Auto Body Welding and Air Compressors

I'm getting close to cutting out rust and installing panels. I have a Century wire feed welder, MIG and flux-core, will flux core work for auto body? I'm wondering since I don't use this very much I took my cylinder back instead of paying monthly rental. I can do a cylinder lease if necessary but if Flux core wire will work for auto body repairs then I can save some money.

Also, it appears I'll need a more powerful compressor. The compressor I'm most interested in right now is a Porter Cable 60 Gallon 3HP with a Cast Iron pump, these are running $599-$699 on the internet but the local farm stores have them for $399. I figure the 60 gallon tank being brand new would make that hard to beat, unless someone here knows of a better deal.

The Porter Cable 3HP compressor has around 10CFM at 90PSI, I have another compressor with 5.3CFM at 90PSI I can connect together if I need to. Also I have another compressor with around 3HP with a hole in the tank. Anyway, if I bought the $399 compressor with the 60 gallon tank, I could couple 2 more compressors and get close to 25CFM if I needed to.

RogerN

Reply to
RogerN
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Can you have owner bottles?

Thats like an equivalent of a 5 HP compressor. If you look around, you can find a decent 5 HP compressor, it will work forever and supply enough air.

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Reply to
Ignoramus12901

Yeah, something like that anyway, lifetime lease or something like that. But if flux core wire will work just as well it would save me maybe $200 for the tank and gas.

In all I could hook up 2ea 3HP compressors and a 1.5HP compressor to get around 25CFM, I usually don't see over 18CFM maximum from 5HP compressors, though 5HP would be enough for about anything I plan to do, maybe some sand blasting. For the new compressors around here the single stage 5HP are $800 with a 60 gallon tank. At one time Rural King had a Quincy single stage 5HP

60 gallon for ~$600, I'd buy one of those if they were still available. Anyway, an extra $400 to step up from 3HP to 5HP seems steep since they both have 60 gallon tanks. I think I would be better off to buy 2 of the 3HP compressors and have 20CFM + 120 gallons of air tanks!

The portable compressor I have with 3HP and a leaking tank has a 30 gallon tank, pretty big for a portable. I don't like the idea of welding on a tank, it could have some compressor oil in there, might make flamable fumes. If I get energized to disassemble the compressor maybe I'll fill it with water and weld on it.

RogerN

Reply to
RogerN

Reply to
JR North

--Is that Porter Cable air compressor a red-painted vertical one? I got one a few years back and it had some serious teething problems that included sucking an air valve assy that required a visit from a P-C tech to fix. He then said that the valve had to be replaced every few months to keep the thing operating. Have also thrown the drive belt a few times. You might want to look to another brand.

Reply to
steamer

I don't believe 10 CFM at 90 PSI with 3 PS, nor should you.You get what you pay for. Don't buy junk. Steve

Reply to
Steve Lusardi

Roger...mig works nicely with CO2. Im sure you can snag a small Co2 bottle someplace. I get em for little or nothing. Liquid CO2 costs damned little, and a bottle will last for literally hundreds and hundreds of hours of mig welding. A 20lb bottle can be had for less than $50..often far far less..and they are cheap to fill and last a very long time.

It should be noted that Co2 bottles are falling out of favor in bars, soda shops and whatnot as newer tech is employed..and there are literally Millions of them out there.

Just a heads up.

As far as welding with CO2..it does a really nice job, though the welds are not always as pretty as C25 or straight argon..they are as good or better than flux core, and actually make the machine "hotter" so you can weld at a lower power rating. And there is litle or no "clean up" after welding.

Gunner

One could not be a successful Leftwinger without realizing that, in contrast to the popular conception supported by newspapers and mothers of Leftwingers, a goodly number of Leftwingers are not only narrow-minded and dull, but also just stupid. Gunner Asch

Reply to
Gunner Asch

10CFM at 90 PSI seems to be a common rating for 3HP compressors, most other brands have compressor in the same range. Or course all these could be rated with the same amount of wishful thinking though :-) A friend at work has a Quincy single stage 5HP that is supposed to run around 16-18CFM at 90 PSI. I don't actually know anyone with a CFM meter for their air compressor but one of the reviews I read on the compressor said they were able to run two air sanders on the compressor. I just figure it would run most of my air tools, my 5.3 CFM runs most of my air tools, but I could couple it up with the 5.3CFM if it has trouble keeping up.

RogerN

Reply to
RogerN

I'm hoping Iggy can find me one of these for maybe $25 though. Probably cost me $1000 for a drive and wiring though!

