Welding Multi Question

[Tunnelratt]

I can stick weld, but never have worked on sheet metal, I have a lincoln stick welder for the thicker material, so recently picked up a lincoln sp 125 mig, for the thinner stuff, so I need to learn sheet metal, for now I will work without gas, ( I need to get the gauges) I figure the best way to practice would be to get a clean 55 gal drum, cut holes in it then put the patches back, figured the wife wouldnt appreciate an old drum sitting around so I found a clean old wheelbarrow, pretty heavy gauge metal, so will do the same, and when I am done will just wheel it to the curb,here are my questions.

1. What gauge metal is used on our cruisers, FJ 40?
2. What size flux core wire should I be using ?
3. Is fittment critical on sheet metal, I will probably use a cut off wheel to make the holes, or a plasma cutter, the cut may be to wide, I guess I could just weld 2 of the sides back in place, its only practice

4. Sorry, random rambling, any advice, I guess I just need to burn some wire


Steve

 

[Tunnelratt]

Well, OK, figured it out, cutting holes of random shapes and sizes with a plasma cutter leaves a very small gap to fill, so I am able to just reinstall the cut portion, using the old wheel barrow is a great idea, the gauge of steel is pretty close to that of the cruiser and you can move the thing around, lay it on its side, cut, weld, then just put it away, I am using .030 flux core wire, speed about 2.5/3, not to hot, it spatters more that I like so picked up some anti spatter spray, stuff works pretty good. When I get done cutting and patching and practicing I can start on the cruiser

 

[fj40charles]

Make sure you grind off the dross from plasma cutting. It will cause a lot of problems in your weld.
Personally, I'd use solid wire for thin sheet metal.

 

[ontherox]

you totally need to get some gas and get rid of that friggin flux core crap,it really is a world of difference - especially on sheet metal.There really is no point in even learning with flux core...it sucks balls!!

This is your welding on core wire:

This is your welding on solid

A complete exaggeration really but just to give you an idea of the difference.

 

[brownbear]

Welding on the cruiser is not like a wheelbarrow. The expanse of metal will show warps pretty quick.

The only way to weld is to spot weld. Always going back and forth, never staying in one spot too long. If you try to run beads you will warp the sheet metal.

2-4 on the wire, and A on the other dial. Short blasts are what you do. Keep the welds tiny. No lumps. The grinding is too much. Use a rough grinding disc, like a sand paper disc on a die grinder. Do not stay in one spot too long with the grinding, same heat issue.

I also used a wet cloth to cool the area as I worked.

Also don't weld any areas if you can't get to the backside to clean and paint. It will only rust again. Rather use structural adhesive and tabs in behind to do a flush patch.

All of my welds on sheetmetal I was able to sandblast after grinding it down on both sides of the metal. I then POR-15 the area to seal it up. Welds are the rustiest metal there is.

.023 wire and a C02 gas is needed. .30 wire will be too think IMOP

 

[Tunnelratt]

At this point I think I am 100% with you guys, gas is probably the best way to go but need to buy the gauges and a bottle, not ready yet $$$$, 10-4 on the cooling aspect of moving around the patch, wont run any beads.
Right now I just need to get some time burning wire and getting used to the machine.
brownbear, good info thanks

ontherox, please tell me that was from a PO

fj40charles, its been about 8 years since I even fired up the plasma, It's a Miller Spectrum 300, 115/240, set for 240, jeeze that thing is fun! dross? Is that what you call the raw edge after cutting?

Thanks Guys

 

[fj40charles]

dross? Is that what you call the raw edge after cutting?

Yes. Dross will have all kind of contaminants in it and will cause problems when welding.

 

[kulangot]

Here is my 2 cents:

"Fit is it, tight, clean, shiney and bright"

For good sheet metal repair, you need to get the metal so that it fits up super tight with no gaps and is so clean that there is nothing but white, clean and bright metal. A great trick is get the metal as tight as you can, spot weld it and then tighten up the gaps after spot welding with a small cross peen hammer backed with a dolley behind it.

Best not to use a wire wheel to prep, they spread contamination.

Griding disc removes too much metal, use a flap disc or a flexible disc. I like variable speed grinders and they can run slower and put less heat into the metal. If you lay down too much metal and have to grind it off, that heat can also warp the metal.

I do not think cooling with a wet rag is a good idea as it causes cracks in welds and shrinks the metal. I do use a wet rag to fix oil can dents and high spots, but not when I weld. Just my opinion.

Like bear said, .023 or .025 and 75/25 mix and if you enclose and area you must use weld through primer.

Mark out the metal in one inch increments and tack together with a very small BB or "Red Hot" candy sized tac weld.

Then go back and lay down a stick of spot welds. Here is how I do it, put down one tac weld. Wait for it stop glowing in your mask and then put down another, wait for it to stop glowing red and then repeat. This is one of the reasons that I do not like auto darkening masks. Do one inch at a time and then move to the furthest area from the weld and come back when its cooled down. If done this way, you will have very minimal distortion.

Here are two pics that show what I am talking about. I don't think this type of interrupted welding is appropriate or strong on structural welds like cages, but is a great technique for sheet metal (I see it on cages all of the time - opinions on this ?). Same thing goes for vertical down welds, not safe on structural plate, but ok for sheet metal 11g or thinner.

Have fun with it. Take your time, it's actually pretty easy if you don't hurry.


-Stumbaugh

 

[94cruisercal]

Tunnelratt - Some good suggestions here. I would agree with the .023" solid wire and mixed gas. Remember to change polarity when you switch from FCAW to GMAW


EDIT - You may try E6013 rods in your A/C stick machine. small diameter 1/16-3/32. These electrodes were designed for light sheet metal work

 

[ontherox]

ontherox, please tell me that was from a PO

LOL yeah,i pulled that one off my subaru and made the new one.