Welders!

[Opper77]

I think the popular misconception is that because aluminum has a lower melting temperature it "welds" at a lower temp also (read as aperage). The reality is that aluminum takes much more current to weld than the same thickness steel. Most 135 amp welders will JUST be able to weld aluminum properly with .035" wire on a maximum thickness of 1/8" material. If you must weld alum. with a smaller machine, my suggestion would be to use the smallest diameter wire possible and get a helium/argon mix (at least 80% helium) as it helps to input more heat into the material than just a straight argon shielding gas.

I used to TIG weld 600lb. aluminum castings at around 400A day in and day out; and even at that amperage, if I used a stright argon (as sometimes happened when we ran out of the proper helium mix) I could barely get a puddle started.

It all goes back to the high heat conductance of aluminum. If you take a 2 foot long rod and put heat to one end, the other end will get hot too. This is much different than steel of course (stainless steel in particular has a very low heat conductance, and takes LESS amperage that mild steel to weld)

One other nugget: The wire speed on a MIG welder is actually your AMPERAGE control. The thicker the material, the more amperage you need to properly fuse it; and thus the faster wire speed required. Of course your voltage must be set properly to help "wet" the puddle and "push" the weld puddle properly.

[chickenwing]

I do not think you would have a problem welding aluminum if you stay thin either. Have not migged any Al yet but have been watching another class that is. Have been tigging some 1/8 inch Al. Takes a bit to start the puddle but the further ya go you either gotta lift up on the pedal or speed the heck up. Tig is neat but gotta say I'd rather use the Mig. It's much faster and does not take anywhere near the practice required for the Tig.

Tips I have: Clean your work with a dedicated stainless steel brush (do not want to contaminate the work) and try to weld as soon as you can, the oxide layer starts to reform immediately. The oxide layer has a higher melting temp than the Al. Make sure you get a dedicated liner for Al (don;t want to contaminate the wire). If you can, cut the feed hose length down. Keep the hose straight too. These 2 items will help eliminate birds nest with less friction on the line. Saw this kit another member posted (forget who so can't credit) http://www.wirepropellant.com/company.php looks pretty neat but think ya can get by ok without it. Far as gas, see above post.

On another note, I found a site with info from a guy by Kent White. http://metalshapers.org/tips/white/a...ding/index.htm He goes on and on about oxy-welding Al. I figure if they were oxi-welding Al on fighters in WWII, that is good enough for a low life like me. Reading all of this info got me to wondering.... what if I use the oxy-weld flux but use a wirefeed instead of a torch? Things that make you go hmm... The hard core guys now are wondering what's the benefit? Money! I only have a mig. I was doin good to get the welder and I lucked out gettin the tank for free. Another dedicated argon/helum tank or an oxy-acetlyne set-up is just too soon to justify to the Mrs.! If I ever get around too it, I'll let y'all know how it turns out.

[Opper77]

The above about the stainless brush is a good point. Aluminum has whats called a "refractory" oxide and as stated has a much higher melting point than the base aluminum....this is why when you get aluminum hot enough to melt it appears to have a "skin" over the molten pool.

When you TIG weld alum. you must use AC High Freq. current to break up this oxide and penetrate properly. No amount of cleaning with ANYTHING will get rid of it; as it forms as soon as oxygen touches the material. Any MIG welder capable running alum. will either have an extra external box or internal circuit that is basically just a transformer (regular MIG is AC rectified to DC) that enables breakdown of the oxide layer.

Also, one thing to note is that solid steel wire uses smooth grooved drive rollers while tubular (fluxcore) and aluminum use knurled groove drive rolls and if you're going to run alot of wire, proper alum. setups use a "pull feed" gun in place of the "push feed" to avoid feeding problems.

I have used aluminum stick rods in a pinch, but IMHO they are crap once you're used to making art with a good TIG setup. My grandfather is a big fan of the oxy/acetylene setup on aluminum and has done some decent work with it on light gauge sheeting on his '62 Mac.

[VetteVet]

I've got a miller challenger and I have been real happy with it until just recently. I was trying to weld some 1/8th inch brackets and noticed that the wire was coming out fast and building high instead of a nice bead. I'm using the flux core and have had good results with it although I know I can get a better weld with the gas. Anyway I tried to adjust the wire speed and it won't slow much even on the lowest setting. It used to barely creep at that setting. I know it's probably the speed control but I haven't opened it up yet.
I think the heat setting raises the wire speed a little if you are on the higher settings so I turned the heat down to the lowest setting and the wire still flew out of the nozzle. I was wondering if anyone has had this happen and is there something to replace or do I need a new speed control?

