Using a Shop Vac to pull string thru a Conduit?

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  #1  
Old 06-21-10, 07:17 PM
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Using a Shop Vac to pull string thru a Conduit?

I posted a thread on replacing AT&T Cat 3 with coaxial cable, as things have turned out I may not have to. I have another 2 inch conduit that was originally going to be used for coaxial cable, I had called Comcast in 2000 and they told me that I needed a special coax to use there service, they quoted me a price of $900.00 bucks for the cable. I was running the conduit for the phone, electricity, and cable. I put 600lb line in all three conduits, electric went in ok, phone went ok, I got Direct TV so I did not worry about the cable. In 2005, I decided to put in coaxial cable thru the conduit, I bought the cable, attached it the pull line and it snapped 30 feet in, at that point cable was not in my future. Talking to a tech at Hometech, he told me that I could put a new pull line in by using a Shop Vac and kite string. The question is I have to pull the kite string 530 feet thru the conduit, what kind of Shop vac do I need.
Thanks
Gregory
 
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  #2  
Old 06-21-10, 08:55 PM
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Any kind will work so long as it has strong suction. The trick is to seal off the vac hose end where it meets the conduit . . . a poly trash bag works fine. In other words, you donít want any air sucked in that is not coming from the conduit. A guy at other end of conduit cupping his hand over the conduit in an on/off motion is sometimes helpful.

Your conduit first needs to be free of water or else the wet string will be harder (or impossible) to get through. You can suck out any water if you have a wet vac. If you donít have a wet vac, you can blow the water out using a lawn power blower.

530 ft. is a long run but I think the shopvac technique should still work. If it doesnít, one guy using a power blower on one end of conduit while other guy is at other end with shopvac might help get the string through. On shorter runs, Iíve just used a power blower by making a small funnel (like a small umbrella) at end of string so that it catches the wind passing through the pipe.
 
  #3  
Old 06-21-10, 10:49 PM
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I tried a cheap Shop Vac model I bought at Lowes for $29.00 bucks, it says 5.5hp but I doubt it. I was alone so I tried Duct taping it the end of the conduit, I went to the other but did not feel any type of suction, the seal was proabley bad. HD a has 6 hp commercial type for $129.00, I wonder if that will do the trick.
Rob if the conduit has water, will the vac pull it out?
Thanks
Gregory
 
  #4  
Old 06-22-10, 04:17 AM
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I have had better blowing string through conduit than trying to suck it through. I tie a foam ear plug on the end of the string to help it catch more air and use an electric leaf blower to blow it through.
 
  #5  
Old 06-22-10, 08:49 AM
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Hi Greg,

When I read your OP, distance and having an existing pipe (i.e., water or sediment collected in conduit) cast doubt in my mind as to whether this suction technique will work. Iím not saying it wonít, but just not sure.

In situations on my property, the longest run was around 300 ft. whereas yours is nearly twice as long. Iíve always installed a line through conduit shortly after install so water has not been an issue. Iíll mention some things Iíve done in past, and youíll have to improvise based on your situation.

I use #18 twisted nylon like you buy at HD/Loweís (500 ft. roll). Kite string is thinner & lighter . . . not sure if this is an advantage or disadvantage since the suction has less to grip. Give yours a try since you seem to already have that.

I donít think youíll ever suck a string through if it gets wet as it will either sink when waterlogged or want to cling to the inner wall of pipe. So to your question, I would first try to get the water out if thatís relevant. The degree of difficulty is whether the terminal ends have bends and the length of risers. Assuming a depth of at 18 inches for the conduit, I donít think a shopvac will lift the water out of the riser if trying to do so at end of riser pipe. Recently, I had to pull a new Cat5 cable to my gate telephone entry system . . . fortunately, I was able to pull in a string using the faulty cable . . . however, the conduit was full of water and sediment, and I used a leaf blower to get most of it out but some still remained (it didnít matter in that case). You might try improvising the hose end of your shopvac {preferably a wet vac} . . . I purchased small vac attachments that fit the large hose . . . one is an adapter piece allowing the smaller diameter attachments to fit. If you had an adapter, you might try jury rigging a piece of flexible hose onto the adapter so that it can be inserted down the riser and into the conduit (make darn sure it is well secured as you donít want it to come off inside pipe). If one end is lower than other, suck from the low end as the water will flow in that direction.

