Sheetmetal Work - The 1947 - Present Chevrolet & GMC Truck Message Board Network

wxman1 · 07-28-2003, 10:42 PM

I am attempting to do some sheetmetal
repair..specifically welding in patches of
new metal to replaced rusted out sections.
So, I just bought a Lincoln Electric Model
135 wire fed MIG welder. I got some 18 guage
sheetmetal to practice with. I'm using setting
B-2 which is what the unit calls for given 18
guage material. I'm using .035 flux cored wire, no gas. Well, I am continually burning through the work. The welds look spotty with burn through holes about every inch or so. Is there
some trick to this or maybe I just need more
practice. I seem to have better luck with 16
guage sheetmetal.

Any advice/references/hints is appreciated!

Jim
Mt Juliet

GMCrazy · 07-28-2003, 11:04 PM

im not an expert welder by far, but the first thing i would do would be to turn the amperage down. sheet metal is very aggrivating to weld, so you definately need lots of practice; play around with different wire/metal/amperage, that's got to be the best way to learn. best of luck to yuh!

Southpa · 07-28-2003, 11:05 PM

Its very difficult to maintain a steady bead with 18 ga. sheet. You could wind up dumping too much heat into the general weld area causing blow thru and warpage. Running high heat for 18 ga. (roughly above 90 amps) means you have to move faster. I've been welding on and off for 10 + years and I still can't weld fast AND clean, so take your time. Heres how.

Try "fitting" the piece with lots of tacks (no more than 1/2" long), ensuring that they are evenly distributed. Then continue tacking in between the previously made tacks and so on. Keep moving around so places welded can cool off. Also, try going a bit less on the amps/volts. Experiment a bit and see where that fine line is where you can strike a continuous arc and where the electrode (wire) sticks to the metal. But you still want enough heat to get good penetration and make solid welds.

One more point, .035 flux core is considered a bit large for 18 ga. Thats unfortunate, because you need x amount of amps and volts to run the stuff efficiently, ie. making quality welds, and I think .035 flux core is the smallest you can get. Does your Lincoln have the option to use shielding gas and microwire? Smaller diameter wire is available and you can tone down the amount of heat required to make it work.

I'm sure you're going to get lots of input from others here and I could name a few more things that are important. travel speed, tip angle and distance from work, and cleanliness of base metal all come to mind. But it CAN be done, just takes practice and familiarity. I did all my sheetmetal work with a stick welder.

Johns70 · 07-28-2003, 11:54 PM

i have a lincoln 110v wire feed welder and i have good luck with it useing smaller flux core wire, no gas.you can't do a continous arc with it doing sheet metal, like southpa said you have to spot weld it here and there intall all the spot welds are connected.

**1971Stepside** · 07-29-2003, 04:37 PM

You are using to big a wire. I have the same welder and I was trying to use .35 and it would just burn holes. I bought the flux core .23 wire and it works great. I set mine on C or 3 can't remember the specific letter or number and the wire feed on about 5.5 to 6. Works great! Get new wire and the gas and you will like your welder again!!

slogo · 07-30-2003, 10:21 PM

also use compressed air right after eash pass to help cool and stop wrapping of metal

JHickson6 · 07-31-2003, 12:23 AM

i rented a lincoln 135 to do some body repairs on my bus, man what a waste of time, i gave up, it just kept blowing through. Even our experienced shop welder got frustrated. Well i just got my brand spanking new Lincoln Power Mig 255 running with a Co2 Argon mix, Wow what a difference the gas makes, flux cored wire is garbage unless you're doing heavier metal. But i'd swear i could weld the thinest sheetmetal without a blow through! Go gas, it's not worth the frustration.

My 2 cents

krazy_texan · 07-31-2003, 12:45 AM

practice, practice, practice. that is all you can do it does not sound like you are doing anything wrong , but I will tell you that you will eventually learn how to fill the holes that you make, but you will get it down if you practice.

wxman1 · 08-01-2003, 03:49 AM

Thanks to all for the advice on welding.
I switched to .025 non flux wire and
got a bottle of MIG gas. Now I can
weld/spot weld sheetmetal (18 ga)
and not burn through. Probably the best
advice was to weld small spots alternating
the location to prevent heat buildup.

Thanks All!
Jim
Mt Juliet

*Gee_Emm* · 08-01-2003, 06:40 PM

Hey Jared, that big blue bus doesnt happen to have a big speaker mounted on top of it?

07-28-2003, 10:42 PM	#1
wxman1 Senior Member Join Date: May 2002 Location: mt juliet, tennessee, usa Posts: 237	Sheetmetal Work I am attempting to do some sheetmetal repair..specifically welding in patches of new metal to replaced rusted out sections. So, I just bought a Lincoln Electric Model 135 wire fed MIG welder. I got some 18 guage sheetmetal to practice with. I'm using setting B-2 which is what the unit calls for given 18 guage material. I'm using .035 flux cored wire, no gas. Well, I am continually burning through the work. The welds look spotty with burn through holes about every inch or so. Is there some trick to this or maybe I just need more practice. I seem to have better luck with 16 guage sheetmetal. Any advice/references/hints is appreciated! Jim Mt Juliet

07-28-2003, 11:04 PM	#2
GMCrazy David Tye Join Date: Jul 2003 Location: Abbeville, Alabama Posts: 52	im not an expert welder by far, but the first thing i would do would be to turn the amperage down. sheet metal is very aggrivating to weld, so you definately need lots of practice; play around with different wire/metal/amperage, that's got to be the best way to learn. best of luck to yuh! __________________ David -68 GMC w/327

