No Penetration

[hotwine22]

Long tale, so please bear with me. I'm fairly new to MIG welding and really need some advice. I recently purchased a Lincoln SP-135T. Initially, I started practicing using 0.035" flux core wire as I didn't have a local source for shielding gas. Practiced on 0.060" plate and after a few hours was able to lay down a pretty consistent bead with nice prenetration. The welding was accompanied with that nice "frying bacon" sound. Starting to get a reasonable bead on joints, butt welds etc. but no one would confuse me with a professional... Moved over to thinner sheet metal (0.030") and the results are a lot spottier, with a lot of burn-through. All this practice is to get ready to make a lot - and I mean a LOT - of sheet metal repairs on my car restoration project (mostly 0.030 - 0.040 sheet metal). Last week I found a gas supplier made the switch to gas shielded welding using 0.023" L-56 wire from Lincoln. Thought the thinner wire would be better for the car body sheet metal. I set the gas flow to the tip at 25 SCFH per Linoln's recomendation. And reversed the polarity on the machine (positive ground). Practicing on 0.060" plate, the results have been HORRIBLE. Rather than getting that nice "frying bacon" sound, all I get is popping and splattering. Using the the recommended amp and wire speed settings on the Lincoln machine didn't work at all. I've tried all four amp setting on the machine and run the wire speed from 2 to 7. Nothing but splattering, and inconsistent puddling. The ONE consistent thing is absolutely no penetration. I can move the gun slowly over a very small area and build up a fair amount of weld metal, l let it cool and break it off with a pair of pliers. HELP!!! I'd like to stay with gas shielded welding as most of the work will be with thin car body sheet metal. Any help would be greatly appreciated. If any of you live in SW Louisiana, and can stop by the house for a lesson or two, I'll take you out for some boiled crawfish in return....
Many Thanks!!!
Steve
P.S. AWESOME SITE

 

[shenion]

You did change the rollers to the 0.023/0.6mm groove and change to a 0.025 tip?

0.023 is a lot less current than 0.035 gasless. Should be able to do 0.060 easily. I have found it is more sensitive to the distance from the torch to the work.

Oh, and welcome to the forums

 

[R Kraft]

Try reversing polarity.
Robert

 

[hotwine22]

Scott, Robert -
Thanks for quick response and suggestions. I did reverse the roller to the smaller groove and change the tip. Also tried changing the polarity. Didn't seem to make any noticable difference. One of the challenges in being new to welding is trying to describe the weld quality in words. But the one common occurance is no penetration into the materials being welded - the melted material just seems to build up on the surface. I'll try with some thinner metal (0.30") after lunch and report back.
Steve

 

[Sparkey]

Hi and welcome Steve!
Why don't you show us some pictures from your welds? would be much easier, and we just looove piccies on here!!

 

[hotwine22]

I'm not very good with a camera but will try to post a few pictures to give an idea of the problem I'm having.
Thanks,
Steve