welding

[scampy72]

hey guys im gonna start rying to weld with OXY/MAPP cause i just cant affor a welder right now and i have a torch. so my question is simple, any tips? especially on the best way to prevent warpage. as always any help is great!

thanks
marc

 

[Woods74]

Doing sheet metal work are we? I'm a beginner, right in the middle of the same deal. Here is some information that may help.

I'm using the cheap Harbor Freight flux core welder, with a 600w dimmer switch wired into a 100' Extension cord. I have to cool the tack welds right after with air for about 10 seconds. I weld from the outside in, and skip weld around the panel like lug tightening on a wheel. After you get dialed in, it works like a charm. You can either use a air compressor, or a shop vac with a dimmer switch like I am to cool your welds. ;)

As a side note, I don't know which panel your fixing/replacing, or if you've sourced your sheet metal yet. My dart sheet metal is 20 ga all around (that I know of). It was put to me that 22 is usually too thin, 20 is good for bending, 18 is fine, less prone to blow through, 16 is structural. Matching the ga will usually make it easier to weld.

If you haven't sourced your material yet, take a mic, or a set of feeler gauges with you to verify thickness when you do.

Here are the numbers for the various thicknesses, ripped off from the moparts board:

Cold Rolled Steel thicknesses:

- 16ga = .0598"
- 18ga = .0478"
- 20ga = .0359"
- 22ga = .0299"
- 24ga = .0239"

Satin coat or galv. sheet

- 16ga = .0635"
- 18ga = .0516"
- 20ga = .0396"
- 22ga = .0336"
- 24ga = .0276"

Happy trails on the many, many hours of work ahead of you.

 

[scampy72]

thanks for the info. im using old fenders that i have so i can match the guage, im doing work on the quarters. flux core is good, mig w/e i wish i could afford to buy one, itd be easier since im use to it. but i already have all the stuff to weld with the oxy/mapp combo so thats what im trying to figure. i know that there is a larger chance of warpage due to the flame so thats why i need the help.

 

[67Dart273]

I'm using the cheap Harbor Freight flux core welder, with a 600w dimmer switch.

I CANNOT SAY ENOUGH against this "procedure." A dimmer chops up the AC wave, and that welder has circuits that are DESIGNED to operate on 120V AC, not some voltage less, especially something that is not a sine wave

YOU COULD very well damage or fail the control boards/ circuits in the welder.

Additionally, it probably has a transformer power supply which is ALSO not designed to operate downstream of a dimmer.

 

[Woods74]

I CANNOT SAY ENOUGH against this "procedure." A dimmer chops up the AC wave, and that welder has circuits that are DESIGNED to operate on 120V AC, not some voltage less, especially something that is not a sine wave

YOU COULD very well damage or fail the control boards/ circuits in the welder.

Additionally, it probably has a transformer power supply which is ALSO not designed to operate downstream of a dimmer.

Thanks for the warning, You aren't the first one to get riled up over this "procedure". There was a big to do on the Hobart forums about it. I understand what I'm doing. The story is: A guy over on the old volkswagon fourms was working with this welder on thin gauge bug panels for months and months with no problems. It's working great for me and my machine.

 

[67Dart273]

Sounds to me like the Hobart guys were trying to give you good advice. Do you have ANY idea how MIG welders operate? This would be, example, the same difference as trying to operate your refrigerator on a dimmer. Don't be surprised when it dies one day.