Need Welding Tips...

[rennch]

Hi folks,

I got a welder last winter and have done a couple of rust repairs with it so far. I'm definitely digging being able to weld on the P-car...it opens up a whole new world!

I am not a welding master, however. Right now, I have a bit of a dilemma...my welder (which I got from harbor freight) has four different settings. At setting one, (the lower voltage) my welds are very proud, and require a lot of grinding. At setting two, they burn through. I'm hoping there's a way, either with technique, or gas setting, or whatever, I can get them to be flat and clean. tomorrow I'll grab the settings from the welder and post them.

I'm just curious what settings people are typically using for our PCar bodywork. I have to do my rockers pretty soon and I don't want to burn through all over the place.

Thanks!

[rennch]

This *might* be it...but I'll know when I head to the garage tomorrow:

* Welding current range: 58 to 110 amps
* Input: single phase 220 volts, 60 Hz
* Open voltage: 19 to 30
* Duty cycle: 60% @ 55 amps, 28% @ 80 amps, 15% @ 110 amps
* Draws 15.7 amps @ 220 volts
* Weldable wires: 0.023'' to 0.035'' steel and stainless steel, 0.030'' to 0.035'' aluminum, 0.030'' flux-cored

[Allenk]

There should be some articles to search for on this. What wire size are you using? Are you using flux core wire or using gas? You typically want to use small welds 1/2" to 3/4" and small wire with gas. As for your problem as described, you may want to try slowing the wire speed on the lower setting or speeding up the wire feed on the higher setting.

[greglepore]

I have the same welder, and the lack of temp adjustability compared to more expensive welders is one of the drawbacks.

I'd try it at min/2 and slow down the wire. You might want to try .023 wire as well, rather than slowing it too much.

BTW, I changed out the stock wire sleeve in the unit for bicycle cable housing, and it made a huge difference in avoiding wire jams and rats nests.

[Tim Hancock]

The problem with MIG welding thin materials in general, is that the material being welded heats up rapidily due to it's thin nature. If a welder is set up to penetrate right at the start of the weld, within seconds, the heat will build and you will start burning thru. If you set it up at a low heat setting, the first few seconds of weld will not penetrate until the heat builds up.

The best thing to do for the best penetration is to set it up so that you are only doing small, short stitch welds that are fully penetrated. IOW, pull the trigger, weld for 1/4- 1/2" then stop and move to another area that has cooled down.

Finer control might help, but everyone who MIG welds thin materials will experience the same problems to some degree. Sometimes one can hold a piece of copper against the back side of the joint to act as a heat sink, which will help prevent burn thru, but jumping around with short stitches is the most often used method when MIG welding thin materials. Some advanced welders have programable current features that allow the current to start high then ramp down as the weld progresses and heat builds, but to help avoid warpage in thin panels, it is best to skip around anyways.

[Rot 911]

Like the others said, use .023 wire on sheet metal.

[na2ub]

I was having a horrible burn through problem, and JW recommended spot welding, rather than seam welding, and then weld in between the spots and so on until the whole seam is welded. What great advice, it really helped.

Doug

[awis321]

In the same boat. Here's a website I came across that has some good info http://www.metalmeet.com

- Dennis

[rennch]

Hi guys,

Good advice, all. I especially liked the bike cable housing idea...the wire feed on this welder was a real pain in the a$$ by binding, but I seem to have sorted it out now. I did replace the stock wire with some thinner stuff, so I'll need to check what it is and see what I'm welding.

The *slowing down* the wire at the lower amperage seems counterintuitive to me, for I would think I would want *more* metal there, not less. But I'll trust you guys, since you're obviously more experienced than I am.

I'll check out that metalmeet.com site as well. Thanks so much for the tips guys.

[dougcl]

Maybe it makes more intuitive sense if you consider that the more wire coming out the tip, the more buildup you will have at the weld. Turn the speed down, less buildup. Turn the wire speed up, more buildup.

Doug

[rennch]

Yea, I just spent a few minutes on the Metal Meet site...great resource! Has anyone made a copper "backer" that they can weld on to prevent burnthrough? What did you use?

The "slowing the wire down" concept is definitely making more sense to me now that I'm wrapping my head around it.

I'm still contemplating whether I'm going to weld or glue my flares on...there seem to be good positives for each one.

[Brad01mc]

Hi!

I would definitely suggest that you contact your local adult/community education program and see if there is a welding course that you can take. I ended up taking a high school night class and its absolutely worth every minute and dollar spent.

I own a miller MIG, but took the arc welding / basics, because I was interested in learning more about the basic foundation skills. If you can "master" arc welding, MIG is a piece of cake!

If I were to do things over, I would buy a TIG.

Anyway, welding is an art as well as a science, so I would strongly suggest that you go take a course. You'll learn about amps, volts, heat, technique, etc... all the stuff to make you proficient. Not only that, but I probably burned through the price of the course in materials alone!!

It's time well spent and you'll be a better welder in the long run.

Sorry if this comes across as a rant.

Brad

[rennch]

Well, I have two rockers, a gas tank support, and flares to weld on, in addition to a couple of minor patches here and there. One way or another, my welding chops will become better!

[89turbocabmike]

Here's another good welding site:

http://www.weldingweb.com/

[rennch]

Guys, what's the best method for grinding welds? I've got a grinding stone/disc on my angle grinder, but it's really harsh. Is there a better plan?

[Zeke]

Michael, I'm back in the flesh here, so I don't have to use PM's. I just came in from doing just that. Use a grinding wheel to dress down and somewhat shape your welds and then follow with a sanding disc. That will polish out the grinding marks and leave a great surface for painting. I genially use a 50 grit unless it's on the bodywork outside. Then, I will go to 80 before using a DA with same and then maybe a shot with 100.

Sounds like you are building "worms" as you are welding. Time to experiment with some more current and flatten out your welds. It comes with practice and experience, but I still have to make "surface" welds now and then in awkward positions or uneven metal.

There is no substitute for a good welder with infinite controls on both the current and feed rather than a "tapped" machine. You get to where you can walk over an set both for the weld you're anticipating and get right to it. The best welds are the ones the make the least noise and the "bacon sizzling" is nice and smoooooooth.

Edit: As an afterthought, I have to tell you that the machines that have microchips in them for hot starts and then backing down on the current really make for less work. I don't have one yet, but that is the next step for me. The start of a weld and continuing are 2 different things altogether. For instance, when spotting, you should be one tap up from what you would use to run a bead.

[rennch]

Hi Milt,

Thanks for the tips. I think I need to get some more air tools.

I had a good welding day yesterday...got that sizzling bacon sound and really started "getting it". So, my next rust patch should hopefully be better.

[rw7810]

emptyo - I think one of the preferred methods of grinding is with one of the "flapper" disks.