Hi,

This is my first post. My name is Mike Cole.

I have done some research on propylene glycol antifreeze for water cooled TIG torches and water cooled MIG guns. I have found 3 alternatives to Binzel-Abicor's ABI-CoolECO coolant and Esab's Thermal Dynamics 7-35809 Extra Cool which only contain 30% propylene glycol antifreeze which will only give freeze protection down to +10 Fahrenheit. Not good for those of you who do not want to heat their garage or welding shop just to keep the TIG welder warm. These alternativees will be for making or buying a 50/50 solution with distilled water that has a freezing point of about -28 Fahrenheit. Propylene glycol is the antifreeze that is used as a food and drug additive and where you do not have to report spills to the authorities. What I have in my car engine is Prestone Lowtox propylene glycol antifreeze. This is because i do not want a leak to harm people's pets let alone what happens when I drain and flush the system once every 5 years.

You cannot use automotive propylene glycol antifreeze such as Prestone Lowtox or Peak Sierra. These contain silicates that are intended to plug small leaks and is detrimental to nonautomotive water pumps.

The most practical is Dowfrost HD which is available in 1 gallon jugs and 5 gallon pails from a number of sources. Amazon's prices are such that 3 1 gallon bottles are about the same price as a 5 gallon pail so you might as well buy the pail so you get 2 gallons free. You will have to use a turkey baster that is dedicated to the purpose and rinsed out with distilled water. This product contains a rust inhibitor and a fluorescent yellow dye which makes leaks easy to find.

One issue is how much electricity a 50/50 propylene glycol/ distilled water solution will conduct. An engineering document I found on Dow's website gave me the data to figure out electrical conductivity. To find the document Google Dowfrost and mho which is the unit of electrical conductivity and is the reciprocal of the Ohm. The electrical conductivity of a 50% by weight ( which is only 1/2% different by 50/50 volume ) Dowfrost HD and distilled water is 2.06E-3 ( 0.00206 ) mho per centimeter. Some material sheets used the more modern name of a mho which is Siemen.

Store bought distilled water is about 6 to 8 megohm-cm ( 6 to 8 million Ohms-cm ) which is find. Save the empty jugs after you use them to fill humidifiers, etc. I use it to make buffered salt water for washing my nose 3.5 quarts in what used to be a Hawaiian Punch bottle. Is 2 such containers each month.

If we take the reciprocal of this figure ( dived 1 by this figure ) we get 485.4 Ohm-cm. We then find the internal cross section of 3/8 inch inside diameter tubing which is a little bit bigger than 9 mm ID tubing. Multiply 0.375 inches by 2.54 cm per inch. Square that ( multiply it by itself ), divide by 4, then multiply by Pi ( 3.141592654 in my calculator ). This will be the cross section in square centimeters. Divide 4.854 Ohm-cm by the cross section which is 0.712557392 square centimeters. The result is 681.2600618 Ohms per centimeteresfor each of the 2 tubes. We then multiply by length in centimeters of your TIG or MIG torch. Divide by 2 to account of 2 tubes electrically in parallel.

For a TIG torch with 12.5 foot long hose and electrical conductor assembly we get 304.8 centimeters of length and an electrical resistance 207648.0668 Ohms. Divide an open circuit voltage of 70 volts by this number and you get 0.539 milliamperes ( 0.000539 Amperes ) of leakage current barely above the level of human perception and absorbable by the equipment ground of the cooler. ALWAYS do the rounding after completing all calculations.

For a water cooled MIG gun 10 feet long we get 0.385 milliamperes at 40 volts. ( Actually they usually operate at a lower voltage.

There are 2 alternatives. Old World Industries d.b.a. Peak has Thermal Charge 50/50 Prediluted Heat Transfer Fluid. It is also available as concentrate to mix with distilled water. It is only available in 55 gallon drums which is great if you are filling a fleet like over at Honda. One of the welding equipment compoanies told me about this.

Interstate Chemical Corporation has a high purity propylene glycol but it is clear and has no Corrosion inhibitors such as dipotassium phosphate like Dowfrost HD does.

Mike Cole

Columbus, Ohio

Ohio Electrical Contractor License No. EL45,008

Bachelor of Science Electrical Engineering and Physics John Carroll University.