View Full Version : Pipe Thawing
05-22-2003, 05:23 PM
OK,maybe a dumb question here from somebody already in the biz but what is the correct procedure for using an arc welder to thaw pipes out?
05-22-2003, 05:29 PM
Arc Burn, the correct procedure is not to do it. I know people that do it in Canada and the first thing they do is get a million dollar liability insurance policy, cause it only takes one poor connection to have a large bon-fire( and permanently thawed pipes). But like I said we at Miller/Hobart do not recommend it.
05-22-2003, 06:41 PM
Miller/Hobart may not want themselves involved with thawing pipes but Lincoln Electric apparently does. They have a technical bulletin entitled “Thawing Frozen Water Pipes E695.1”. The bulletin describes the actual thawing procedures using a product of theirs called a “Linc-Thaw”.
In addition, many types of industries have used and continue to use Miller, Hobart, and Lincoln welding equipment at their plant sites to thaw frozen water, steam, caustic, etc. lines. In most cases, the plants themselves will develop their own thawing procedures independent of the welding equipment manufacturers or in the case of Lincoln equipment, incorporate it.
Regardless of procedures, circumstances, or equipment, liability insurance is an absolute necessity.
05-22-2003, 08:33 PM
Welcome to the forum, Seldom....your input is always welcome...there's new folks and even us old folks that can benefit from your experience. :)
05-22-2003, 11:14 PM
I do thaw pipes with welding machines but it really takes some understanding of electric systems to do it safely and I do have the bulliten from Lincoln but it really doesnt describe the problems and is merely a time/heat guideline. Most problems occur on city water systems which have several buildings on the same electric transformer. The main entrance to a home,, lets use this as an example,, has the panel bonded to the electric system. In this case, using an insulated tool I unbond the electric before I hook the machine to it. Because it is bonded and if there is a high resisance joint in the pipe you are trying to thaw the welding machine current may route via the neutral wire and then thru the ground bond in the neighbors house back to the water system. If it is a number 6 wire lets say running in a wall or wood it would become easily overheated by high welding currents and turned red hot, possibly in the wall of a neighbors home and a fire occurs. A DC amp probe would be of help for this, but they were not available when the first Lincthaw bulliten was out, so they wanted to sell a DC amp meter so you could keep an eye on actual current flow. I can tell somewhat by the machine sounds but often use a machine with AC and just use a clamp on meter to check too. Start slow untill you are sure of the condition of the pipeline,,, most proplems are with steel with threaded couplings that become corroded. Actually steel thaws better than copper but rolled copper doesnt have joints to fail. The resistance heated pipe causes a fine film of water to thaw and allows flow past around the ice plug. Water pressure on the line is a must and once a bit of flow starts again it melts the plug. And,,,, Yes,, no ins company wants to insure for this. And if the truth be known they are no help in education about why the problems occur and lots of operators dont really know how to do it proper, so that doesnt help matters either. And remember, this isnt as much of an instruction,,, just a general theory.
05-23-2003, 05:11 AM
It doen't work on my white water pipe. :mad:
05-23-2003, 05:45 AM
We do it all the time, only we use a General Thaw unit, it is designed just to thaw water lines.
110 volt unit with 320 amps and very little volts.
They make a couple of units that are both bigger and smaller than our however they work great.
Hobart Expert Rock
05-23-2003, 09:25 AM
HI SHELDON.............WELCOME ABOARD.........I CONCURE WITH SCOTTH MILLER/HOBARTS WILL NOT RECOMMEND IT.......... YEARS AGO HOBARTS ACTUALLY MADE A PIPE THAWING PIECE OF EQUIPMENT.......... WAY TO MANY LIABILITY ISSUES WITH IT.... WELL WE KNOW PEOPLE DO IT.............. BUT IT IS TOTALLY HAZERDOUS........... CONSIDER THIS IF I'M THAWING OUT MY NEIGHBORS PIPES WITH 400 AMPS AND MY KIDS ARE DOWN THE STREET SWINGING ON MY OTHER NEIGHBORS METAL WATER PIPES............. 400 AMPS AT WHAT EVER VOLTAGE WILL NOT BE A GOOD THING.................. OR GETTING A GLASS OF WATER FROM THE SINK..............JUST THINKING SAFETY HERE.........CONSIDER THIS WHY DO YOU THINK THE WATER PIPES ARE NOT GOOD GROUNDS IN YOUR HOMES... THEY REQUIRE YOU TO USE A 8' GROUND ROD NOW..........................................ROCK. ..:cool:
05-23-2003, 10:44 AM
I see how confusion gets started so easily. Miller/Hobart doest recommend it because of liability and there isnt enough money in it to make it worth their while. If they thought they were going to sell some machines for it they would. You prove a point I made earlier,, that most dont know how to do it and that is what makes it dangerous. You are probably not sposed to thaw your residential water pipe with 400A. Second, the hazard isnt with electrocution, its with starting fires. Now we can get someone as well respected as yourself say something that may be only partially correct and it can get taken as gospel and that starts the rumor mill. Incoming water pipes are intended to be the primary grounding electrode for the electric system and are required to be used for that and a ground rod is only suplimental, one reason is that in case of disconnection of the water pipe there is still an electrode in the ground. The grounding electrode system is not for clearing shorts,, only the ground wire back to the service entrance and hence back to the transformer is for that. There are stray voltages with potentials much higher than welding currents in the ground all the time, thats one of the reasons for the rods. We dont want to use water pipes to ground equipment for a couple of reasons,, 1, is that there is no good reaso to subject the piping system and anyone in contact with it to voltage from a fault,, and second, is that it makes for a round about path instead of a DIRECT PATH back to the panel. Thawing piping with machines isnt inheriantly dangerous,, careless thawing is dangerous,, just as smoking causes house fires, not really, its careless smoking, or driving, its careless driving or human error that causes accidents.
