Can I give a string Viagra?

December 26, 2006 7:03 AM

Afetr years on dial-up we almost have broadband, the trench is dug, the cable guys are coming, there is only one problem. Help me get a string through 200 feet of flexible pipe.

We are going underground because all our other utilities are underground and a wire would be an eyesore. We can't dig in the old trench because there is a risk we would sever the exisiting pipes. We need the string to pull the cable through the new pipe. We chose to use the flexible pipe rather than 2" PVC which would need a lot of gluing to make it watertight. I know there must be a way to do this but nothing is coming up.

posted by Xurando to home & garden (24 comments total)

Tie the end of the string around a piece of cloth, or something similar, then suck it through with a shop vac.
posted by kableh at 7:14 AM on December 26, 2006

Magnets? Tie a magnet to the end of the string and run another magnet along the outside of the pipe, thus pulling the string along through the pipe.
posted by amro at 7:15 AM on December 26, 2006

Or, a magnet and a piece of metal.
posted by amro at 7:18 AM on December 26, 2006

rather than string, I'd suggest monofilament fishing line. It's generally stronger and thinner than string. How large a diameter is the tubing?
posted by cosmicbandito at 7:20 AM on December 26, 2006

You want a wire pulling rod. here is a paid search result from Google by way of example. I don't know what these things typically cost or if it's possible to rent them from somebody, but that's what you want.
posted by willnot at 7:22 AM on December 26, 2006

You'll need to firm this up with an electrician or with someone from the electric or telephone company who do this all the time, but I can give you a rough idea. Tie the string to a wad of paper (or perhaps a rag?) so that it makes a snug but moveable fit inside the pipe. Lay out enough string to make it all the way through. Snug a powerful shop vac to the other end of the pipe and suck the wad and string through. Later, the utility will pull the cable using the string. That's the outline, but the professionals you consult should be able to give you tips that only they know. On preview, what kableh said.
posted by Hobgoblin at 7:22 AM on December 26, 2006

Rent a fish tape.
posted by buggzzee23 at 7:25 AM on December 26, 2006

Know anyone who owns a ferret?
posted by bondcliff at 7:34 AM on December 26, 2006 [1 favorite]

Actually, an electrician I know really does buy or borrow a mouse or gerbil every once in a while for this very job. He ties the string around its waist, attaches a tiny LED, and it runs right through.
posted by glibhamdreck at 7:51 AM on December 26, 2006

is the tube/pipe burried yet?
posted by quadrinary at 7:56 AM on December 26, 2006

Can't you run something stiffer than string, like electrical wire, or picture frame wire?
posted by jaimev at 8:25 AM on December 26, 2006

The phone engineers in my street did this by tying a rope to a big rubber missile buoy thing that they blew along the pipe compressed air. You might be able to rig something similar together.
posted by cillit bang at 8:40 AM on December 26, 2006

Yeah, I’d bet you could push a 20-gauge wire through without much trouble. Hardware stores usually have spools of annealed or galvanized wire for less then $5.
posted by lemhuxley at 8:41 AM on December 26, 2006

I second the vacuum. Tie a plastic bag to your pull string, shove it in one end, and vacuum the other. It'll go around almost any bend.
posted by notsnot at 9:11 AM on December 26, 2006

When you figure it out, pull twice what you need and leave it in the pipe for any future work.
posted by odinsdream at 10:13 AM on December 26, 2006

Ditto buggzzee23. I've done more than my share of (inside plant) cable work, and a fishtape is the only way to go here.

Feed the fishtape into the conduit. When it comes out the other end, tie the string to it, and reel it back in, taking the string with it. My suggestion would be to use the fishtape to pull a light string (like heavy fishing line) and then use the fishing line to pull your strings.

Also ditto the comment that you should pull twice as much as you need. Cable does deteriorate (I've had to replace rat-gnawed Token Ring cable before), and you'll need to pull another run eventually. The suggestion I would make here is to pull 2 or 3 separate lengths of pull string at the same time. This way, you can pull another cable run any time you need to, and still have a spare to pull more string through.

Finding a 200 foot rental fishtape may be a bit of a challenge, though. Your best bet there is to call an equipment-rental outlet that markets more to tradesmen than homeowner/DIY types.
posted by deadmessenger at 10:31 AM on December 26, 2006

The other alternative on the pull-string is to pull in a string that's a little longer than twice the run of the pipe, and leave it coiled up at one end. Optimally, you should put something on each end that's larger than the pipe.

Tie a knot in the middle, so you know where to tie on the wire you're going to pull.
posted by baylink at 1:04 PM on December 26, 2006

Schedule 40 PVC comes in 20 foot sections. I've built water lines for my proerty more than 200 feet long in less than an hour with a small 5 dollar jar of primer/glue. It's simple as hell. And it'll hold up better.
posted by docpops at 1:14 PM on December 26, 2006

By the way, docpops is right on the flexible. It sucks, while rigid is easier to pull things through. My experience with condiot is that no matter how watertight you make it, variations in humidity will fill it up in a year or two with water. Taking this in mind, you want the cable to be as unmolested as possible - no tears in the jacket whatsoever. To do this, you're gonna want to use rigid pipe. Actually, I believe conduit is cheaper than plumbing pipe, and it's made for the job. Once you get it laid, try the vacuum trick, and you'll have the pull string through in a matter of seconds. I've done this a million times on carwashes for sensors and whatnot.
posted by notsnot at 3:03 PM on December 26, 2006

Everyone else is right - you should use solid conduit, 2" is probably too big, fish / blow it through, etc.

But two more things:
Firstly, if you'd used 20mm or 40mm solid, you could easily push CAT-5 or coax through 200' (it's even easier to push it through 20' lengths then assemble it).

Secondly, don't run several hauling strings through it. Run one (2 at most), then when you haul your cable in, haul another. Otherwise you'll just tangle them.

p.s. if the cable guys are actually hauling the cable from the street to your house, they'll probably have a nice long fibreglass fishing rod for just this sort of thing. And they'll hate you for using flexible conduit - too rough to push through easily, and everybody who's ever used it makes under-radiused bends.
posted by Pinback at 4:42 PM on December 26, 2006

Smooth-walled flexible pipe, like used for in-ground sprinkler systems, is ideal for this. It's rated for direct burial, it's easy to suck a mouse through, and it's stiff enough to discourage overly tight bends.

Even if you've already installed the corrugated stuff, the vacuum cleaner trick is still possible. Use the thinnest, lightest line you can find. Fishing line is fine, you'll use it to haul in a real pull-string later. If you find that the vacuum cleaner isn't working, assist it with compressed air from the other end at the same time.

As for pull string, get the light cheap stuff that comes about 6500 feet to a bucket. I've seen small "wet ones" style containers with 500 feet, which should be ideal. Use the fishing line to pull the string into the conduit, then attach your cable to the string and continue pulling, so the rest of the string runs alongside the cable for future use. Good luck!
posted by Myself at 7:09 PM on December 26, 2006

I've set up networks before, and we always either use a fishing pole or a mouse with a string tied to its leg, and the other end of the string tied to the cable.
posted by fvox13 at 9:30 PM on December 26, 2006

I would see no trouble using a portable compessor to blow the string through if you feed it at a managed rate(and have acsess to a compressor).
posted by Iron Rat at 10:01 PM on December 26, 2006

Thanks everyone. The fishtape worked perfectly. Unfortunately the cable guys never showed up but that's another question for later.
posted by Xurando at 12:34 PM on December 29, 2006