Hobart porta stick .is it possible to do steel and aluminum with this machine.dc only ?

Not sure what machine you have, but it should be DC straight (electrode negative or DCEN) and DC reverse (electrode positive or DCEP). The polarities have different characteristics. For example, if you're planning to TIG weld, you would either use DCEN or AC (if welding aluminum). For the general stick welding process, DCEP tends to give you a deeper weld. The welding rod you buy will have recommended machine polarity and amperage range settings, you should use the recommended polarity for whichever rod you're using because different rods are designed to weld under different circumstances. But, generally speaking, most welding rods for steel will work on DCEP without much trouble.

It's call gun block assy. part number is: HOB 193189, DUAL 035-045 drive roll part number is: HOB 202926

DC current, electrode negative (DC Straight, DC-), High frequency for start only (really don't have to use high freq at all for steel but it helps establish the arc without scratching), 1 amp per thousandth of material thickness is a good setting to start, adjust from there for the job. 1 amp/thousandth also applies to aluminum- it has a lower melting point than steel but conducts heat much better so power to weld is very nearly the same.

Use a sharp tungsten, don't ball it at all (as you would for AC work).

lp

Rated Output at 20% Duty Cycle 150 A at 16 VAC
150 A at 16 VDC Welding Amperage Ranges AC/DC 10 - 165A Max. Open-Circuit Voltage 80 V Amps Input at Rated Output AC-230V: 21A
DC-230V: 23A You need to configure the machine to specifications of the material you going to weld.That is :
-The material of the job
-And the proper amperage to use for the material.
-For aluminum you will use A/C
-Stainless Steele / Chrome Molly D/C

Aluminum MIG Welding
1. The best feeding of wire for aluminum is done with a spool gun. If you can't use a spool gun, use the shortest gun possible and keep the gun as straight as possible. Use Argon only for shielding gas. Only use a push gun technique when welding aluminum. 2. If you are having feeding problems, one thing you can try is a contact tip that is one size bigger than your wire. 3. The most common wire type is ER4043 for all-purpose work. ER5356 is a stiffer wire (easier to feed), and is used when more rigid, higher-strength weld properties are needed. 4. Clean the aluminum before welding, to remove the oxide layer. Use a stainless steel wire brush used only for cleaning aluminum. 5. Fill the crater at the end of the weld to avoid a crack. One way to do this is to dwell in the weld pool for a second at the end of the weld.

your hobart machine it's not suit up for standard aluminum welding, the lenght of the gun it's too long therefore the wire will nest at the drive rolls. You need to buy a spool gun. Or change gun liner for a teflon one (instead of metal one), then change the drive roll for knurled ones and finally oversize your tip if you can. No need to do ALL this if you buy a spool gun.

Aluminum key is soft enough to shear but not damage the slot on crank shaft or flywheel.

steel pan and it magnet is in the inside of pan

first the handler 120 is 110volt,the handler 220 is 220 volt.the rubber wheel is for welding aluminum.

Usually a flux core only welds steel. It is a higher penetration weld than a MIG. Usually it acts similar to 6011 rods in SMA (Shielded Metal Arc) welding -- a.k.a. stick welding -- if you're familiar with that. I don't believe there is such a thing as flux wire for aluminum. There may be stainless wire for it, but I've never seen it. It probably could also be used for building up cast iron and cast steel, but nothing structural. I have a Chicago Electric one and I love it -- simple and it penetrates hard. My 90 amp will weld to 3/8" without breaking a sweat and if I baby it will go to 1/2" or better. It is difficult to go much lower than 12 or 14 gauge though due to the high penetration.