Back in the 70ís, I used to work on an underground cable pulling crew for an electric utility. Everything we worked with was much larger in size, and our equipment was more powerful. Perhaps youíll spot a tip that you might be able to adapt to make your situation work. When working in manholes, the duct banks had a minimum of 4 inch pipes, and usually 6 inch. Since the manholes were deeper underground than the water table, the pipes often leaked water although they were roughly level from manhole to manhole. To overcome that problem we had a small, very light flotation ball which the string was attached to, and we would push that down the pipe with a strong force of wind . . . you might be able to cut a piece of cork (like from a wine bottle using a needle to push through it to secure your string) to help float your string if unable to get the water out . . a string that is water resistant might lessen friction (e.g., light weight, braided fishing line that floats on top). When water was not an issue, we had this device that looked like a badminton birdie but without any holes in it. The strong wind had a much bigger surface and would sail this device to the other end of pipe . . . some were in the range of 1,000 ft. runs, manhole-to-manhole. Since we didnít have bends in conduit to contend with, you may have to use a fish tape or piece of wire to fish it out if you can get it to the opposite bend but wonít lift out of the riser. Before posting, I saw Pilot Daneís suggestion of using a foam ear plug . . . thatís a clever idea as it also floats. . . the more wind that can go into a cone, the more it will tend to move it along.

I would say give it your best shot to see if you can get the string through based on whatís workable for you (and amount of time your willing to spend). I think youíre going to need yourself and another person to assist. Given the distance involved, your chance for success may improve by using a blower on one end of conduit, and a shopvac at other end. It is critically important to seal both ends very tight.

If you canít get it through, youíll be able to do so w/ a steel fish tape. The problem is that most homeowners donít have a tape that long, and many residential electricians donít either. Since fish tapes arenít cheap, stringing together 6, 100 ft. long spring-steel wires becomes a somewhat expensive proposition. Should you decide itís not worth the effort or just canít get it done, here is the cheapest 100 ft. fish tape I could find . . . 100 Ft. Fish Tape . . . you would be looking at around $130, including taxes for six. This might give you a way of comparing the cost of having a pro do this vs. DIY. Usually cable companies sub this work to independent cable contractors . . . if you can identify such contractor, you might want to get a price before going too far as it may not be worth your time and out-of-pocket costs.

In searching info on fish tapes, I came across this commercial Vacuum/Blower Power Fishing System for a mere $1,300 . . . Vacuum Power Fishing System, GL-690. Your job would be fairly simple to do if you could rent this machine (doubtful) or knew someone having one.

Good luck.
 
  #6  
Old 06-22-10, 12:40 PM
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first off, forget the kite string and use fishing line...much stronger. Get a dense sponge and cut circular piece out that's just smaller than the ID of the conduit. Get a piece of sandpaper or thin cardboard backing and run string thru small hole in sponge, then thru cardboard and tie off using something that will keep parts together (bread tie or little plastic piece). Then get the vacuum after it. I used this method to feed string thru conduit for pool power feed and timer. Worked great. Once you get the fishing line fed thru, tie on the nylon pull string as Rob mentioned.
When you pull the coax in, make sure to loop the string around the cable starting at least a foot back, then make more loops that tighten on the jacket when pulled. Keep tension on these loops as you wrap w/electrical tape.
Keep in mind you may need to break conduit halfway to get this job completed. 500' is a long way to pull if you have any hard 90's in the line.
 
  #7  
Old 06-22-10, 04:15 PM
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Guys,
I want to thank all for the replies, the conduit is down 42-48 inches, then a 90 degree bend running down hill to another 45 degree bend the 300 feet to another 45 then 100 feet to another 90, 5 feet till the last 90 that leads up and out at the pole. I ordered 600 feet of 220lb kite string, I was thinking to attach it to a pin pong ball, then with an Echo power blower pushing and a strong Shop Vac pulling I might have some success. But- there always a but, what if there is water in the pipe ?
Thanks
Gregory
 
  #8  
Old 06-23-10, 01:20 AM
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There is one thing you have to becarefull when you run the stringline first time before you do that run the pipe with compressed air first and expect to see the water fly out of the conduit which I have see it more than once sometime it can go up a bit of heightwise so do that first but you will not able get 100% of water out of it so expect some left in there.

