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Author
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Topic: which welder should i use?
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thumpin cat
Gearhead Posts: 142
From:
Registered: Mar 2002
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posted 02-02-2003 12:43 AM
  
i need to weld a roll cage and i have a small mig welder should i weld the roll cage with that or should i buy a 140 amp arc welder to do the job ?please let me know thanks a lot.
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Dubz
Gearhead Posts: 324
From: Manitoba Canada
Registered: Oct 2002
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posted 02-02-2003 01:31 AM
i would like to know this also as i am building a roll cage with a JD2 bender .... and what thickness of tube is used for a roll bar?
.120? .100? and is it erw or dom?------------------
1974 Gran Torino, 351W Just a young buck
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Bloose
Gearhead Posts: 219
From: Milwaukee, WI
Registered: Dec 2001
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posted 02-02-2003 05:09 AM
No expert here but, my personal first choice for welding a cage would be TIG, then MIG. The only thing with the MIG is you need enough current to get penetration. Real penetration not just a pretty weld. TIG's are pricey and a bit slow going, but I persoanlly beleive well worth it. I would not MIG weld a cage with anything but a 220V MIG. The Miller 175's would do the job. But like I said I am no expert.Dubz, Don't know what wall is recommended but definitly DOM. B-loose
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n2oMike
Gearhead Posts: 1420
From: Spencer, WV
Registered: Jan 2001
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posted 02-02-2003 09:04 AM
NHRA rules state a mild steel roll cage must have a minimum thickness of at least 0.120". (I believe... it's at least that)Most shops that sell cages use 0.134" wall thickness tubing to be safe. When tubing is bent (especially mandrel) the outsides of the bends can get stretched out and thinned. So, use the thicker stuff to be safe. If money is not really a problem, Cro-moly steet cages only have to be around 0.080" thick, but the welding is much trickier, and MUST be done with a TIG. As for welding mild steel, if you use a 110V unit (and it's at least 100amps), be sure to have the heat turned up all the way, and use 0.030" wire! The thicker wire will burn in a lot deeper than the 0.023" that many people use for thinner metals. (This is for solid wire, not flux core.) Good Luck! ------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220 [This message has been edited by n2oMike (edited 02-02-2003).]
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steve'66
Gearhead Posts: 5897
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 02-02-2003 02:16 PM
I agree with Mike, except for the 120V mig welder. You'll be waiting all day for the welder to cool. You need a higher duty cycle like the Miller 175 or better.  Also, don't used flux cored wire inside your car. You'll have weld spatter on everything.SteveW
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n2oMike
Gearhead Posts: 1420
From: Spencer, WV
Registered: Jan 2001
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posted 02-02-2003 03:02 PM
A buddy of mine has a Lincoln 100amp machine (that uses gas, flux core sucks) and he welded in a roll cage with it turned all the way up with 0.030" solid wire. It worked just fine.Now, if you are wanting to weld continuously with that machine turned up all the way, it will get hot and kick off... and you'll have to wait until it cools before continuing. But, roll cage welding is not generally continuous. A joint is welded, then you wait a while before doing the next one. I don't see a problem welding a cage in with it, but it's not a good choice for 'production' work, where it will be in constant use all day. Also, keep in mind, 0.030" flux core is not equivalent to 0.030" solid wire. (used with gas) The flux core wire is hollow, and is equivalent to thinner wire. Cat, you mentioned using an ARC welder as an alternative. I imagine you are referring to a 'stick' welder. Unless you are a GOOD, and EXPERIENCED stick weldor, stay with a MIG machine for roll bar work. Stick welders take a LOT more practice to get good with. I agree with Steve66 in the fact that the 220V Miller is an EXCELLENT machine. I wouldn't mind having one myself. Miller is at the top of their field, and produce fantastic products. However, a decent 110V MIG (using gas) will do a fine job on a roll cage when cranked up all the way with 0.030" solid wire, as long as it's given a little time to cool between joints. Good Luck! ------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220
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RonnieT
Gearhead Posts: 493
From: Port Allen, La. 70767
Registered: Jun 99
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posted 02-02-2003 03:52 PM
I am not up to date on teh NHRA rulings but I thought a Stick welded cage was not permited. I know a fellow that just spent a ton of money having a homemade stick welded cage removed and replaced with a TIG welded cage.------------------
Ronnie
69 mach1 351W-4V engineless at the time!
70 Torino GT 351C-4v with a "shaker"
Mustangs and More Member #23
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Just Strokin
Gearhead Posts: 754
From: Tuscaloosa, Alabama
Registered: Dec 2001
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posted 02-02-2003 05:29 PM
Stick welders are NOT allowed in welding mild steel roll bars or cages. Mig or Tig. Tig is the only welding allowed on chrome moly cages/frames/etc.------------------
Larry No fast Fords at this time but one fine cruising 96 F350 CC DRW Power Strokin diesel.
And one rusty 64 Fairlane nick-named the Rust Bucket....And sometimes called the Money Pit... The sounds of a brain dropping into gear.....
"Buzzzzzz.......Click" [This message has been edited by Just Strokin (edited 02-02-2003).]
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steve'66
Gearhead Posts: 5897
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 02-03-2003 12:31 AM
Yeah Mike,We used a Miller 250 for Melissa's roll bar and it didn't miss a beat. But my son did the welding and that's his trade. He's got a few roll bar/cage side jobs lined up, but they are more work than people want to pay for.  SteveW
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Dubz
Gearhead Posts: 324
From: Manitoba Canada
Registered: Oct 2002
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posted 02-03-2003 02:41 AM
allright, so i would be safe with .120 wall DOM and a 110 MIG
and not just pretty weld, the discoloration is an indication of the penetration. the welder is at it's max heat setting, with .030 wire but it has also managed penetration. http://groups.msn.com/TheMINIHummer/customfrontbumperwinchplate.msnw? action=ShowPhoto&PhotoID=1276 and this is on 3/16" plate.
http://groups.msn.com/TheMINIHummer/customfrontbumperwinchplate.msnw?action= ShowPhoto&PhotoID=1278 ------------------
1974 Gran Torino, 351W Just a young buck
[This message has been edited by Dubz (edited 02-03-2003).]
