Splicing grinder belts

[JHCC]

So, here’s the first experiment with Gorilla Glue, as clamped and cured to splice a heavy 36 grit ceramic belt:

 And after a bit of use:

It seems to be holding up fairly well so far, although I’m reserving judgment until I’ve had a chance to try it on a belt that I’d not previously glued up with something else. 

One thing is for sure: it didn’t self-destruct within 30 seconds, like some of the other splicing materials I’ve tried. 

[Gazz]

The glue in the drive belt kit came in unlabeled small jars and I suspect the belt seller is repacking the stuff for use with his belts.  I got the kit from Al Bino Industrial Belting (no joke!) so maybe you can find him and discuss the possibility of just buying the cement from him.  I have interest in your efforts as there is a local guy selling 24 grit belts for short money that would require splitting/resizing before I could use them.

When I tried to make the drive belt from an automotive serpentine belt I used two plates of aluminum as platens with the ends of the belt clamped between them and then heated gently with a torch.  At the time I did not have a non-contacting thermometer so I just watched for the melted rubber to ooze out.

[Frosty]

I'd give a coarse grinding wheel a try though any grit should work.

Frosty The Lucky.

[JHCC]

Update: did some fairly heavy grinding on the 36 grit belt. The splice is holding for now, although it’s started to delaminate a little. I strongly suspect that this is on account of having previously been glued with cyanoacrylate. The tape itself is slightly abraded on the back, but is otherwise fine. 

The thinness of the tape is a real plus, and I’m not feeling any “bump” as the splice goes past the workpiece. And, as noted, no sudden explosions. 

[Frosty]

I'm following closely in case I have to splice belts. I have a 2" x 72" and rolls are sooooo much less expensive than made up belts.

IF I can splice them and have them live longer than wear time.

Frosty The Lucky.

[jlpservicesinc]

Following along too..   I make all my own bandsaw blades for the same reason.. 

[JHCC]

An additional thought: the 36 grit ceramic belt is pretty heavy and stiff. The delamination shown above is probably aggravated by going around the 2” diameter wheels of the grinder, and I suspect it will be less of an issue with thinner, more flexible belts, even if the adhesion doesn’t improve. 

[JHCC]

Important update: The belt failed yesterday, but the circumstances are interesting and worthy of a little forensic examination. 

I was grinding the inside of an anvil bridge I’d wired up from some heavy C-channel, and at first, all was going well. Then, to better reach a particular spot, I switched from what might be called “edge down” (A) to what might be called “edge up” (B):

At this point, one of the corners that had previously delaminated caught the workpiece, and the belt ripped itself apart:

If you look closely, you can see where the corner took the fatal impact:

 Analysis: failure can probably be traced to lack of adhesion between the belt and the tape. As noted previously, this belt had previously been glued with cyanoacrylate and fabric, and even after removal of the old splice and abrasion of the surface, adhesion wasn’t uniform. That led first to the corners sticking up and then to the joint failing under the stress of one of those corners hitting the workpiece. 

(Note that while the tape did rip, the longitudinal fibers maintained their integrity. That’s a good sign.)

Next steps: I think I’m going to try regluing this joint, just to see how it does. The next belt I glue up will be from new, unglued stock, so as to get a better idea of how the tape adheres to the banking under normal circumstances. I think I may try breaking the glue layer of the belt itself, to give the joint more flexibility going around the grinder wheels. 

[Frosty]

I have a couple thoughts. I don't recall if you're making butt or lap joints. 

If lap joints I think there might be a slight bump, too slight to feel, that is initiating a tear. 

Butt joints look like an adhesive failure. Being thicker less flexible belts sure could be an exacerbating factor. If not the problem.

I wish I could be some real help.

Frosty The Lucky. 

[JHCC]

This is a butt joint, and it was holding up really well until I caught that corner. I agree that there's an adhesive failure; my only question is whether or not that will be an issue when gluing clean material.

[Frosty]

Hmmmm. Maybe inspect the joint before turning it on and occasionally in use?

I'm sure you'll get better adhesion to clean belt. How are you cleaning this belt?

Frosty The Lucky.

[JHCC]

On 12/31/2023 at 10:37 AM, Gazz said:

The glue in the drive belt kit came in unlabeled small jars and I suspect the belt seller is repacking the stuff for use with his belts.  I got the kit from Al Bino Industrial Belting (no joke!) so maybe you can find him and discuss the possibility of just buying the cement from him. 