[Opper77]

Is the dial just spinning on the rheostat underneath? Maybe the knob is loose and its making you think you adjusted it but really nothing happened.....

seen it happen more than once

[VetteVet]

I will check it out when I open the case. It stops at just below zero and on the high end where it should but it may be slipping on the inside like you say. I know it's a variable resister that controls the motor so it may be something simple like that. The machine is like new and I haven't used it that much so I was surprised to see it mess up. I will look at it and let you know what I find.
Thanks for the tip.

[Opper77]

I just downloaded the owner's manual to see the unit itself....a couple other things to try

1) make sure the rheostat isn't grounding out to the chassis through dirt, dust etc

2) throw a multimeter set on ohms on the leads to the switch and rotate it. you should see a varying number as you turn it... if not, it may be grounded out somewhere inside

3) just double check the voltage range selector and make sure its firmly seated into a setting. weird things can happen when its JUST out and its arcing to 2 settings (had an old Hobart that had this problem chronically)


Hope all this helps

[chickenwing]

Originally Posted by Opper77

...Any MIG welder capable running alum. will either have an extra external box or internal circuit that is basically just a transformer (regular MIG is AC rectified to DC) that enables breakdown of the oxide layer....

Mac.

A lil more on this box? I was day-dreaming before about Millers spoolmate #3035. For my welder (millermatic 175), it does indeed need an extra box. I thought the box was just for gas control as my welder does not have an extra gas connection. I did not think the box added high frequency. I thought high frequency was used just for starting/maintaining the arc in tig.

Edit: Oh, I liked your "making art" comment. One day maybe I too can make art.

[Opper77]

Like I said before; it need the box to adapt low current ac to high current ac, where normal MIG uses a rectifier to turn low current ac to high current DC...

all in the circuits my friend

[VetteVet]

Originally Posted by Opper77

I just downloaded the owner's manual to see the unit itself....a couple other things to try

1) make sure the rheostat isn't grounding out to the chassis through dirt, dust etc

2) throw a multimeter set on ohms on the leads to the switch and rotate it. you should see a varying number as you turn it... if not, it may be grounded out somewhere inside

3) just double check the voltage range selector and make sure its firmly seated into a setting. weird things can happen when its JUST out and its arcing to 2 settings (had an old Hobart that had this problem chronically)


Hope all this helps

1. no grounds to chassis
2 Ohmeter read between 3 ohms on high to 15 on lowest setting as I cycled the knob. At first it read three ohms all the time but as I worked it back and forth it started reading between 3 and 15. I plugged it in and tried it and it slowed down a lot with low voltage but still seems faster than it did when new. The voltage setting affects the speed too so maybe I can get more information from the manual if I can find it when I have more time.
3. The inside of the machine is very clean and the voltage setting was always on the mark. It may just need to be used more. LOL
thanks for the help.

[jay-dawg]

Hi guys,

Is the Lincolon Weld Pak a decent 110v welder? I have a chance to buy a used one for $175 although I'll offer $150. I'm not looking to weld anything to the frame. Just weld in patch panels and fill holes on my 68. Here's the link:

http://www.homedepot.com/prel80/HDUS...=10-14445721-2

Maybe I should wait and get the mig welder:

http://www.homedepot.com/prel80/HDUS...=10-14445721-2

What do you guys think?

Thanks in advance,
Jay

[gferris5]

It may not be worth it. The Weld-Pak would be a bear to try and weld sheet metal since it is flux core only--splatter city, and if it does convert to MIG (I don't think it does) it will require a conversion kit. I'm no expert however, just my .02. The guy at the welding store today described them as "Worthless Toys," but he has an agenda.
Cheers!

[tedbick]

what is better c02 or argon mix ?helium?

[rodnok1]

Most applications you can use argon mix, it's cheaper too. Pure argon is used for TIG and aluminum if I'm not mistaken.

[tcoop68]

Originally Posted by c10chevy69

I am looking at buying a welder for sheetmetal and lightweight fabrication. My problem is that I do not have a garage to weld in. Does anyone have any suggestions in this situation. All of the bodywork will have to be done outside in the wind.

Say,if you get a small mig you can weld with a fluxcore wire that has the flux inside and it takes no gas and you can use it in the wind.But the best welds will be a welder with gas.I have 3 lincoln welders myself but at work we have a little 110volt hobart all you have to do is reverse the leads to use fluxcore wire.