Using An Arc Welder To Thaw Frozen Water Pipes
While arc welders are not specifically designed for thawing frozen water pipes, they have been used for this purpose.The reason for this is that arc welders are a good source of low voltage,high current electric power which when flowing through the pipe,causes it to heat and melt the frozen water. Properly used,welders are a fast low cost method of thawing pipes without digging or the need of an open flame.When pipes are accessible however,they can be thawed more safely,easily and quickly by careful use of a small electric heater or heat lamp. Because of the potential dangers in thawing pipes with high electric current,it is of the utmost importance that it be done only by qualified people after reviewing the following information.
Warning: The use of electric current to thaw pipes if not done properly can result in fire,explosion,damage to wiring which may make it unsafe,damage to pipes,burning up the welder, or other hazards not to mention loss of life or severe burn and electrical shock resulting death or maybe even dismemberment. The following will give you some appropiate methods and safeguards.However ,resonsibility for the application of this information and using good judgement in the use of a welder to thaw pipes is yours Davis Plumbing is not responsible for what you do with this information.
How It Works
When electrical current passes through a metal pipe,the pipes electrical resistance causes heat to be generated which thaws the frozen water. Here are the factors which affect the time and amperage required for thawing to be effective.
Piping Material
Warning: Thawing cannot be accomplished on non-conductive pipe,such as plastic,or on metallic pipe with non conductive joints in the section to be thawed
Copper and steel are typically used for most water pipe. Steel pipe has a higher electrical resistance and heats more rapidly than copper when a given amount of electric current passes through it.
Size Of Pipe
A small diameter pipe has a higher electrical resistance because of its smaller cross sectional area and will therefore heat more rapidly than a large diameter pipe when a given amount of electrical current is passed through it. Thus,it takes higher current and longer times to thaw large diameter pipes. The time and current required for thawing are about the same for any length of pipe,except that as the length increases,the voltage drop increases,which in turn causes a reduction in current. It is best to apply the current across the shortest area of pipe in which the freezing has occured.
Current (amperage)
The amount of heat in the pipe is most dependent upon the amount of electric current available. The greater the current passed through a pipe, the greater the heat generated. With twice as many amperes, the heating rate is four times is fast. If the number of amperes is increased three times,the heating rate is nine times as fast.
Time Required
the time required for thawing different sizes of steel pipe is given in the table below. Copper pipe requires more current than steel pipe for the same thawing time. to thaw 1/2 copper pipe, increase the figures for steel by 10%. Increase the current for steel pipe by 25% to thaw 3/4 copper pipe. Larger copper pipes will require an even larger increase of current. Of course the lower the temperature the longer it will take to thaw the pipe.
Required Equipment
Most constant current,industrial AC and DC welders and most air cooled engine driven welders can be use for thawing pipe. Smaller capacity welders, if suitable for pipe thawing,sometimes have a specific selector switch setting for thawing.
Warning: Under no circumstances should any pipe thawing activity take place without a knowledgable professional in attendance during the entire time.Pay particular attention to the warning below. If you do not follow proper procedures you can ruin your equipment ,your house ,possibly your neighbors house and kill or maim yourself,cause an explosion or get electrocuted and severely damage property and your piping as well.
Isolate The frozen Section
This can be done by turning various faucets on until the specific frozen areas are determined.
Confine your Activity
Do Not attempt to thaw pipes by making connections to neighboring houses. Stay away from fire hydrants and disconnect your water meter.
Check Your Connections
The frozen section of pipe must complete the electrical circuit from the welder. Always be certain that there are no insulated joints or plastic pipe sections that could prevent the electric current from passing throught he frozen section of pipe. Such interruptions will cause the current to flow through alternate paths if they complete the circuit. Thes alternate paths could take the form of gas pipes, neutral conductors or grounding wires of the electrical system which may not have sufficient electrical capacity, causing them to burn open (and therefore not be able to perform their intended function in the future) or become so hot as to cause a fire hazard or explosion. Further, even if the frozen section does not complete the electrical circuit these same types of alternate paths may still be in electrical parallel and draw current from the welder. Under these conditions they will need to be temporarily disconnected during the pipe thawing operation.
For example, the sketches below show various connections. In a situation shown below, if the barn has electric power you must chech to make sure there is not awire connected to the pipe you are thawing. In the other drawing you need to check to make sure the dishwasher or disposal is not going to create a parallel path. These connections are very important and must be disconnected or you will be sorry.
Work Close
Both of your cable connections should be as close as possible to the frozen area. A small empty pipe in the circuit could get hot before a larger frozen pipe thaws. This could easily melt the solder in the copper lines,causing water damage, or the empty pipe may become so hot it starts a fire against a floor joist or other building materials or objects in the area.
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Welder Thawing
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