From what I can see on the Al Bino website and some discussions on the Practical Machinist forum, this is a two-part adhesive for their synthetic drive belts. Apparently, these belts have a nylon core that requires a special adhesive.

2 minutes ago, Frosty said:

How are you cleaning this belt?

This specific belt had previously been glued with cyanoacrylate, so I scuffed up the surface with some rough sandpaper to try to get all the old glue off. I suspect that it may have penetrated the fibers of the cloth belting, preventing the polyurethane from getting as good a grip.

[Frosty]

Cyanoacrylates are generally susceptible to acetone or MEK, (Methyl Ethyl Ketone) solvents which might be a good way to remove old maybe degraded adhesive. 

I'm sure cyanoacrylate has penetrated the fabric, that is one of it's best features or it wouldn't be very good for tight joints.

Frosty The Lucky.

[Goods]

Any thoughts on changing the angle of the splice for the thicker belts? The angle look a little shallow to me, but I’m not at the shop right now to compare.

Keep it fun,

David

[Frosty]

I was thinking about splicing on the bias too David, say 45* to pick a number. Unfortunately my voices are telling me that no matter which direction the belt is going the leading edge of the splice will be a little point for minimum adhesive bond and maximum snag. 

I'd partly written a reply (in my head) with a frowny face emoji when it occurred to me that a crescent shaped splice might do it. The tails of the crescent trailing in the belt direction of travel.

That would spread the impact point of the splice across a wide area, less so that a square splice granted BUT the corners are trailing and might fray but couldn't catch and peal the joint.

Hmmmm?

Frosty The Lucky.

[JHCC]

Interesting idea. I suppose one could make a curved punch for cutting the ends of the belt.

[JHCC]

As noted elsewhere, I jury-rigged quite a good setup for splitting belts:

I’ve got some ideas for making this a permanent setup. More to come.

In the meantime, I’m gluing up the two halves, using the same cut angle as the original. The splice material is the blue tape, glued down with polyurethane adhesive. I’ll keep y’all posted. 

[Gazz]

Saw this today.  Interesting way to remove the grit at the overlap.

 

 

[Frosty]

It looks like a decent method. I was less than impressed when he kinked the belt so it'd lay flat though. I YELL at people who kink my belt grinder or sanding belts.

Frosty The Lucky.

[JHCC]

I actually tried something very much like that, utterly without success. I suppose a lot depends on the belt itself; I had no luck with the heavy grit and tough adhesive of a 36 grit cubitron belt.

 However, I can report that the blue tape is working pretty well. I did have one belt let go in use, but that was one that had previously been reglued, and I don’t think the adhesive bonded properly to the fabric. 

[JHCC]

On 1/26/2024 at 9:09 PM, JHCC said:

The splice material is the blue tape, glued down with polyurethane adhesive. I’ll keep y’all posted. 

Quick update: the belt dulled before the splice blew out. Better than the other way around.

[Gazz]

I recently bought some belts from AA abrasives and through the miracle how your internet usage is monitored/tracked, I now see ads from AA Abrasives when I poke around on youtube.  In one of their ads, they show making belts and are using some kind of thermoset glue to join them.  While the Yankee in me finds this kind of thing (making your own belts) intriguing, I've decided I'm just going to buy the belts I need ready made as time is becoming more precious the older I get.  I'll still make my own bandsaw blades though as that is less of a mystery.

[JHCC]

I often see ads for Combat Abrasives, which reminds me of how ridiculous it is that so many things are (mis)marketed as “tactical” these days.  Then I remember that you can change the “C” to a “W”, and I feel better. 

[Frosty]

I'm with you John, "tactical" has just become a marketing buzz word and so meaningless. However your suggestion that "combat" be changed to "wombat" (and by inference be just as meaningful) reminds me of a favorite author of mine. Larry Correia and his "Tom Stranger, Interdimensional Insurance Agent." Tom Stranger carries a "CCW (CorreiaTech Combat Wombat) pistol." The thing does almost anything of a destructive to targets nature.

Excellent books when you the need for some escapist reading. I see by this search there're a couple new titles out. 

Combat Wombat is also an Australian computer animated cartoon.

I guess it's just too good a phrase not to use.

Frosty The Lucky.