Hey guys, been using my mig abit lately and I found its much easier and I get much better looking welds if I do lots of spot welds in quick succession next to each other... This gives me neat welds almost like TIG with the little circles (moon shapes) all in a line...
Is there anything wrong with doing it this way? obviously its slower and id say its possibly not getting as much penetration... on the other side it is penetrating but you see a line of dots more so rather then a continuous line..
But so far what Ive been welding isnt really structural at all and and more just a seal.... I guess another disadvantage would be possibility of pin holes if i dont get the welds right next to each other.
I can weld in a continuous line just it doesnt give the neat tig weld sorta of look and it blows through alot easier (1.6mm steel was what I last welded)
So yea any thoughts?
I thinking of using the method for things that are visible, ie custom turbo exhaust manifolds, dump pipes etc but arnt really under much stress
Mig Welding Help?
Started by
_Viper_
, Oct 24 2009 12:48 PM
50 replies to this topic
#2
_nial8r_
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Posted 24 October 2009 - 02:05 PM
HI Clint, using the tacing method is alright to get you piece in to place but i would start to worrie about penertration and pin holes like you said, with the mig try welding in 20 -25mm long welds and then move to another part of the part your welding, if its a small repair try doing a little bit at a time so that it cools down other wise you are gonna warp the metal and also you should be able to weld 20 - 25mm long welds at a time with out blowing through my guess here is that you might have the mig set to high to be blowing through 1.6mm metal or your travel speed is to slow, and last i dont know how much you know about different welding but it seems you know enought to get your self outta trouble but i got tought to use a mig in a forward pushing motion inlike a stick welder were you work towards your self if thats makes any sence at all ?? hope this might help 
#3
TerrA LX
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Posted 24 October 2009 - 02:24 PM
You are too hot if your blowing thru 1.6mm easy.
Turn down the amps till you can get the weld slow enough to look like you want then test if it is strong enough for your needs.
So long as you see a little burn thru on the other side it will be plenty strong.
Turn down the amps till you can get the weld slow enough to look like you want then test if it is strong enough for your needs.
So long as you see a little burn thru on the other side it will be plenty strong.
#4
_torana_umunga74_
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Posted 24 October 2009 - 02:30 PM
and move to different areas like 10 or 15cm away and do the short welds to keep it cool and helps warping too.
#5
wot179
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Posted 24 October 2009 - 02:45 PM
Doing a continual line of tacks should work OK as long as each tack is directed into the tail of the preceding one.
This method can work well on lighter gauge material,as it will minimise distortion.
If done correctly ,you can minimise pinholes,which can be a very real concern on car panels as water will penetrate the pinhole and cause rust to start and bog repairs to delaminate.
That being said,I would not use this method on heavier gauge materials.
Your method should be OK on exhausts,depending upon how you are going about it.
If you could put up some pics of what you are welding and your finished welds I might be able to give you a better analysis.
This method can work well on lighter gauge material,as it will minimise distortion.
If done correctly ,you can minimise pinholes,which can be a very real concern on car panels as water will penetrate the pinhole and cause rust to start and bog repairs to delaminate.
That being said,I would not use this method on heavier gauge materials.
Your method should be OK on exhausts,depending upon how you are going about it.
If you could put up some pics of what you are welding and your finished welds I might be able to give you a better analysis.
#6
_Yella SLuR_
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Posted 24 October 2009 - 06:09 PM
I've gone back to oxy welding for panel work, as you can't plenish MIG welds, they are too hard.
Yup, all that they've said, tack into position first, then isolated 25mm line welds around the panel to control the heat/metal movement.
Yup, all that they've said, tack into position first, then isolated 25mm line welds around the panel to control the heat/metal movement.
#7
View GaragePosted 25 October 2009 - 01:30 AM
I use this method for my exhaust and for some thin panel work, the welder needs to be up a bit higher because you don't get the current flow without continuous wire feed, works well thoughThis method can work well on lighter gauge material,as it will minimise distortion.
...
That being said,I would not use this method on heavier gauge materials.
Your method should be OK on exhausts,depending upon how you are going about it.
#8
Struggler
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Posted 25 October 2009 - 08:43 AM
Like a few others I also use the overlapping tack method on thin stuff like panels and exhaust tube. It allows you to use more heat without blowing through and requires less cleanup to look good.
#9
_Bomber Watson_
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Posted 25 October 2009 - 11:30 AM
Yep im with the last few posts. Overlapping tacks on thin stuff, far easyer.
BUT just one consideration, you mentioned a turbo exhaust manifold as a low stress item, i think you should do a bit more research there.
Cheers.
BUT just one consideration, you mentioned a turbo exhaust manifold as a low stress item, i think you should do a bit more research there.
Cheers.
#10
_chrome yella_
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Posted 25 October 2009 - 11:44 AM
on light panel materials i use a suitable piece of copper sheet and clamp it behind the panel. you can form it to fit any shape and it will prevent blowing holes as easy and makes the weld flaten out and stronger.
#11
_Viper_
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Posted 25 October 2009 - 12:05 PM
you mentioned a turbo exhaust manifold as a low stress item, i think you should do a bit more research there.
I meant compared to something like suspension components or structural parts of the car.
Turbo exhaust manifold only needs to hold the weight of the turbo, part of the exhaust and some of the intake and thermal expansion
#12
_Bomber Watson_
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Posted 25 October 2009 - 04:52 PM
While glowing red hot with pressure inside it.....
If you add everything together an exhaust manifold is probably the highest stressed part of a turbo engine.
Cheers.
If you add everything together an exhaust manifold is probably the highest stressed part of a turbo engine.
Cheers.
