts. The guy uses USPS strapping tape 1.88" x 360".

I think that the smaller belts are pretty safe to repair, larger belts on edge sanders and other types of machines might be higher risk.
.

[Matt Uchida]

UPDATE:

My proposed fixes have not worked quite as well as I had hoped. Out of the 3 that I have tested all experienced failure. The ribbon didn't break but the glue started to let go. The one with a longer piece of ribbon seemed to survive longer probably because of increased glue surface. All 3 failed belts worked fine for approximately 30 minutes of grinding before failing. To clarify I was grinding mostly stainless steel for my knife and other metal projects. This created a lot of heat obviously and that heat may have played a significant role in the failure, I am not sure. Perhaps heavier grinding also caused the ribbon material to sort of pull away. A thinner material such as that used by the manufacturers might do better. Doing woodworking might also fair better than metal grinding, but this is just speculation.

So perhaps the next step in testing is to see if there are any glues that are as flexible as contact cement but better performing. I might also see if I can tell whether heat weakened the bond significantly, that should be a relatively easy thing to test out. Perhaps hang a sample with a weight then apply heat to the belt?

Maybe as Keith mentioned USPS tape would work. I am assuming that it is the type with the fibers that run lengthwise? This would be much thinner and still strong.

[Lee Schierer]

Heat is certainly the enemy here. The adhesive on nylon reinforced tape will fail rather quickly when heated.

I've had numerous belts break on my Porter Cable 3 x 20 sander without any problems. The belt simply stops as soon as the break occurs.

[Phil Thien]

You're startled. Whether in a car, on a bike, battlefied, coldcocked in the bedroom, or poised at your sander, being startled can present adversity. If unprepared, lulled or whatever, the crack of a broken belt or bandsaw blade is an unwanted surprise.

I'd take a broken belt over being coldcocked in the bedroom any day of the week.