blowing string through conduits

[ohmhead]

We used co2 years ago. It would put a mouse through a hollow core door. Might not make it on the safe way to do things today.

Well what is safe today ? Heres what we use

GB still sells compressed air tanks its a complete kit we stopped using that system years ago its way to expensive and a waste of time .
and we used to get are compressed air bottles from a welding supply house these will freeze up the water in the pipe becuse of the pressure in the compressed tank there no good .

They use these everyday in the electrical trade and its safe the high pressure is in the conduit and if you follow the OHSA safety rules on operating a compressor which is you must have a safety release valve on hose at unit air hose input meaning on compressor .
The air hose must be locking type meaning couplings tie wired thur hole type .
If you rent one just tell the company they must have this on unit its theres to install not yours by OSHA .

If for any reason the pressure exceeds a set volume the release valve shuts down unit automatically .

If the hose breaks it shuts down .

The nozzle we use GB sells these for compressors it has a adjustable throttle you start slow and adjust up to suite you needs .

This is a OSHA RULE and they have been on many of our job sites in the past as we were using this system during there walk thur inspection .

When you blast air into a 4 inch conduit all that high pressure gos inside and it fills up the volume of space in that conduit which is not like a 1/2 conduit you have some pressure at first but the when it comes out the other end 600 feet away it just flops out .

Now if you use it on a water filled conduit you get a 25 foot shower on the other end but pressure is not 130 pounds you can put you hand over the end of conduit and feel the minimal air coming out .

Its unsafe if your doing it unsafe .

 

[hardworkingstiff]

Now if you use it on a water filled conduit you get a 25 foot shower on the other end but pressure is not 130 pounds you can put you hand over the end of conduit and feel the minimal air coming out .

Saw a guy get a piece of metal buried in his hand holding it over the end of a conduit with air being blown in from a compressor.

 

[George Stolz]

Well what is safe today ? Heres what we use

How does the price of that compare with a shop vac?

 

[iwire]

How does the price of that compare with a shop vac?

Right in the same ball park.:grin:


But seriously we will borrow or rent run if we need to.

 

[Don S.]

You have not experienced true misery unless you worked on installing a duct bank of orangeburg on a hot summer day. Orangeburg, knob & tube, and friction tape. Those were the good old days?..maybe not!

 

[rt66electric]

leaf blower

leaf blower

I use my wife's leaf blower. Small, compact, CHEEP.

 

[ohmhead]

Well its alot more expensive but your not going to get any polyline in with out this at over 600 feet .

Not unless you like to spend lots of labor and waste time .

Not much air comes out with that compressor at the end of a run of large conduit it can hold a lot of air but once the mouse comes out its just a little bit of air you can feel it but it has no pressure after the mouse comes out .

Now short runs we use a vac .

We were kinda showing the OP different types of ways in commercial work and if you do commercial your going to one day need a air compressor like that we rent or use one on the job there is always one on site .

One more good method is to use two vacs one blowing and one sucking try it weve taking out lots of water that way and its good for 300 to 400 feet .

As iwire said we can always use someones air compressor on site and lots of times we do so its not a real bigg exspense you just need the nozzle and release valve if they dont have it .
I keep mine in the tool shed .

 

[Jnas480]

I used my wife?s Metro Dryer. (pet dryer)

This has two stage blowers on it and also has a heater. (only good cold days)

This you can get on e-bay or buy it from pet grooming supplies, it is a little coastly but it has one heck of a punch.

I also gone to a plumbers supply house and bought different Flex Fittings from 4' to 1 1/2 3" to 1 1/2 fittings to reduce and enlarge.

I also used the wet dry vacs with it. (Throw those foam mouses away and just use a plastic bag like a parachute in a pipe)

 

[jeremysterling]

greenlee string with an plastic bag at the end and a shop vac....

I agree that greenlee string is the best string. It probably cost more...