17.When the tank is finished it is always a good idea to pressure test. I use a small paintgun regulator (not a restrictor valve) and a short length of 3/8-inch air line. I have found that simply forcing this size hose inside a standard 22mm petcock bung is a simple airtight seal. Only a few pounds of pressure are needed.
17. When the tank is finished it is always a good idea to pressure test. I use a small pai
When welding, I try to keep the heat concentrated to get full penetration using minimum heat. I try to keep the tungsten as close as possible and the arc as short as possible without contaminating it in the weld puddle. I set the machine to around 50 amps and by modulating the foot control I am probably using approximately 30-35 amps during welding. When starting out TIG welding, people can have a tendency to hold the tungsten farther away to avoid touching it. This causes the arc/heat to spread out requiring more heat to get penetration.
18.All weld seams were confirmed to be leak free by submerging the pressurized tank in water.
18. All weld seams were confirmed to be leak free by submerging the pressurized tank in wa
Another thing to be conscious of is the way filler rod is added. I find the most efficient use of heat is to dip the rod directly into the molten weld puddle. If the rod is allowed to melt and drip off slightly ahead of the weld, more heat will be required to melt this in and get full penetration. I use approximately 8-10 inches of filler rod per 12 inches of weld. Using too little filler rod will leave an undercut weld that is thinner and weaker than the surrounding metal. If too much filler rod is used, and the excess is not ground off, small valleys will appear on either side of the weld after hammer and dollying and are difficult to sand out. After the weld cools, both sides are again wire-wheeled to remove oxides that can mark hammers, dollies, planishing dies, etc. The weld is planished by machine or hand hammer and dolly. If all steps have gone as planned, the resulting weld will have full penetration, any distortion will be relieved, and the weld bead will be even or barely above the metals surface.
I always recommend pressure-testing tanks when finished. I use a small paintgun regulator set low (probably 5 psi or so) to pressurize the tank and submerge in a tub of water. The last thing to consider is to be selective in who you have do the paint prep. It doesn’t take long for someone who is overly aggressive with a grinder to weaken a corner or other areas on a tank. Remember this is thin sheetmetal. It is strong but thin spots give it a reason to fail. Make sure the person is experienced with tanks not just automotive parts.
I hope some of this information is helpful for those of you starting out with sheetmetal projects. With practice and experience as you continue to weld you will find techniques and tricks that work best for you. HB
Weld, weld, weld
If you’re looking to do your own welding and need equipment, with some light research you’ll find welders come in all sorts of shapes, sizes, configurations, applications, prices, etc. Here are two welders from HTP that can get you started in the right direction to melting metal together in your own garage.
HTP MTS 160 Sale Price of $1,199
Just by looking at the side of this compact box, you notice right off the bat this little buzzer is feature packed. Capable of tackling many welding jobs and handling MIG, TIG, or Stick (hence the MTS moniker) welding, this 39-pound, 16-1/2-inch–long, 8-1/4-inch-wide, and 13-1/4-inch–tall machine is perfect for the confines of a garage workshop, and essentially gives you three welders in one. The advanced inverter power source will run on a 20-amp 220-volt single phase outlet, and the machine has a duty cycle of 40 percent at 160 amps. It welds both solid and flux-core wires in MIG mode, and can weld steel, stainless steel, and 4130 chrome moly tubing in the DC lift arc mode. Just about the only drawback is that it doesn’t TIG weld aluminum.
HTP Invertig 201 AC/DC Sale Price of $2,395
If you know you’re going to be doing a lot of TIG welding on thin aluminum, then the Invertig 201 might be just what you need. Slightly larger than the MTS but still rather compact, this machine measures in at 20 inches long, 9 1/2 inches wide, and 21 inches tall. With its advanced inverter technology, HTP is able to get 200 amps of welding power while only pulling 30 amps from the wall, making it very energy efficient. HTP states that compared to competitive transformer machines, the Invertig 201 produces 10 percent more welding current while using 60 percent less electricity. Inverter technology produces a smooth, stable arc, making intricate work on mild steel, chrome moly, and stainless steel a breeze. And with the variable frequency in AC, the machine produces excellent results when welding thin aluminum. When it comes to conventional arc welding, the lift arc mode in conjunction with the foot pedal makes it much easier to strike your arc without sticking the electrode.
Hardison Metal Shaping LLC
(503) 936-1079 | hardisonmetalshaping.com
HTP America, Inc.