Metal dust okay for kids?

This seems like a no-brainer but I'm running out of options. I ran an "aircraft grade" harbor freight braided steel line in the basement as a zip line for a week but we noticed metal dust coming off it constantly. So, assuming it was killing the children, I took it down. Since then I've tried 5 kinds of non-metal rope that all stretch too much to work, including Kevlar yesterday. 
 

If they're gonna have a zip line it's gotta be metal, apparently. Any other thoughts on how to accomplish this?

Can you grease it? I imagine that'd both cut down on the amount of dust created and then also the amount of dust that gets airborne. Then occasionally wipe it to collect the dust. Kids may go zippier, too, make it a win-win for all. 

From a health standpoint, any particle can be nasty on account of its geometry, but steel is mostly made up of okay stuff in our bodies already like iron and carbon. Synthetic ropes would probably be worse. Just a guess though. Also, composites are notoriously nasty. I'd be most comfortable risking a basic steel. 

I'm no expert on basement zip lines, but what is sliding down the cable?  Some kind of trolley?  Steel rollers?  If so, any way to use nylon, delrin, plastic rollers? 
 

Or is the line shedding just from flexing?

Perhaps finding some high quality unplated cable and hardened pulleys from an industrial surplus type place would be in order? The HF aircraft grade wire might be flaking it's nickel plating off.

Also be sure to look at where the cable could rub on something as possible sources. The pulleys might be too soft too.

Yeah, my statement was directed towards basic steel. Nickel is bad, mkay. 

Only let them play on windy days?

Don't worry, the radon in the basement will cancel it out. 

Old sailboat shrouds.  Braided stainless and more than strong enough.  While perusing used boat part posts find some harken blocks(pulleys).  They have extremely tough rollers and should take the load.

Plastic pulley on the handles?

Hay those kids have to get the Iron somehow.  

My dad used Mercury from thermometers he broke to shine up silver dimes back in 1945 and he daily smoked cigars from age 18.  He lived to 82.

Dont sweat it. 

Datsun240ZGuy said:

My dad used Mercury from thermometers he broke to shine up silver dimes back in 1945 and he daily smoked cigars from age 18.  He lived to 82.

Dont sweat it. 

Yeah, but back then, people were tough.

Don't they have metal cable enshrouded in plastic? If you're running pulleys on the cable they should still work just fine.....

I work for a testing lab that does VOC and particulate testing, you don't want to know what we breath in already, I would keep new dangers to a minimum. 

My great grandfather worked at the Crane Company in Chicago as a Foundry Man for 47 years (1910-1957).  He also rolled his own cigarettes and smoked them into his late 70's. 

I imagine he never once saw a mask and I wonder what he breathed in all those years?

In reply to porschenut :

I was going to say get some dynema or similar sail line and be done with it. I use 1/4" for steering on my race-boats. No stretch and pretty resistant to abrasion. Thinking half inch would support even the most rotund zip line participant over a short distance . 

for lubricating it, I wuold use a wax rather than an oil or grease. 

others are probably giving better ideas for replacement lines.

Thanks for all the replies- helpful or not :P

I've looked up stretch-resistant line and tried dynema this in particular and here's the braided Kevlar which is also supposed to not stretch. They both kept stretching. Maybe if I did it enough they'd eventually stop, but my fear was that by then I'd have damaged the end connections/loops. 
 

Again, this is in addition to the "aircraft grade" braided steel line from HF and this nylon stuff. Pay no attention to the gauge linked. I got whatever's safe enough. 
 

So steel seems like the way to go. I'll try wax, I guess??

In reply to P3PPY :

As a guess, I'd go with a heavier fluid like vasoline or grease. Cables will also be shifting internally when they flex, so something that can get into the fibers may cut down on that internal dust. Dust will also cling to a grease better than a wax, so, even if you don't reduce the amount of particles created, you reduce the amount that gets airborne. 

It isn't too different than our own snot trapping dust, just you are doing it at the source. I just noticed this exact effect on my go-kart. The chain lube really holds all the aluminum from the sprocket, and you can see the shimmer when you wipe a finger across it.

Just tell the kids not to grab the line, haha. 

In reply to cyow5 :

It's only a 25' line with the only drop being the droop in the middle- would you expect grease spray from the pulley running over it? It's carpeted down there and that's another concern. 
 

Ya know, I've also wondered about a slack line or long ratchet strap -- surely they don't stretch too much 

In reply to P3PPY :

I was more concerned with any grease dripping down, so I didn't think of flinging. Nylon coating would trap any dust, too, and would be more durable than wax. Maybe get a can of nylon grip coating and paint it on?