For the rest of details the other members here did explain pretty much right on the spot.

But when you pull the cable do not pull too hard otherwise it will snap and also use plenty wirelube that will help a bit.

And have a helper push it down while someone on other end pull the cable up thru the conduit.

Merci.
Marc
 
  #9  
Old 07-02-10, 03:57 PM
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conduit filled with water

Hi Everyone,
My wife and went to work on seeing if we could at least get the kite string through the conduit. We hooked up the shop vac at the house end and I went to the street with the blower. We started the the shop vac to make sure we had no air leaks (we wrapped a plastic bag around the connection joint to seal, worked as instructed) when the shop vac was turned on, the hose connected to the vac started to compress, I went to the front and started the blower put it to the other end of the conduit and let it run for a minute, I called my wife and asked her if she could hear anything, she said no. I told her to turn on the shop vac and I would turn on the blower at the same time, we ran them together for 3 minutes straight, when I turned off the blower after 3 minutes I could hear water gurgling in the conduit. I came back to the house, checked inside the conduit, empty. So what are my choices now. I'm wondering do I go to Home Depot and get a stronger shop vac, I do have an air compressor, it's a 6 hp, 135psi, 30 gal model. Any ideas at this point would be greatly appreciated.
Thanks
Gregory
 
  #10  
Old 07-02-10, 04:49 PM
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if its been in the ground for 10 years chances are good enough water and dirt in there to clog it

how about going to the halfway mark and digging it up , cutting it installing a pull box and go from there
 
  #11  
Old 07-02-10, 05:55 PM
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It'll cost you 100-150 dollars but go rent a big air compressor, 125 CFM or so and 25 feet of 3/4 inch hose. Connect the hose to the conduit and compressor and build up to 100 psi. Open the valve on the compressor wide and watch the water and crap shoot out the other end of the conduit.

You cannot do this with a small compressor because it is the high volume with the pressure behind it that will blow out the water and crap.
 
  #12  
Old 07-02-10, 09:40 PM
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At this point I cannot start digging at the midpoint because it's running under 6 inches of asphalt and a foot of gravel and process. Now using a heavy duty compressor sounds like a solution, just a couple of points, are these electric or gasoline powered. How big and how do I get it home.
Thanks
Gregory
 
  #13  
Old 07-02-10, 10:17 PM
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Those are pretty serious duty air compressor and they can be either gaz powered or diesel powered { most will be diesel units } and they are trailerbale they will weight in about 2500 to 3500 lbs range.

The 125 CFM is most common one they will charge by running hours IIRC.

I have my own portable air compressor but it much bigger one it is 400 CFM { that I used for to start up big gaz turbine generators ( the engine size is simauir to 747 turbine engine )}

But I really recomeond that you ramp up the air supply slow if you open up very fast few things can happend one is you will blow the conduit apart or water or dirt will come out the conduit like shotgun once you get up the running speed so on the open end make sure no one standing near by the open end of the conduit so they don't get hurt one way or other.

The last time one guy have to use my 400 CFM unit they did use the nerf ball to clean out the concrete pipe and when it went out it did make a dent on the truck door

Oh yeah get the ear muffs as well or ear plugs they will be loud as Heck !! and hang on the hose once the valve is open up to wide open postion it may push you back if not carefull.

Merci.
Marc
 
  #14  
Old 07-02-10, 11:53 PM
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There is no way to get a piece of machinery that big in and out of the property (no place for the vehicle to turn around) How big a vacuum do you need to suck the water out ? I do not think the one I'm using has any power.
Greg
 
  #15  
Old 07-03-10, 12:19 AM
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you can park the unit on the street and get few section of air hose they can go quite a way if you have to.{ get few 25 or 50 footers they can cover pretty good distance.}

The vaccum will do not much good in the conduit at all you denfity need heckva good air pressure to blow all the gunk and water right out with good flowage once you have both pressure and volume of air movement you can able get the conduit pretty much clean out that way.

