installing string in PVC

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masterinbama

Senior Member
I have also found when blowing string in PVC stub ups it's easier to drill a hole just big enough for your string in the side of the pipe. That way you can get a good seal on your compressor hose. Drill it near the end of the pipe and the TA or bell end will cover it.
 

renosteinke

Senior Member
Location
NE Arkansas
Cute pic, bama!

That's a good point, about gettig a good seal for the air compressor. I have a modified air gun nozzle with a cork over it for the seal. Naturally, I had to do extensive research at fie restaurants, searching for the perfect cork. :D

How do I feed the string? I cheat. I use "tampons." That is, I use store-bought gizmos that consist of a foam plug and a coil of very fine string; the whole thing goes in the pipe. I just secure the loose end at the start. The complete package looks like, you guessed it, a tampon. I think they were first developed for use with CO2-powered guns.

Anyway, this fine string is then used to pull back a proper twine, or string.

I used a 'car detail kit' to cobble together a similar tip for the vacuum far end. The key here is that your 'cork' be soft enough to force into the pipe and hold. A few layers of splicing tape works well. You start up the vacuum, then go to the feed end and shoot the line.

One last detail: Make sure the glue in the pipe is dry! Completely dry! A string that gets itself glued to the inside of the pipe is no fun. You might even want to use the vacuum to draw air through the pipe for a few minutes, just to be sure. With little air flow inside the pipe, the glue can remain wet for quite some time.
 

masterinbama

Senior Member
On large underground runs I prefer to install the poly line as I go. Then I replace it with a 1/4" or 3/8" poly rope when I get it all installed. We quite often install 1000' runs of 5" for the utilities and a run that long can be a booger to suck or blow a string through. I tie the line to a 3' piece of 1/4" rod with an eye bolt on each end, you can throw it through a 10' stick of 5" easily and it will bend enough to push through your 90's.
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
On large underground runs I prefer to install the poly line as I go. Then I replace it with a 1/4" or 3/8" poly rope when I get it all installed. We quite often install 1000' runs of 5" for the utilities and a run that long can be a booger to suck or blow a string through. I tie the line to a 3' piece of 1/4" rod with an eye bolt on each end, you can throw it through a 10' stick of 5" easily and it will bend enough to push through your 90's.

We have to feed the string as we go sometimes also. we use a 15-20' piece of fishtape.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
I have also found when blowing string in PVC stub ups it's easier to drill a hole just big enough for your string in the side of the pipe. That way you can get a good seal on your compressor hose. Drill it near the end of the pipe and the TA or bell end will cover it.

Thanks for answering my question before I asked it. (Namely: "If blowing, how do you not trap the string between the pipe and the vaccuum hose?")
 

Fulthrotl

~Autocorrect is My Worst Enema.~
How do I feed the string? I cheat. I use "tampons." That is, I use store-bought gizmos that consist of a foam plug and a coil of very fine string; the whole thing goes in the pipe. I just secure the loose end at the start. The complete package looks like, you guessed it, a tampon. I think they were first developed for use with CO2-powered guns.

Anyway, this fine string is then used to pull back a proper twine, or string.

they are called jet line, and they come in 1/2" and 3/4". looks like dental floss,
feeds from the center of a spool, with a sponge on the end.... come in white boxes
of 20..... 1/2" are 200' long, and 3/4" are 300' long....

now... where the hell do you buy them? i can't find them anywhere in so calif.
and it's making me crazy. well, crazier.

nobody even knows what they are here, they just look at you like a cow when
you ask for them...

the last time i used them was in 1985, on a hotel.. we blew all the phone
home runs in about 30 minutes.. it was awesome. first blast from the compressor
is to clear the line, second is to blow the string... goes 100' in about a second and
a half.....
 

elecold

Member
the last time i used them was in 1985, on a hotel.. we blew all the phone
home runs in about 30 minutes.. it was awesome. first blast from the compressor
is to clear the line, second is to blow the string... goes 100' in about a second and
a half.....

I have used this type of compressor before to blow lines. But I wonder if a small compressor has enought air flow (CFM) to do the job fast. What type of compressor are you referring to?
 
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