I have a stainless 6" x 10" x 40" parkerizing tank that I needed a heat source for to finish some rifle parts. Parkerizing is a fairly simple process that doesn't require a lot of preparation but does need some basic components. Midway and Brownel both sell the solution in gallon size jugs. You mix this with four gallons of distilled water. You really need to use distilled water because chlorine, minerals, or even flouride will screw up the finish. You need to heat this solution to 175-190 degrees and maintain this temperature through-out the process. You also need to drop a steel-wool pad into the new solution at temperature for 30 minutes initially to get the solution prepared. Steel preparation consists of blasting the metal; if there are any remnants of the old bluing, it will make ugly black spots. the parts have to be cleaned and degreased. I use brake cleaner to remove the oil and grease then put the pieces through the dishwasher with ordinary dish-washing soap. I use stainless wire to hold the pieces being treated in the solution. After the part reaches the shade that you desire, put it under the garden hose to rinse it off and brush it with oil to completely arrest the process, otherwise, the part might continue to cook and ruin the finish. The heater I made by taking a length of 1/2 black iron pipe and drilling 3/32" holes the length on 3/4" centers. One end is capped and the other end is reduced to 1/8" pipe thread (brass bushing with 90 degree elbow) to connect the regulated propane source. Use a welding type regulator, the grill type will work but it is very slow and if the wind is blowing, the flame will run up and down the pipe. I used a pair of bricks with holes to insert the burner and hold the tank on top. This worked out very well and made a stable platform to work from.