[This message has been edited by Dubz (edited 02-03-2003).]
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Bloose
Gearhead Posts: 219
From: Milwaukee, WI
Registered: Dec 2001
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posted 02-03-2003 04:35 AM
Again, no expert here but to my untrained eyes those welds look pretty nice. Much better than a lot of the other MIG welded cages I have seen. I still love TIG though, because even a hack like me can do nice, strong, good looking welds with some practice. When you coming to do a cage for me??? Welding is the easy part for me (have access to a TIG welder), bending it would be the tough part. B-loose
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n2oMike
Gearhead Posts: 1420
From: Spencer, WV
Registered: Jan 2001
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posted 02-03-2003 10:30 AM
quote:
Originally posted by Dubz:
allright, so i would be safe with .120 wall DOM and a 110 MIG
Those welds look good to me! As for using 0.120" wall tubing... If you ever plan to run in the 9's, and need to get the car certified, they will check the thickness of the cage at various points. I believe the MINIMUM wall thickness is 0.120". When tubing is bent, the outside wall tends to get stretched, and when it stretches, it thins out a little. There are a couple guys, Ron Feddema for one, who had cages built with 0.120" material that recently dipped into the 9's. Ron went to get his cage certified, only to have it rejected for being too thin in spots. He had to have the whole cage done over again. drag79stang over at fordmuscle.com is going through this as well. If you don't need to get the cage certified (unless you go 9's or faster, chances are you won't) you can probably get away with 0.120" wall. I'd probably play it safe and go with 0.134". Good Luck! ------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220
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662+2
Journeyman Posts: 64
From: Ontario, Canada
Registered: Jan 2003
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posted 02-03-2003 11:36 AM
If I was building this cage to save my life I have no doubt in my mind, for piece of mind TIG is the way to go. Just my two cents Good Luck!
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NoBS
Journeyman Posts: 34
From:
Registered: Oct 2002
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posted 02-03-2003 09:54 PM
n2oMike touched on an answer for my question, How do they 'know' when it's a homebuilt? Ultra sound the cage where they think it may be thin? Bill of materials? If a shop did it would they want a signed affidavit from the welder and a copy of the welders certs? I have pretty much the same questions about fuel cells, does the welder have to be certified in pressure vessel? Like Bloose I have access to a TIG. Also a mig, stick, plasma torch, and a bunch of other toys, I mean, Tools. And a mid-life crisis is staring me in the face.  I have lists of things I've built and repaired, but this car certification is new to me.
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bfxcomet
Gearhead Posts: 535
From: Port Alberni, B.C. , Canada
Registered: Mar 2001
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posted 02-03-2003 09:57 PM
I looked at your pics, The 1 with tubing welded to pl was unable to tell anything but that is the simplest weld to do. Getting enough penetration with 110V welded on 3/16 is pushing the max for that machine. Make sure you grind the suface before welding so that there is no mill scale which will limit penetration.
The tubing to tubing you can see where the stop starts( where the welds overlap)there is vey little dicolouration from heat. That is because the first weld is assorbing the heat from the second weld, so it is cold lapping, which is bad. You can help this by grinding the stop/starts before you place your second weld.
I have said it before that I would not do this without at least a 220V welder.
As for Tig welding if your a good welder great but if your slow moving you can be doing bad damage from a large heat affected zone.
My last 2cents again about welding if it is a suspenion part or a cage that is to used to safe your life, spend the cash or make a new freind and get a proffesional to do the job.
Good luck
Roger------------------
65 comet project
84 T-bird 302/C4 14sec street/strip
Made in CANADA built for speed
#1145
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67coupe
Gearhead Posts: 350
From: dallas NC usa
Registered: Nov 2000
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posted 02-03-2003 10:03 PM
i personally wouldnt do a cage with a 110 machine ive got a 155 lincon 220v machine and with .030 wire it does deacnt on cages ive welded in one so far with it (oh the 110v oppinion mayby cuz im used to the 3 phaze 300amp machines i have at work) ------------------
Josh
67 coupe with 351c
8.41 in the 1/8
1.90 60'
at 82.03 mph
94 Explorer
30 model A currently rustbucket
in process 67 convt with efi 5.0 and t5
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Dubz
Gearhead Posts: 324
From: Manitoba Canada
Registered: Oct 2002
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posted 02-04-2003 12:26 AM
quote:
Originally posted by bfxcomet:
The tubing to tubing you can see where the stop starts( where the welds overlap)there is vey little dicolouration from heat.
over half the tube is discolored from the heat of the weld....i'm not sure i understand what you are getting at.... ------------------
1974 Gran Torino, 351W Just a young buck [This message has been edited by Dubz (edited 02-04-2003).]
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TomP
Gearhead Posts: 4709
From: Delta BC Canada
Registered: Dec 99
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posted 02-04-2003 01:05 AM
Those looks pretty good. The .120" DOM is much more accurate than the ERW stuff... the NHRA minimum of .118" should be met without problems. Thing to watch for with a mig is a cold weld, you can make a pretty decent looking weld that simply doesn't stick to one surface. You should observe both pieces turning orange as you weld. In the case of a too-small welded you can even preheat the area with a propane or oxy-acetylene torch to make a better weld.
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