What wire size are you using in your mig welder to butt weld? I have .030 but should I be using a smaller wire size? I am getting ready to weld in a trunk pan.

I've used .030 and .023 to butt weld panels but prefer .023.

.023 and 95/5 mix gas!!! We run to welders in my shop, one Miller 251 setup with .30 and 75/25 mix for structural work, and a Lincoln 175 with .023 and 95/5 for sheetmetal only. Its amazing how much more penetration at a lower heat setting you get with the 95/5 mix gas!!

Thanks for the help. I have been using .030 with 75/25 mix in my Miller 135 for some structural work on the frame. This setup just seems a little heavy for the thin sheet metal work. I will try the .023 wire. My one and only 75/25 tank is full, do you think it is worth switching to 95/5 gas? I need to do both structural and sheet metal work with this one machine.

I am getting ready to weld in a trunk pan.

Dar:

Here is a past post discussing a wire specifically for sheet metal MIG welding - http://www.camaros.net/forums/showthread.php?t=5744&highlight=twenty+gauge+wire

Several members on the board, myself included, have been using this wire with excellent results for sheet metal work for several years.
I have personnally found this .030" wire gives me much better seams and does not leave a big ridge to be ground off later, which can lead to thin heat-warped areas on the repair after grinding.
Note that this wire is .030" v.s. the .023" wire I previously used for sheet metal repairs. But, the center is a hollow core filled with a powdered-metal-flux type material that gives this wire it's excellent weld properties.
This IS NOT 'flux-core' wire! You still need shielding gas to use it.
Here is link to the J.W. Harris site for the tech sheet - http://www.jwharris.com/images/twentygauge.pdf

I also have used this on a Miller 135 and it performs great on that welder.
Use initial settings like you would for a standard .023" wire for your trial welds and then adjust as needed.
Stay with the 25/75 mix - it performs best for most applications.

Hope this helps;
John

I find that 023 wire causes taller welds and more grinding than 030. Both will do the job if you set voltage and wire speed correctly.

John: Thanks!! I had not heard of this wire. Funny, my neighbor on one side works for a welding supplier (yes, I get free promotional stuff from time to time) and my neighbor on the other side is a professional welder. Neither of them told me about this wire. I will definately give it a try. What settings do you use on your Miller 135? The Harris info suggests 2.5 volts and 32 feed for 20 ga metal. Is that about right?

Sounds very interesting John. I'll look into getting some to try. Thanks!

.03 wire with gas

Daral, the setting table for "twenty gauge" and the setting on the welder chart for wire vs material thickness are only starting points. You need to tune up the settings to suit your welding speed, line voltage, the metal thickness, variations in the welder, push vs pull welding etc. Start with those settings but tweak the dials for best results. Try out a scrap first to get tuned up. You can compare your weld against those in the photo, figure 17 at:

http://www.millerwelds.com/education/tech_tips/MIG_tips/

That picture will help you get tuned up. Don't be afraid to deviate from the table numbers to get results from your welder. On my Miller 175, I think I used the 2.0/24 on twenty gauge. The twenty gauge uses settings similar to .023 wire even though it's .030 thick. I didn't like the smoke that twenty gauge puts off and ended up putting E6 .03 wire back in. With the welder correctly adjusted both wires did equivalently.

Tired68: Thanks for the tips. I am new to welding but my neighbor is a professional welder with over 20 years of experience. He has been a great help with tuning up my Miller. But he works on thick plate steel so he had me running pretty hot.

I am going to try the twenty gauge, but they do warn about the smoke being a health hazard. I have very good ventillation in my shop so it should not be a problem. I am a firm believer in practicing. I have gotten pretty good using the .030 wire on my frame. The trunk sheet metal is next. Thanks to everyone for your help and suggestions.

Sorry I was late getting back to this, doing a kitchen remodel and the countertop guys finally showed (didn't do much work, just showed up :rolleyes: man, I wish I knew how to do Granite myself...).
Like 'tired' said - you can try the intial settings on the "TwentyGauge" box to set your welder if you want and then do some trial welds. I usually end up with a slightly lower heat and slightly higher feed range on older metal and the opposite for all newer - really depends on how thick the piece(s) are also.
The smoke (fumes) have never been an issue with me. MIG welding does produce more smoke than TIG and this wire may give off more smoke (any of it is bad as it contains gasious metals and compounds) but, I also weld in very well ventilated areas (you could read 'outdoors' here normally if you want ;) ) so it's never been an issue - heck, I think there's that same warning on a can of spray wipped-cream in my frig... :D

I'm just a big fan of the bead produced by the "twenty-g" stuff - it's so easy to knock down as I finish the panels. Not that hard-as-nails bead I always got with .023.
Price is in line with any good wire and the gas is the same as I would use if I need to switch out the wire to another size for other work - just switch wire and go...
Just has become my wire of choice for panel work.

Thanks Vintage 68. I picked up some "Twenty Gauge" yesterday and plan to practice with it this weekend.

I watched as they cut and polished a marble slab for my kitchen counter top. Wow, that is some hard stuff and granite is even harder. I think I will stick with metal work. Thanks again.

Ive been welding for over 30 years and I have found that 95/5 is a better gas than the 75/25 mix. It does produce better penetration with lower settings on the welder making a smooth weld. Even if you are welding structural parts, like the frame, 95/5 is still better. It welds much cleaner than 75/25 because you can adjust the arc to basically spray the metal and cause very little to no weld spatter. I personally dont like 75/25 unless using it with fluxcore. Yes, even though it has flux in the core, the weld is still much better with gas. Kevin

Update: I tried the Twenty Gauge cored wire this weekend with a 75/25 mix. I am a welding rookie but found it much easier to get a nice clean bead with this wire compared to the solid .030 I was using. I played with the voltage and wire speed until I was happy with the bead and penetration. In the end I was using a voltage setting on my Miller 135 at just under 2, which is lower than the setting I was using with the solid .030 wire.

Vintage 68 was right, it was much easier to knock down the bead from the Twenty Gauge compared to solid .030.

Thanks to everyone for your suggestions. After a little more practice, I start welding in the shock towers and trunk pan next weekend.