Adding friction material to timing belts
 

Is it possible to rivet or epoxy a grip surface like urethane onto the back of a timing belt? Is there a better way to attach friction material? We've tried polycord in the past, but found that it's painful to deal with the pulleys compared to just buying timing belt pulleys and belts. Plus, no need to tension.

Re: Adding friction material to timing belts
 

What's the application? Speeds? Is it a continuous belt?

I would suggest looking into brushable urethane. 1114 used it on their rollers in 2014. While not the same application, it shows that it is relatively durable and has grip. Rivets might work but you would have to turn a channel in the center of the pulley so it doesn't cause any interference. Standard epoxy would be to brittle and I don't have enough experience with flexible adhesives to touch on that.

Re: Adding friction material to timing belts
 

I'm guessing that you're using this for a lift/feeder or similar traction mechanism.

Something to consider in addition to the connection: the grip material must either be in discrete pieces, or must stretch enough to allow the belt to pass around the smallest pulley you're going to use despite the lamination. I've never done this, but it seems that a relatively thin layer of rubber cement or silicone adhesive applied to the outside of the belt would serve both as the adhesive and (once it cured) the grip surface, and would have the necessary give. Durability of these may be an issue. I'd recommend getting several short belts and trying a number of different adhesives in a small test rig to see if you can find any that hold, wear well, and don't chemically damage the timing belt.

Re: Adding friction material to timing belts
 

Shoe Goo

Re: Adding friction material to timing belts
 

The vertical conveyor on 469s 2012 robot was a single strand of timing belt without any sort of friction material added to it. Worked perfectly.

Re: Adding friction material to timing belts
 

So it looks like brush-on products are the way to go here. We'll have to do testing on how well it adheres.
It is for an intake mechanism, maybe for next year. Thanks!

Re: Adding friction material to timing belts
 

You could always try a flexible latex caulk as a grippy material, or as something to attach a stretchy grippy material. I work at a lumberyard, and Lexel always advertises that their latex caulk is super flexible and adheres to everything, and from the display samples I've seen, I have no reason to dispute that. It might work, it might not, but there is only one way to find out.

Re: Adding friction material to timing belts
 

I doubt a latex caulk would be tough enough.

Shoe goo adheres tenaciously and is tough and flexible.

I repaired a split tractor seat cushion with it. Four years of abuse and still no sign of letting go.

Re: Adding friction material to timing belts
 

Years ago there was a track style robot in the PNW that used timing belts as the tracks. They were custom made timing belts that had a urethane backing on it. They were extremely grippy. They were like a 2" wide belt and if I remember right they weren't all that expensive considering their size and that they were custom built. I'd check with Gates and see if you can get a pre-done solution.

Re: Adding friction material to timing belts
 

Just so nobody gets the wrong idea about the paint on urathane I wouldn't mind commenting on this. Yes we did use this for our intake rollers in 2014 (also 2012 and 2011), and it served us well. Although we replaced the rollers more then you might think. I believe we changed them every day almost, so it might not be as reliable or durable as you think.

Re: Adding friction material to timing belts
 

Was it the urethane material itself or the bond between the urethane and PVC that was failing? And if it's the latter, could you detail how you prepped the roller surface before applying the urethane?

Re: Adding friction material to timing belts
 

I believe it was the bonding into the PVC rollers that would start to peel off once it got a cut out hike in it. I want apart of the people who made them all the time, but I believe they cleaned each one with rubbing alcohol before applying.