The last time I have to clean out 4 inch conduit full of water it almost like geyser comming up the ground it did hold over couple hundreds gallons of water the ground shoke a little but when the water really move they come up pretty fast.

Merci.
Marc
 
  #16  
Old 07-03-10, 01:07 AM
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A 125 CFM compressor isn't all that huge, most are on two wheels can be towed behind a 1/2 ton pickup. The compressor you see working a jackhammer on the street is often a 125 model.

Marc IS correct that IF the conduit is really packed with dirt the air could blow it apart but that is really a worst-case scenario. If you can't get the compressor close and need extra lengths of hose then it is best to go up a size (diameter) on the hose. It is the volume that does the work more than the pressure. And yes, it IS noisy so hearing protection is a must.
 
  #17  
Old 07-03-10, 04:43 AM
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Hey Greg,

From OP, I think you have 3, 2Ē conduits installed together. One is used for electrical, another used for telephone, and third is the one currently involved in which you want to install a coaxial cable. Having each cable in a separate conduit is the ideal solution as itís less costly and disruptive should a cable go bad in future.

Given the problems youíre running into, have you considered running the coax and telephone line within the same conduit? In looking ahead, have you thought about switching to Comcast for telephone service possibly making the existing telephone not necessary (assumes that service is available to your area)? Iím not sure what kind of response you might get from Comcast, and that should be discussed prior to doing it. Iím also not sure who will claim ownership of this coax cable . . . you have a strong argument that you will own it since you installed conduit (or had a contractor do it for you) and paying $900 to Comcast for the cable . . . Comcast may argue they own cable, and theyíre just asking you to pay a contribution toward its cost . . . I donít know what has been agreed between you and Comcast. If thatís not acceptable to Comcast and they provide telephone service, then you may want to weigh the hassle factor and cost of renting HD air compressor against taking telephone service from Comcast temporarily with plan to switch to your preferred telephone provider later . . . when switching, the provider will often quote a predetermined installation cost, and let them go through hassle of installing their line through clogged conduit. While you may have good reasons for rejecting this idea . . . if itís something you want to explore, then try to remove some unknowns by calling your existing telephone provider as a ďnew customerĒ, and see what they say charge would be to install a new phone line through your existing conduit. One thing to plan for . . . telephone cable crew may get to site, and take what they think is easy way out by direct burying their cable if not bringing machinery to resolve conduit clog . . . you might want to have a fall back plan of staying w/ Comcast until telephone line is installed to your satisfaction, and using that as leverage of demanding telephone line must be pulled through conduit or youíre not switching.

If you go route of heavy duty air compressor (best option for clearing the clog), after clearing the line, make sure you use this machine to blow in your string line (probably obvious).

One other point, a few yrs. ago I experieced weak cable signal as I dead-end on the their line . . . Comcast supervisor really pushed me into installing a commercial sized coax to my home by offering it free of charge.
 
  #18  
Old 07-03-10, 12:26 PM
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I want to thank all for the quick responses, United Rental has a compressor for rent, heres the link United Rentals - Find Equipment - Air Compressors & Air Tools - Sullair 110 CFM 110CFM Towable Air Compressor.
It's a 110CFM machine, I'm thinking that should have enough volume to blow it out, I will find out the price on Monday, delivery and pick up should be reasonable if they can use a pick up, I've got a Honda CRV which has 1000lb towing capacity. Rob in an earlier post I was thinking about using the AT&T telephone cable to pull in a combination cable/telephone line into the house, but I need to run RG11(because of the distance) to the house and nothing in combination come in that gauge. Actually RG11 is not as readily available as I thought it was. LCom which is based in Mass. does not even carry it. As I sit here thinking, the conduit is Schedule 40, grey, very thick, and even though it's been sitting in the sun for the last 10 years extremely durable, I can glue a 45 on it and blow everything away from the house, so I could do it from the street. Please let me know what you think.
Gregory
 
  #19  
Old 07-03-10, 05:09 PM
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The rental compressor should be powerful enough.