#13
_Viper_
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Posted 25 October 2009 - 08:19 PM
Better make sure I have good welds then 
Heres another question, I cut and welded in some GTS guard flutes to my Gemini Guard today using the leap frog tack cool method and was just wondering is there any way to stop/reduce the shrinkage around the welds?
Like i get both the panels perfectly level but sometimes when you weld it then grind it back flush, around the weld is a little lower like its sunken away?
Heres another question, I cut and welded in some GTS guard flutes to my Gemini Guard today using the leap frog tack cool method and was just wondering is there any way to stop/reduce the shrinkage around the welds?
Like i get both the panels perfectly level but sometimes when you weld it then grind it back flush, around the weld is a little lower like its sunken away?
#14
wot179
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Posted 25 October 2009 - 08:23 PM
I dont think you can avoid it with a mig.
Re read what yella said.
Youll just have to plop it up and break out the speed file.
Re read what yella said.
Youll just have to plop it up and break out the speed file.
#15
Posted 25 October 2009 - 08:24 PM
Cooling it slower and hammering the welds can help a little (not so easy with the mig but), hard to avoid it though
#16
TerrA LX
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Posted 25 October 2009 - 08:39 PM
Try not putting too much heat into it, like welding with a copper or alloy plate behind to heat sink.
Also cooling rags help.
Using fresh grinding wheels and not going ape shit, grinding also heats the panel.
As above, you will still need to plenish some with these type of welds.
Also cooling rags help.
Using fresh grinding wheels and not going ape shit, grinding also heats the panel.
As above, you will still need to plenish some with these type of welds.
#17
_Bomber Watson_
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Posted 25 October 2009 - 08:41 PM
As Terra LX says, be carefull when grinding because you can warp panels here also.
Apart from that,
Tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool.
Then, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat,
Basically
.
Cheers.
Apart from that,
Tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool, tack hammer cool.
Then, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat, bog sand repeat,
Basically
.Cheers.
Edited by Bomber Watson, 25 October 2009 - 08:43 PM.
#18
Posted 25 October 2009 - 08:53 PM
I think you missed a step Bomber, there should be another 'tack hammer cool' in there somewhere...
#19
_Viper_
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Posted 25 October 2009 - 10:11 PM
So can you explain the "hammer" part? was never told about that bit in the short course we did.
Is that planishing? and if so what is it and what do i I do exactly... and what does it achieve
Is that planishing? and if so what is it and what do i I do exactly... and what does it achieve
#20
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Posted 25 October 2009 - 10:25 PM
When you lay a weld, it expands,
when it cools, it contracts.
Sometimes it contracts more than the surrounding substrate so you need to stretch the weld with a hammer and dolly, this will bring the panel flat again if the sink is caused by the "heat shrink" of the weld.
when it cools, it contracts.
Sometimes it contracts more than the surrounding substrate so you need to stretch the weld with a hammer and dolly, this will bring the panel flat again if the sink is caused by the "heat shrink" of the weld.
Edited by TerrA LX, 25 October 2009 - 10:28 PM.
#21
_Viper_
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Posted 25 October 2009 - 10:40 PM
Ok So tack, then quickly whip out planishing hammer and dolly with dolly on the rear and give it a few taps? Do I have to be quick or can do a few tacks apart from each other and have abit time to hit em?
Cheers for the info btw guys... Im actually a construction worker. everything ive learnt to do is just from DVD's and forums (you guys) oh and I did a short night course at tafe for 6 weeks which covered basics.
Cheers for the info btw guys... Im actually a construction worker. everything ive learnt to do is just from DVD's and forums (you guys) oh and I did a short night course at tafe for 6 weeks which covered basics.
Edited by Viper, 25 October 2009 - 10:42 PM.
#22
TerrA LX
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Posted 25 October 2009 - 11:10 PM
Yeah, with mig, because the wire is hi ten, it is best to get it before it cools (hardens).
#23
_2DR_
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Posted 25 October 2009 - 11:26 PM
i would planish the weld while it was still hot so you have the best chance to manipulate the metal before it fully cools . there are a few different techniques .
space out your tacks 25 mm and hammer each one to keep the panels flush as possible then let cool.
then weld small sections between each of the tacks leaving sections out as not to generate to much heat in one section then let cool .
repeat untill fully welded and if you are going to cool the panel or weld i would use a air gun to blow cool air on it rather than wet rags you can also heatshrink using this method .
and remember be patient.
good luck
2dr
space out your tacks 25 mm and hammer each one to keep the panels flush as possible then let cool.
then weld small sections between each of the tacks leaving sections out as not to generate to much heat in one section then let cool .
repeat untill fully welded and if you are going to cool the panel or weld i would use a air gun to blow cool air on it rather than wet rags you can also heatshrink using this method .
and remember be patient.
good luck
2dr
#24
_Yella SLuR_
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Posted 26 October 2009 - 06:25 AM
Let it cool naturally, putting a dolly or hammer near a hot MIG weld will just induce a hot shrink and make everything worse. Cooling natural, while taking longer, all should come back to where you started.Cooling it slower and hammering the welds can help a little (not so easy with the mig but), hard to avoid it though
You can't really plenish MIG welds, just tends to bend the metal around the weld making everything very untidy.
I'm still very much on my L's as well, just picking up little tid bits the more and more I have a go.
Edited by Yella SLuR, 26 October 2009 - 06:28 AM.
#25
Posted 26 October 2009 - 08:21 AM
Yes let it cool naturally, you can hammer a little just before the weld is cool enough to touch (best not while red hot as you say have to wait for it to shrink first), but yeah its a short window of opportunity and mig doesn't really lend itself to this. If it can't be done without warping the panel around it then definitely just leave it
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