Sanding Belts for power sanders

[LCHIEN]

Well, I broke 4 belts today.
One broke while I was using it and I went to my box of belts I bought some years ago and put a new one on, broke after a few minutes of use, repeat twice more and I have come to the conclusion that the adhesive on the joint tape is too old and comes apart under stress,

Its just a 1x30 inch sanding belt.
I don't usually change them too often and maybe I should because I before today I had about 12 belts and now they are all worthless.

I have some 4 x 36" bets with the same problem.

How often do you change belts? I dress mine with a belt cleaner periodically and they don't really seem worn out.

Looking at Amazon and the local hardware box stores, they all seem to sell 10 or more belts at a time in assorted grits.

Am I not changing mine often enough that 9 of them go bad at the same time?
Am I not changing grits often enough? I tend to leave about 100 grit on at all times. 80 on the bigger 4x36 belt sander.

Is there any way to salvage them?

I cut up the 4x6 belts and staple them to the sides of a piece of 2x4 to make disposable hand sanding blocks.

[Condoman44]

I have had this problem also. I don't think the glue at the seam ages well.

[Pappy]

If there is a way to salvage one I would like to hear it. I haven't found anything that works.

[Carlos]

Another weird one, I've never had one break, and I buy cheap ones, then store them in a garage that sees 110 degrees in summer and 40 degrees in winter. I have small belts that are a decade old because there's was a huge sale and I stocked up. My big edge sander belts are 1-5 years old.

Maybe you guys are being too kind to your belts and need to expose them to the harsh realities of Arizona life, so they straighten up!

[capncarl]

I wrote about this last year,
#1 Sander belt splice breaking

05-26-2019, 03:10 PM
I learned something today. I’ve been having a rash of sanding belts breaking on my 6 x 48 Delta sander and 4 x 36 sander. Some of the belts lasted only a few minutes before they broke. Previously a belt would last until there was no grit left on the belt. I buy belts from several vendors at a local car show and parts swap meet, usually Klingspor or other German mfg”s because of the good price. A tear down and parts inspection of the sanders didn’t reveal any unusual wear or any reason for the belts to break prematurely. After breaking 12 belts I decided to Google it and see if anyone else has this problem. I learned that these belts with a tape splice only have a one year shelf life. Now I know, don’t buy a trunk load of belts from a source that you don’t know how old they are.

Part of what I found out was the splice glue is shipped from the mfg. to the belt spacing companies frozen in dry ice.

The HF 6”x48” belts seems to last a long time and the 5 Belts for $15 is comparable to what I buy at Auto Show vendors. I think they also sell 1x30.
capncarl

[LCHIEN]

I am now sure that being stored in the garage at 90+ temperatures in the Houston summers is not good for the adhesive. I just tossed half a dozen 1x30 belts into the trash. I had to buy package of 10 so I guess I'll be much more generous about changing them out now. No use using one for five years.

I will keep a few of the broken splice belts to use to wrap around dowels to make custom hole sanding tools.

I'm going to keep my spare belts in the house under A/C from now on.Sounds like that will make them last longer, maybe.

[LCHIEN]

I wrote about this last year,
#1 Sander belt splice breaking

05-26-2019, 03:10 PM
l

https://www.sawdustzone.org/forum/discussions/tool-talk/836725-sander-belt-splice-breaking

[d_meister]

I was thinking that there has to be a way to fix them, and that if so, there's a YouTube solution. Yup:

https://www.youtube.com/results?search_query=glue+sander+belt

[capncarl]

Good luck with keeping the belts in AC and splicing! I suspect that by the time you purchase bias splicing tape you could easily purchase enough new belts you won’t have to repair splices. The older belts that used a laminated piece on the back of the belt for the splice......bless their heart.... made your sander knock with every revolution of the belt when it hit the back up plate. Terribly annoying and nearly impossible to sand a flat surface.
My understand of their splicing says the expected life of the splice is one year. My experience says they are right, when the splice fails, every belt in that batch will soon fail!

