Okay, so I over-reacted, I only watched a little of the video to get an idea of his "style." Pretty unfair of me eh?

If the belt just breaks it's a hassle but if 1/8" does it'll slap you a few times before you can get away or it wads up and parts completely. My memories may be from the old directional belt days when even mounted the right way they tended to wear a little faster at the joint.

My old 2" x 48" Delta used to break belts though not very often but usually painfully.

Agreed, you need to follow the prime rule of using a rotary tool, "Stay out of the Plane of rotation." 

Frosty The Lucky.

3 hours ago, Gazz said:

Without reading all of JHCC's posts, I don't recall if he made any comments about getting hurt by failed attempts to make his own belts.

Minor scratches, no more. However, when a 2x90 belt breaks -- especially a heavy one like a 36 grit Cubitron -- it's a dramatic experience, to be sure.

There are two things I don't like about the TOT video (apart from the jocular tone, which gets old fast): the first is using a file to remove the grit, which is a great way to ruin a file. The second is the method as a whole, which (as Frosty notes) creates unnecessary extra thickness at the joint.

I believe his lack of respect for tools and onscreen affectations turned me off right off.

Frosty The Lucky.

Had an 80 grit belt blow apart on me last night, which was a good reminder that I'd forgotten to rough up the cloth backing before gluing. Unfortunately, I've got a bunch of these that I made at the same time, so I think I'll just keep switching them out until the last of them lets go, at which point I'll reglue the salvageable ones.

The batch gluing of multiple belts has proven less of a timesaver than I originally expected. 

Maybe write down a successful procedure for gluing belts so you don't forget something doing multiples? If it doesn't save much time though . . . 

Frosty The Lucky.

My original intention for batch processing was to get a number of belts glued and clamped during the adhesive's open time, so that they could all cure together. The problem (apart from forgetting to roughen the backing) is that the Gorilla Glue doesn't have a lot of grab, so things have been slipping around and getting out of alignment. 

I'm playing with an idea for a clamping jig with a space for 2" x 3" (or thereabouts) plexiglass clamping block inserts, thus:

The idea here is to set up a belt with the ends in proper alignment, spread on the glue, apply the tape, add another plexiglass block on top, clamp everything together with a C-clamp or a couple of spring clamps, lift the whole thing out and set it aside to cure, put in another block, lather, rinse, repeat.

I take it there is no solvent component to the adhesive or the plexi will soften if not right away then in a couple few uses.

Frosty The Lucky.

No, polyurethane sets by chemical reaction with the moisture in the air or in the substrate. It sometimes helps to give the surface a quick wipe with a slightly damp sponge before you spread the glue.

Ah, now I remember. The tree strikes again. <sigh>

Frosty The Lucky.

Update: I think I need to re-glue the 36 grit belts. Every single one (so far) has refused to track and then blown apart, and I think juggling too many in gluing up a large batch made for both bad adhesion and bad alignment.

How many belts in that batch? Maybe a different clamp is in order?

Frosty The Lucky.

Update: upon closer examination, I discovered that the polyurethane had not adhered well to the backs of the 36 grit belts. Gluing up in batches had allowed the joints to go out of alignment. Not abrading the backing cloth and not clamping heavily enough had prevented the glue from adhering properly. 

I therefore reglued two of the 36 grit belts, first removing the glue residue and then roughing up the cloth backing with a farrier’s rasp. Both the backs of the belts and the splicing tape got a wipe with a wet paper towel. I glued up the belts one at a time, carefully aligning the two halves, clamping the joint solidly, and allowing each belt at least an hour under clamps to let the glue cure. 

No picture, but this appears to have done the trick. If nothing else, the reglued belts didn’t self-destruct within five seconds of turning on the motor. That’s an improvement. 

Yeah, not having the grinder belt disintegrate in my face is desirable, in fact I demand they don't.

Frosty The Lucky.

Here’s the back of a belt whose slice failed. As you can see, the glue did not penetrate the (unabraded) surface at all. 

Here’s a belt under clamps for regluing. Each end of the belt is held onto the jig by two spring clamps (four total), which allow very precise and secure alignment along the straight edge of the angle iron before gluing. 