I read your other thread . . . I now understand why that idea wonít work.

I agree w/ furd & Marc about safety issues on blow-out side. Also be safe on hose side as there will be significant back-pressure until clog is cleared, and you donít want a loose hose under high pressure whipping around . . . wear eye protection.

Take a close look at this link for more detail http://www.ur.com/files/corp/catalog...ompressors.pdf. Confirm w/ rental guy what type trailer mount is on compressor to avoid lost time on day of delivery if not compatible with your Honda CVR hitch. Explain to rental guy how you plan to use to make sure there is no surprise at compressor hose end in mating it up to your 2Ē PVC. Also, will pressure be regulated at machine or hose end . . . youíll probably want to control compressor hose going into pipe given your strength . . . if working w/ wife, make sure you and her are comfortable doing this together if she is having to do anything at compressor.

I would want to end-up w/ at least a 3/16Ē pull line given long distance and number of bends involved. I would want that done before returning compressor as you donít want that expense again. When ready to pull cable, use a cable pulling lubricant or liquid soap as that will make for an easier pull and help avoid damage to cable skin . . . have a short piece of pipe handy so that pull line can be wrapped around it and gripped w/ both hands to gain leverage. Iíve set-up two ladders with a pipe between them in order to easily feed cable off the cable reel . . . youíve mentioned hilly terrain, and ot would be easier to pull downhill if possible (while not certain, I think youíre going to be using compressor to blow out clog going uphill).
 
  #20  
Old 07-04-10, 12:08 AM
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Really I recomend that you run the air hose up the top side and let it blow downward thru the conduit it make easier to push out the gunk out as I mention start up low flowage first to build up the pressure once you get stable then crank it up you will feel the diffrence and yeah of course you will heard it.

Make sure you keep anyone away from downhill side of conduit and get something to deflect it if necessary if you are pretty close to the POCO post. { trust me on this one the debries will kick up pretty high once you get good flowage going.}

For some reason if not blow thru stop right there and reverse the air flow and try to loosen up debries by changing air location real breif then switch around it will useally clear up by that time.

And ask the rental centre for string line blower gimzo so it will shoot the " mouse " with hevey string in the conduit and once you start shooting it keep the air valve wide open until the " mouse " come out complety on the other end of conduit.


Merci,Marc
 
  #21  
Old 07-04-10, 02:39 PM
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The pole on the street side that the conduit exits on and the one close to the 6-inches to a foot from the house are almost equilateral in there elevation, with the low point being in the middle. I have not dealt with United rentals for 4 or 5 years, do they usually have everything needed for the compressor ? I'm wondering what else besides water could be in the conduit, both conduit are 2 feet above ground level. I going to get 1800lb test Mule Tape to pull the RG11 cable through, it's $95.00 for 3000 feet, it's supposed to be a lot easier getting things through with it. I was thinking to control the refuse thats going to be coming out by using a 45 or 90 to blow it away,from the house, good or bad ?
Thanks
Gregory
 
  #22  
Old 07-04-10, 03:48 PM
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to control the refuse thats going to be coming out by using a 45 or 90 to blow it away,from the house, good or bad ?
since the whole point of the big compressor is to get the job done why put more resistance on the run ?

I would drape a tarp a couple of feet over the end to direct the flow away once it exited the pipe
 
  #23  
Old 07-06-10, 09:49 PM
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I stopped the United Rentals close to home, they had this one instead of the 110 - United Rentals - Find Equipment - Air Compressors & Air Tools - Sullair 185 CFM 185CFM Towable Air Compressor

The cost is $125.00 a day, hoses are $10.00 a day, I'm going to order the mule tape this evening and wait for that to get here.
Greg
 
  #24  
Old 07-20-10, 02:25 PM
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Hey, just wondering if you got your line through, I work for a cable company up in Ontario Canada, and just wondering what type of cable you planning on using for that distance..?

If your using RG6 or RG11 neither will be able to carry the signal that far and you will get a horrible picture or none at all you need to use TX15 which is pretty much mainline....

Cheers....
 
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