Just like the subject says, what cord are you using and why do you like it?

I am a supplier so my response is based on my testing of what is available. Basically what we are seeing is high strength material. polyethylene, woven into a filament.

It is a patented product and is branded as Spectra® in the USA and Dyneema® offs****. Been around for some time and used in ropes (lines) for sailboats for it's low stretch and high strength abilities.

It is also used for flying kites, spear guns, fishing, etc. It is what is used for kite boarding and parasailing.

It comes dyed / coated with colors or natural and in various weave strand count, breaking strengths / diameters. Higher weave count is best obviously depending on if you are using it to cut urethane or to keep you flying a parasail.

Obviously it doesn't cut adhesive but pulls against it to the point of failure, tearing the adhesive. This is why you see some debris associated with using it whereas with wire you don't.

There is no difference on what is avaliable other than what is mentioned above.

Size matters as the thicker it is the harder it is to pull through urethane. Just like anything.

Abrasion is the enemy and if you can keep it from snagging on burrs from pinch welds, it is reusable. Just like fishing string, if it is damaged the strength is reduced.

Hope that helps.

Rick

Thanks for explaning the composition of the cord. I now know a bit more about it and ordered some of your X Filament to try out. I have used the Zipline & Ripcord HD previously as well as the squire wire and this is with a Viper Tool.

Since I live in Colorado, the cars I see are always dirty as hell which contaminates the cord and sometimes it's colder than anybody in their right mind would be wanting to work in. I feel that environment plays a major difference when using cord to cut out windshields. Basically, it takes more force to cut (or stress) cold dirty butter than warm clean butter. With that said, I'm looking for the strongest cord available. My post is mostly intended to locate that so that I save money in the long run.

Unfortunately the higher breaking strength is also the larger diameter and therefore the most difficult to move through the adhesive. Sometimes it is better to use wire on some removals. Thanks for the order. I will include some samples of our other two sizes for you to try as well.
Rick

I've been testing...
Actual wire is a last last resort.
Zipline works pretty good.
Gorilla cord is too much for the bot. The drag bogs down the motor.
Ripcord HD is wonderful but its too expensive.
WRD P8 is the one I have not tested yet but I will be testing that soon. I hear great things about it.

If the Gorilla drags down the Bot I can only imagine how hard it is to crank. I've never tested anything near that thick.

One concern with cord is the capacity of the winder to stay anc****d when pulling really hard. Rotational forces have an influence as well.

The thinner it is, the easier it is.

Rick,

"I have never tested anything that thick" That's what she said!

Junior, you've been reading those bathroom walls again?

I'll also mention that using larger diameter material can cause some lateral forces within the winding drum as it is compressed under loads. Thinner is better.

Has anyone tried the braided fishing line? It seems that the comparible tensile strength is equivalent in mm diameter to the windhield specific cord. You can get much higher tensile strength than what is offered for windshields. It is way cheaper and there is way more selection.

Yeah, with the thick stuff it fills up quick and is the cause of the motor loosing power. Too bad, that stuff is so strong. I used it on a 1708 and the bot was not happy. Since I have you here... Any chance you are working on an update to the inside angle/anchor cup? The small one is great on anything flat. The two roller can't be trusted and is too bulky. My thoughts...Same design(as the small one) for the angle wheel, longer shaft with at least a 4 inch side pump cup that will stick to curved parts of the glass. A better inside angle cup and your kit its untouchable.

Mike, I have synthetic in 200, 250 and 300 lbs breaking strength. If you are breaking this material something else is going on. I can't get an answer from the other suppliers on their breaking strengths.

I'm always working on new stuff. The most common situation that puts the APEX at a disadvantage is the angle of the cutting element between the Bot, the APEX and where the cutting element exits the adhesive. Having extreme angles will multiply the pulling forces to work against the APEX. Relocating the Bot to lessen the angle will reduce the force on the APEX. Think of it like pulling back on a bow string, the further you pull it back the more force is applied.

The reason for the size of the APEX is to distribute the loads over a wider area. Smaller device would counter this purpose, putting more force on a smaller footprint.

Longer shafts on a smaller cup would again, multiply the forces and add a lever arm / fulcrum force to twist it off the glass. Keeping the pulleys close to the cup reduces these forces. There is a thresehold of where you get diminishing returns in the design.

Unfortunately the area you need this to work is normally where the most curvature is located and the need to have a curved glass cup means you have a reduces ability in your holding power. Curved glass suction pads have larger flexible lips specifically for curved glass and don't offer as much holding power as a flat glass pad.

I have a bunch of failed concepts for this situation from a long arm with anchor prongs to sink into the adhesive and others. Obviously this didn't work because of concern of it letting loose under pressure and the differing distances of the urethane bead access from the interior.

When you say the two rollers can't be trusted are you referring to the cup being pulled off the glass or the rollers have an issue?

I'm always available to discuss my products. Nobody else answers my phone.

To answer Ted's question about fishing line use, it is what is being offered already. You may find it hard to locate fishing line in the breaking strengths required for cutting urethane. Not as many uses at that strength so expensive to get because they don't make as much of it.

Yes, I would agree that I could be doing something wrong, nobody's perfect. Yes, the apex does come off and when it does it can do damage. I do not want to worry about it ever coming off. The bot never ever comes off, even without a angle cup. It may slide once and a while, but I can count on it never popping of. In this game it's all about the angles and how to get the best one. As stated before, it's too big in a lot of places down by the dash. The lever hinders me getting the best angle so I have to use a stronger line to pull thru them corners where the apex won't/can't give me the angle I want. I use it on 90% or more of the jobs I do. I absolutely love this tool! A must have in my opinion. Thanks for the conversation!!

Mike

A true professional is one that is constantly learning. I am a true professional every time I get feedback from my customers. Thanks for the kind words and never hesitate to call me out on my products for a conversation.

I'll look into the suction cup / pump suggestion as I do agree, the lever becomes an issue down low on some vehicles. Problem with the change would be cost of adding the pump to the part.

Still learning everything I need to know.

Rick

Yep, 22 years in and still learning. We all want to be better. I appreciate your openness to discuss & I will contact you soon and would like to explore this conversation a little deeper.

This is helpful to anyone when using cord or wire on a tensioning device with pulleys either attached to the winder or seperate.
Those with the pulley attached to the winder have the forces applied to the winder itself, those using a seperate pulley system the forces are applied to the pulley fixture.

http://www.ropebook.com/information/vector-forces/angular-vector-forces