The caul I used to hold down the splice tape this time is a 3” length of 1/4” x 1-1/2” flat bar, held down with a beefy C-clamp or (as here) a pair of smaller ones. 

The glue squeeze-out cleans up quite easily once everything cures. 

You used CAUL to clamp the belt down?  I'd ask how you applied it if I didn't have iced tea squirting out of my nose laughing!

Thank you John, wonderful typo, I'll be grinning every time I think about that one for a while. Just PLEASE no pics!

Frosty The Lucky.

Not a typo. In cabinetmaking, a caul is something you put between your clamps and your workpiece to distribute the pressure and ensure proper alignment. 

Some might argue that “clamping block” would be a more appropriate term in this case, but I’m not going to die on this particular hill. 

What did you think I meant?

I had to look it up and the definition (several hits worth) is the tissue composing the amnionic sack. There were a number of parts about caul births, where the caul covers the baby when it's born rather than discharge as the afterbirth. There were a number of other versions say covering the head or just blocking the nostrils, etc. Nothing particularly dangerous is someone clears it off.

I was getting a lot of really icky visuals regarding caul and belt gluing clamp. I'm glad my mental floss was good enough to eliminate them for a change. 

Heck, I've participated (so to speak) in livestock births including turning a breach goat kid and delivering it while Deb was phoning her goat vet friend in Mi. That was our first kidding season. I'd assisted dogs, cats, horses 3x and calves 3 or four times. Now I'm happy I you weren't using the stuff to clamp grinder belts. That creeps me out more than pulling a calf covered in blood and . . . stuff to my armpits.  

Glad you meant something else. 

Frosty The Lucky.

The first birth I participated in was when I delivered my daughter in the back of an NYC radio cab at the corner of West 104th Street and Riverside Drive in Manhattan. That was an experience. 

For everybody except the new one. I don't THINK we experience our own birth but I could be wrong. Was the cabby prepared?

Frosty The Lucky.

The poor man was terrified, but did his level best. He came to visit us some days later, and we got a photo of him holding the baby for her album. 

6 hours ago, Frosty said:

I don't THINK we experience our own birth but I could be wrong.

I think we can safely say that we experience it, but we don’t remember it. 

And I thought NYC cabbies had seen it all. It'd be a heck of a Kodak moment for anybody.

Well yeah, we experience it like a fender experiences a collision but I was wondering about the mental type experience. 

I've always thought Mothers should the ones celebrating the kid's birthdays but I don't think I know a Mother who agreed, my Mother just laughed but she was as odd as I am just smarter. 

MAN my thoughts are taking odd turns right now, maybe I should just close my comp. Blazing Saddles just finished and I'm still trying to catch up on the gags, puns and . . . uh Yeah, all that stuff.

Frosty The Lucky.

Update: The new method is an improvement, but not perfect. 

For starters, here’s a comparison between the previous batch and the latest. The belt on top is from one of the batch glued up as a batch and didn’t have the backing abraded. The one in the bottom was individually glued after the coating on the back was filed off. 

The joints were lasting longer before self-destructing. Indeed, one belt lasted long enough that I was close to trashing it anyway (remembering ThomasPowers’s dictum that you should “grind like the belts are free”). However I could see that the point of failure was still the interface between the glue and the belt. On the next belt, I abraded the joint area with a scrap of 36 grit bent, in the hope that the ends of fibers thus raised will increase the mechanical strength of the joint. 

In other news, I mounted a toggle clamp on the gluing jig, to simplify the clamping. Here it is, with some thin cardboard and some parchment paper between the belt and the caul. 

Here’s the most recent splice, out of the clamp but not yet trimmed or tested.

As you can see, the clamp was a lot tighter on the left-hand side than it was on the right. The bond looks decent, but irregular. I think I need to make the connection between the caul and its bolt flexible, so that it won’t press more on one side than on the other. 

An observation: One interesting characteristic of polyurethane adhesive is that a thinner layer is stronger than a thicker layer (not unlike hide glue, come to think of it).  Really hard clamping pressure across the entire width should help. 

That's pretty much true of all glues isn't it? Some cements work better with a thicker layer but it's a whole different thing.

Frosty The Lucky.