My Hobart 140 will not get hot enough to make a weld. It will feed out the wire, make a spark, and the flux core wire will melt on top of the thin rouaght iron square tube fence but it will not melt into the tube/metial...sometimes the weld will hold, but most the time it breaks off as if it was welding on cast iron...any suggestions?

If you are using solid wire, you need to use a shielding gas like Carbon Dioxide or Argon. Otherwise you will not get *********** and the wire will leave random blobs.

If you are using flux cored wire, you do not need the shield gas as the core is producing the gas shield.

This should remedy it.

Your Linner of the gun could have a kink in it.

I have found that keeping the gun lead as straight as possible fixes this problem. Also it is sometimes recommended to use one tip size bigger when welding with flux core wire. My last spool was radnor flux core wire .030, and a .035 tip keeping the lead as straight as possible and it welded extremely well. If that doesn't solve it you should take everything apart and clean it / blow it out with compressed air.

First there is a overload for the drive motor incase the welding wire gets jammed. I've had one of these for a number of years and only recently understood the markings on the drive wheels. When the wheel is installed, the markings for the wire size is for the wire you're using. In other words, the marking is towards you but is indicating the size for the rear groove. For years, I looked at the numbers and assumed that they were for the groove closest to the numbers. I had no problem with solid wire, but with flux core all kinds of trouble. So, make sure you have the right groove for the wire size. Second make sure there are no kinks in your hose. Make sure your contact tips in the gun are the right size for your wire and in good condition A person has e a tendacy to make ther drive wheels tighter when the feed slips, this can cause problems for the flux core wire if the correct drive wheel is not selected.

Check your input line voltage. 115 volt Mig welders / plasma cutters need stable voltage / current. Test to see if the voltage drops to below 100 volts when welding. If so, find a more stable power supply.

check bridge rectifier ,sounds like it went bad.

If it is new i would not play around with the welder Just take it back to where you bought it get them to replace it under warranty

make sure rollers are clean and slots not wore out check alignment
do not over tighten wire feed so it smashes the wire
flux wire is hard to get a good setting
make sure if you can set it for gas welding it is not on this setting

A schematic would certainly help, give Hobart a call and ask for a wiring diagram. or manual. Hobart are very helpful and may even give you guidance, you may have to pay the postage, they usually fax these documents so it will not cost you anything.

If you are using flux wire and not shielding gas, your clamp should be positive and the wire should be negative. Heat is provided by the electrical arc that happens between the wire and the material. Your welder by itself does not pre heat the material and with 3/16 material you should not need to preheat anyway.

The electrical arc is kept consistent by adjusting the wire feed rate and the current applied. You will need to experiment with these settings to find what works best with your welder. For this welder and 3/16 material, I would suggest you start at the upper end of the current scale and about a third of the way up on wire speed. The welder might have a chart for these settings in the manual or inside cover.

If the wire feeds too fast, it will push the probe around and you will feel pressure as the wire feeds out. If the speed is too slow you will get large spatters and intermittent arcs. When properly adjusted the arc will sound even and consistent. The arc gap should always be about 1/8 of an inch.

To maintain enough heat for good penatration, do not move the probe too fast, work in a pattern and watch the weld pool (melted metal) and not the arc. Watching the weld pool will clue you in if you are moving too fast or too slow.

I hope this helps.

-Scott