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Reply to
RogerN

On 06/27/2010 08:46 AM, JR North wrote: (top posting fixed)

(compressor stuff snipped)

Or hammer weld it with oxy-acetylene. Not that this is a trivial skill

-- it may take you less time to get a part-time job at McDonalds & save up for a TIG welder than it would take you to learn how to hammer weld a really good seam with oxy-acetylene. But it can be done.

Reply to
Tim Wescott

I haven't seen that done for 30 years, but someone who was expert at it tried to teach me once upon a time. He largely failed, or I just failed to learn. d8-)

It takes a lot of practice and a fine feel to know how much to "splash" the metal toward the weld with hammer and dolly.

I thought this was a lost art, and that everyone did this work with MIG these days, hammering down the bead a bit and then just grinding it off? It introduces a lot less total heat than TIG, and a great deal less than O/A.

Reply to
Ed Huntress

I already have a TIG welder with a 350A liquid cooled torch. All the stuff I see on auto body is saying MIG weld, that oxy-acetylene and TIG makes too much heat in the panel and causes warping. I loved oxy acetylene welding in school, you could see what you were doing, welds were very solid, no slag to fight... but from what I have heard it doesn't work for modern automobiles, hopefully that's wrong.

RogerN

Reply to
RogerN

Oh, _modern_ automobiles...

I only ever learned oxy-acetylene welding, and that a long time ago and only to the stage where I was told that with lots more practice I should be really good.

I'm surprised that MIG is supposed to be better than TIG, but as I said I've been out of the loop.

Reply to
Tim Wescott

I'm surprised to hear that it's thought that TIG puts in too much heat compared to MIG. My choice would be TIG and butt welds but that's my preference, on long joins at least. I'm not doing it for a living mind you. The longest external panel join I've done, read visible, was about

2' or a bit more letting in the bottom sill section of a rear wing on a Lancia Beta HPE. Usual procedure of tacking every couple of inches, hammering the tacks to counter contraction and keep the gap constant, then weld between the tacks and again hammer the weld. End result required very little filler in a few spots. I find that while MIG is quick you can then spend quite some time grinding back the weld and need to be careful doing it so as to not distort the panel from the grinding heat. For some shorter welds up to maybe 10" I have used MIG hot and fast and run a single weld in one pass to good effect but still care needed in the grinding.

BTW I've rarely used gasless and generally have heard it's not good for auto body sheet metal as it runs hotter and is more prone to burning through.

Reply to
David Billington

The excess heat and consequent distortion is the problem with O/A. I can do hammer welding, or could at one time, but MIG and TIG make life so much simpler.

Reply to
Don Foreman

I've done a lot of rust work back in the day. I will make two suggestions based on my experience:

1: forget flux core, go with Ag25. (25% CO2, balance argon) 2: lose the Century and get a Lincoln SP125+ (or whatever model is current now) with continuous heat control. That continuous control makes a huge difference on thin steel. 3: if you don't have one already, get an autodarkening helmet

The relatively minor cost of having the right tools will repay you many times in labor savings and satisfaction with results.

I have TIG but never used it on autobody. MIG is the right tool for thin steel panels and autobody plug welds.

I have 14.4 CFM at 90 PSI, never ran out of air doing autobody work.

>
Reply to
Don Foreman

I've not used straight CO2 so I won't knock it, but "hotter" is not a feature when welding 24-gage steel.

When considering the time spent and cost of good materials (paint, etc) for a decent job, the cost of Ag25 mix is completely insignificant, probably less than the cost of electricity to run the compressor doing all the sanding and grinding.

Reply to
Don Foreman

The century I bought many years ago has continuous heat control and continuous wire speed control. It is a ~140A 240V model, got it new for $500 when the 120V models were about half that. It came with the regulator for gas.

Those sound nice, my old school involved a 150W light bulb right next to where the arc was being struck, allowed you to barely see what you were doing.

Thanks for the info!

RogerN

Reply to
RogerN

But you can indeed turn it down to the next lower range in most cases...giving you plenty of welding ability and for cheap. But yes..C25 may be better if you have it. Trimix would work as well. But..its pricey

Your advice is noted.

Thanks!

Gunner

One could not be a successful Leftwinger without realizing that, in contrast to the popular conception supported by newspapers and mothers of Leftwingers, a goodly number of Leftwingers are not only narrow-minded and dull, but also just stupid. Gunner Asch

Reply to
Gunner Asch

What is the ultimate? Perhaps auto bodies should only be welded 5032.1 feet deep in fresh water at a temperature of 72.549 degrees F with a certain PH? Didn't work, what kind of hat were you wearing? Ok, I'm being ridiculous, but like you say, if CO2 is hotter then perhaps you can turn the amps down, or maybe the flow up, or have it cooled otherwise... I dunno, but I doubt that the best method is any more than someone's trial and error that they had success with.

RogerN

Reply to
RogerN

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