[LCHIEN]

Well it was cheap and simple to make a jig for that one Youtuber guy who used for 500 grit paper as the patch and PVA glue (basic carpenters glue) So I glued one up tonite and I'll see if it holds tomorrow. THis is more work and I've already ordered and received some new stuff, but I just had to see if it worked.
I'm a little skeptical that the sandpaper will hold.. Maybe some Tyvek based plastic paper but I don't seem to have any. Those envelopes you used to get that you could not tear, those were Tyvek.(PuPont Polyethelyne.fiber based paper)

The fabric patch I'm sure would be too thick. But hey the sandpaper is paper and the backing is paper so wood glue should hold them well.In tensile paper is pretty strong.

Hey! I just remembered the USPS express mail envelopes they will give you for free at the post office are all made of Tyvek. I have some. Will try tomorrow. not sure if PVA sticks to Tyvek which is really Polyethelene. THistothat.com was no help.
Dupont has this page https://www.dupont.com/packaging-mat...e%20adhesives.

Update: OK the glue held the sandpaper patch real well but the joint failed with the patch ripping at the seam after about a minute of operation and a lot of flexing.

[capncarl]

The splice the mfg. uses looks to me like thin reinforced filament shipping tape. I couldn’t get that to hold, but I didn’t use any extra glue. The belt is under quite a bit of tension on the machine, and every time it goes past the back up plate it tends to get scraped a bit. You have to admit that the splicing material that the belt maker uses is quite strong! The 3x24 belt splice is only about 1/2” wide.

[LCHIEN]

The splice the mfg. uses looks to me like thin reinforced filament shipping tape. I couldn’t get that to hold, but I didn’t use any extra glue. The belt is under quite a bit of tension on the machine, and every time it goes past the back up plate it tends to get scraped a bit. You have to admit that the splicing material that the belt maker uses is quite strong! The 3x24 belt splice is only about 1/2” wide.

Clearly they use something like a filament tape, but I am sure they use something other than the pressure adhesive you find on preapplied packing tape rolls - for one thing it never really "cures or sets".
The adhesive is under very strong shear forces.in line with the joint.

[capncarl]

https://www.google.com/search?q=metabo%20623530000%20adhesive%20sanding%20belt%20bonding%20tape

This appears to be the proper material for splicing your own sanding belts.

[LCHIEN]

One and only one Amazon Q&A Review on this tape:
I have some older sanding belts that have lost their adhesive and come apart on the belt sander. I tried this tape, but it is not holding. any ideas?
Answer:Tape is junk. Overpriced packing tape. I don’t know why they allow them to sell it on here. Nobody has any instructions on how to use it either.
By Brian R. on May 8, 2020

[LCHIEN]

My final report - I tried the Tyvek First test I just made a one inch wide loop of the material overlap 1" bonded to itself with PVA glue and it stuck like no tomorrow. I pulled on the loop and could not break it. Very promising, I was worried PVA glue would not bind well to Polyethylene Tyvek.

Next test I repaired a sanding belt sandpapering the ends first and using PVA overlapped with two inches wide Tyvek patch.
Result: Failure. The Tyvek quickly delaminated under dynamic load leaving a thin layer firmly bonded to one end of the belt and then the thinned remnants ripped quickly at the seam.

CapnCarl, thanks for the research on that Metabo tape but the one review on Amazon says it doesn't work for that purpose and its is surely not listed as sandpaper belt bonding tape in the Amazon description of the same Metabo number.

So my curiosity test is over, Fortunately I have new belts and I will try and store them better and change them more often (might as well not economize and try to squeeze a long life when you have ten (minimum purchase) and the life is only 1 year.

[d_meister]

Had a look at the Metabo tape, but could find NO info on proper application. Does one just stick it on and hope for the best? How about applying it linearly in multiple rows on the inside surface? Maybe there's a catalyst/accelerator that isn't available in the U.S. It's hard to imagine that various outlets sell this material for $30+ and it's completely useless.

While looking at the Metabo google results, I found this:.

https://www.sheldahl.com/technology/splicing-tapes/pre-coated-abrasive-belt-splicing-tapes

They specify "thermosetting" in their ad copy. Perhaps the lone Metabo reviewer missed the instructions (in German?) about using the iron to melt the adhesive into the fabric. Speaking of destroying SWIMBO's iron, I seem to recall reading about using heat to release PVA glued parts, so maybe using heat to achieve improved penetration could help?
Fun topic, too bad I don't have sanding belts to go all mad scientist on.