There is a short chapter on the subject of pipe thawing in the Lincoln "Procedure Handbook of lArc Welding", might answer some of the questions.
01-11-2004, 02:02 AM
Rock's right about Hobart used to make pipe thawers, I used one when I worked at Hobart Brothers to solder lugs onto the ends of battery charger cables. It was a set of tongs with carbon insert on the end of the tongs and then leads going to the unit. I used up to when I quit in 2000.
01-11-2004, 10:15 AM
Originally posted by Seldom
In addition, many types of industries have used and continue to use Miller, Hobart, and Lincoln welding equipment at their plant sites to thaw frozen water, steam, caustic, etc. lines. .
Frozen steam line? Wow, that's a new one on me. Is that steam pretty heavy when it freezes? <g>
Gentlemen, you not only need to worry about corroded pipe joints which don't make good electrical conductors but in todays plumbing there is a lot of plastic pipe used. One insulator (plastic pipe section) in your circuit and the weld current back feeds through the best path it can find usually the electrical panel ground.
unless you know for a fact that the pipe between the electrode and ground cables is a continous run of copper or steel pipe don't even think about it.
11-25-2005, 09:53 AM
when I did pipe thawing I would always remove the water meter and any grounds on the pipe going out. and connect my leads to the pipe going out and the closest fire hydrant In this way you elimenate any ground problems within the house you are working on, but maby not a neighbours house.I never did thawing inside the house with a welder. Almost every call for pipe thawing, the problem was in the street, driveway or sidewalk were snow cover was removed.If anyone knows a better way or a safer way please advise as this was a easy way to make money just hook the leads and wait for the water. A question to anyone who might know the answer. I presently have a 250 amp welder when I use it to thaw pipe the volts drop to less then 5 and amps go up a little over 300. If I were to use two thawing machines pluged into the same welder 115v plugs I can get 600 amps by ganging them. WHY
11-25-2005, 10:39 PM
jimmy dee wrote he got a call at a city building where they had cooked either the neutral or ground. he replaced the whole 100 amp panel? thawing pipes
02-15-2008, 04:10 PM
I have a need to prevent freezing if possible, rather than attempt to melt ice quickly. Is it practical to have a transformer supply just enough current to keep pipes warm enough to prevent icing up on a forecast cold night?
I have a short section of 1/2 copper pipe feeding the second floor master bath sink that freezes in zero weather. It is only about a 1 1/2 foot run in an insulated wall, facing the oncoming cold winds. This is a branch from inside the second floor servicing two bathrooms, and a whirlpool.
(Is the insulation packed down? Not yet checked out, have to cut into the wall first, then I might use a heat tape)
I propose to warm the pipes with a low-voltage transformer system (not a necessarily welder as such) , from inside the bath room. There are copper ground shunts installed on the adjacent Pearl Whirlpool water pipes and the pump, and also in the basement at the shutoff valves. I assume there are also copper shunts on the adjacent 2nd bath shower from which this master sink supply is drawn. I could also add shunts at the double sink connections in the other bath, if necessary. This should keep the majority of the current heating the short section of pipe, as far as the shunts, at least. Opinion?
The faucets are all fed with plastic, and a connection in cold weather is simple. I believe that if my transformer has no leakage, there should no stray currents outside this loop of hot and cold pipe, as I am not connecting my transformer secondary to ground.
I have a variable transformer to feed the minimum current into the pipes, an ammeter to monitor primary or secondary currents (have the necessary meter shunts for the high current side, can read up to 100 amps)
So far I have two 12V 10A transformers in parallel, and a 4KVA 120V/39V autotransformer to reduce the voltage further to about 4 volts, hopefully 60 A, but will I need to have more current??
How much current is needed to warm up a 1/2 inch copper pipe in an insulated wall?
02-15-2008, 04:31 PM
Not to short circuit the idea, but if this is just a stop gap until you can get a hole cut in the wall to keep the pipe from freezing, why not just let the water trickle out of the offending faucet for now. I worked at a commercial place where a long water pipe run in a crawl space would freeze when it got well below zero. We'd just turn on a faucet in the room farthest away. Just that little trickle of water would keep the pipe from freezing and it really didn't affect the water bill much. Would be much easier than fooling around with transformers heating those pipes until you get into the wall. Just a thought. Jim Don
PS Let us know what you do and how it works out.
02-15-2008, 05:06 PM
I'll second JimDon's suggestion. That's what most folks do if they suspect that the temps will get low enough to cause freezing. Just crack a faucet downstream of the questionable area.
02-15-2008, 10:39 PM
At my grandma's house they would let the kitchen faucet trickle a little when we had a cold blast because the pipes went up the outside wall.When I was a kid and would use the sink everyone would yell don't turn the water off!The good old days.:D It Works
02-17-2008, 02:19 AM
Leonard, there is such thing as a pipe heating cable. You can buy one in some hardware stores. Take a look at this, for example: http://www.amazon.com/Building-Products-Heating-Thermostat-04309/dp/B0006VAMRE/ref=sr_1_1?ie=UTF8&s=hi&qid=1203232580&sr=1-1
02-21-2008, 08:47 AM
That pipe heat cable does amazing things. We use them in four or five different spots around the water troughs on the farm. Just don't forget to plug them in when winter first comes!