07-28-2003, 11:05 PM	#3
Southpa Registered User Join Date: May 2000 Location: Victoria, BC, Canada Posts: 2,410	Its very difficult to maintain a steady bead with 18 ga. sheet. You could wind up dumping too much heat into the general weld area causing blow thru and warpage. Running high heat for 18 ga. (roughly above 90 amps) means you have to move faster. I've been welding on and off for 10 + years and I still can't weld fast AND clean, so take your time. Heres how. Try "fitting" the piece with lots of tacks (no more than 1/2" long), ensuring that they are evenly distributed. Then continue tacking in between the previously made tacks and so on. Keep moving around so places welded can cool off. Also, try going a bit less on the amps/volts. Experiment a bit and see where that fine line is where you can strike a continuous arc and where the electrode (wire) sticks to the metal. But you still want enough heat to get good penetration and make solid welds. One more point, .035 flux core is considered a bit large for 18 ga. Thats unfortunate, because you need x amount of amps and volts to run the stuff efficiently, ie. making quality welds, and I think .035 flux core is the smallest you can get. Does your Lincoln have the option to use shielding gas and microwire? Smaller diameter wire is available and you can tone down the amount of heat required to make it work. I'm sure you're going to get lots of input from others here and I could name a few more things that are important. travel speed, tip angle and distance from work, and cleanliness of base metal all come to mind. But it CAN be done, just takes practice and familiarity. I did all my sheetmetal work with a stick welder. __________________ 1970 GMC 1500 Custom Original 350/TH350 Victoria, BC, Canada You can wish in one hand and crap in the other. See which one gets filled first.

07-28-2003, 11:54 PM	#4
Johns70 Registered User Join Date: Dec 2001 Location: Spring Creek, nevada. U.S.A. Posts: 456	i have a lincoln 110v wire feed welder and i have good luck with it useing smaller flux core wire, no gas.you can't do a continous arc with it doing sheet metal, like southpa said you have to spot weld it here and there intall all the spot welds are connected. __________________ 69 chevy short wide box project 70 GMC jimmy project

07-29-2003, 04:37 PM	#5
1971Stepside Almost Satisfied Join Date: Mar 2002 Location: Springfield, MO Posts: 2,932	You are using to big a wire. I have the same welder and I was trying to use .35 and it would just burn holes. I bought the flux core .23 wire and it works great. I set mine on C or 3 can't remember the specific letter or number and the wire feed on about 5.5 to 6. Works great! Get new wire and the gas and you will like your welder again!! __________________ 1971 C10 Stepside. LSx 6.0 with BTR Stage IV, Speed Engineering Headers, 4L80e transmission w/3200 Circle-D Stall. 3.73. Posi. Purchased this truck when I was 17. I started the rebuild (or take apart) in 1993. I have drug it around all over the country in pieces. Finally back on the road in 2021. "I can't complain, but sometimes I still do. Life's been good to me so far."

07-30-2003, 10:21 PM	#6
slogo Registered User Join Date: Mar 2003 Location: Morristown,TN Posts: 482	also use compressed air right after eash pass to help cool and stop wrapping of metal

07-31-2003, 12:23 AM	#7
JHickson6 I Love This Stuff! Join Date: May 2002 Location: Winnipeg, Manitoba, Canada Posts: 739	i rented a lincoln 135 to do some body repairs on my bus, man what a waste of time, i gave up, it just kept blowing through. Even our experienced shop welder got frustrated. Well i just got my brand spanking new Lincoln Power Mig 255 running with a Co2 Argon mix, Wow what a difference the gas makes, flux cored wire is garbage unless you're doing heavier metal. But i'd swear i could weld the thinest sheetmetal without a blow through! Go gas, it's not worth the frustration. My 2 cents __________________ My Rides 1967 C10 In Pieces for now 1985 Ford B700 SourPuss Bus - BIG BLUE 2003 Silverado CITY WORKER YELLOW!!

07-31-2003, 12:45 AM	#8
krazy_texan Registered User Join Date: Oct 2002 Location: West Des Moines, Ia Posts: 3,233	practice, practice, practice. that is all you can do it does not sound like you are doing anything wrong , but I will tell you that you will eventually learn how to fill the holes that you make, but you will get it down if you practice. __________________ Krazy Texan My Trucks are made with Wrenches not Chop Sticks 1967 GMC 3/4 ton "Johnny Cash" 1990 v1500 suburban 1967 Ford f100 Swb 4x4 "green bean" GOD BLESS JESUS, JOHN WAYNE, AND THE ALAMO

08-01-2003, 03:49 AM	#9
wxman1 Senior Member Join Date: May 2002 Location: mt juliet, tennessee, usa Posts: 237	Thanks to all for the advice on welding. I switched to .025 non flux wire and got a bottle of MIG gas. Now I can weld/spot weld sheetmetal (18 ga) and not burn through. Probably the best advice was to weld small spots alternating the location to prevent heat buildup. Thanks All! Jim Mt Juliet

08-01-2003, 06:40 PM	#10
Gee_Emm Account Suspended Join Date: Sep 2000 Posts: 4,002	Hey Jared, that big blue bus doesnt happen to have a big speaker mounted on top of it?



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