DTSFab.com (Desert, Trail and Sand)
The Machine Shop => Everything Fabrication => Topic started by: artie on edge on June 24, 2009, 07:07:05 PM
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I just wanted to share with the forum an epiphany I experienced last weekend.
I had been using a mig welder for decades, just like many here. I had NEVER ever had any training of any kind, read a bit, but mainly just practise.
Results? Well, the best thing I can say is that they are strong, if not a bit daggy in appearance. I trust them.
I had a good look over the chassis a few months ago (with a 'critical' eye) and thought that some of the welds COULD look better. Ive seen some of the struff on soem machines on here and other sites and the welds looked very attractive (no doubt they are structurally sound for the most part as well).
My car is due to front up to the Head Scrutineer some time later this year and be assessed for the issue of a CAMS logbook. They can only assess the welds by their appearance as they obviously werent around when the welding took place.
Therefore I wanted the welds to look better. With this in mind I contacted one of my old work colleagues (back when I was a TAFE teacher...prolly tradeschool to you guys) who is a welding teacher and asked him for a final touch up on those welds I wasnt happy with.
This occured last weekend. And I should have seen this coming....
Mate, Im not always gonna be available to do this for you...... Yeah, So what? I says....
Im NOT going to reweld your chassis. Im going to teach YOU how to do it.,.... Oh shxt! Ok...
So what I would like to do is share with those lesser gifted welders on the forum (like me!!) my lessons from the day and some results.
Before I begin, NOT all my welds needed redoing. The majority were quite ok. Just sayin...... 8)
Ok, first thing he did was make me just grab the machine and weld some scrap.... he watched then looked over everything.
From there he made me strip my helmet and clean it. Bloody hell! What a difference that made. I do do it, but hadnt for a while...slack... lesson one, do it regularly.
Second thing was I used his helmet and its so different. Its a very good unit, so you do get what you pay for. But the main thing was magnifying lenses. Nothing to do with poor eyesight just getting it all into clearer perspective. Very very nice to use. He had a set for me but my helmet didnt have the clips to mount them (they go inside). Out came the race tape. Fantastic and only a few bucks at your welding supply joint.
He then made me strip my handpiece, remove the lead from the machine and cleaned out the liner (compressed air). Mine was liberally coated inside with copper dust from the wire coating. New tip, shield and shield mount (mine was a bit loose and the shield was sliding back). Refitted to machine.
Reduce the copper dust by adjusting the feed roller correctly. The tension setting should be tight, but not so tight that you cant stop the wire roll from turning with one finger. Any tighter and the roller crushes the copper coating on the wire and eventually causes problems with copper contamination inside the liner.
Ramification number two. I had had a problem whereby occasionally the tip would 'stick'...arc would burn up to the tip and the wire would lightly 'stick' to the nozzle. Just a twist with the handpiece and away you go again EXCEPT my rollers would continue to feed wire and it would be a tangled mess on the feed into the liner. This no longer happens as the feed roller now slips on the wire rather than force feeding it.
Tip dip.... Use it. It makes a hell of a difference to the crap that sticks to your shield. Apparenty for a while there was a rumour that this stuff produced a carincogenic gas when burnt. Not so, just an old wives tale.
Gas pressure, yeah..uhm.. no idea what it should be ..just enough..?? Cleaned my gauge glass (oops bad huh?) and set it to about 12 to 15 psi. So why isnt the 25 like I had it set at better? The gas comes out too fast and acts like a venturi as it leaves the tip and draws air into the weld pool causing oxidisation while welding.... ahhh... that made sense..... Also...SHUT THE BLOODY WORKSHOP DOOR! Tried it open (sort of a windy day) yeah it made a difference allright, stop the major drafts folks....keeps the gas shielding the weld pool like it is supposed to....
My technique with the handpiece was ok (apparently) and the difference was amazing upon my second attempt.
We discussed the benefits/disadvantages of drawing the hand piece or pushing the hand piece. He was happy for either to happen, whatever I was comfortable with, BUT you tended to get deeper penetration with a drawing hold. I am a natural 'drawer' that is the hand piece is pointing back towards the weld as I move my hand. In his opinion there was no 'correct' style, whatever worked best for the application and the individual. The text book says that pushing or square to the weld plane is the 'correct' style. Whatever.
We then experimented on various sized pieces of steel to find the correct 'tune' for the wire speeds and voltages. No big revelations here except that local current draw on the grid around you can make a difference. At around 12:30 (saturday) the machine required retuning. His opinion was that people are arriving home from work and the grid load just increased... food for thought....
Final thing. Dont try and weld right around the tube in one go if it isnt comfotable to do so. Do it in segments and concentrate on a smooth deep bead....
OK Grind like hell and then do some welding..... results....
What I was producing (this is an ok one)
(https://dtsfab.com/proxy.php?request=http%3A%2F%2Fi293.photobucket.com%2Falbums%2Fmm54%2Fartieonedge%2FWeldOrig.jpg&hash=606bc663c3b8798a85f9055c2694f1c3d2c3fdea)
(https://dtsfab.com/proxy.php?request=http%3A%2F%2Fi293.photobucket.com%2Falbums%2Fmm54%2Fartieonedge%2FWeld1.jpg&hash=dbd754df5ef7d79645f523d68e1e37539761f11b)
(https://dtsfab.com/proxy.php?request=http%3A%2F%2Fi293.photobucket.com%2Falbums%2Fmm54%2Fartieonedge%2FWeld2.jpg&hash=ffacda67693d30e29882cb51436c4fa048461752)
(https://dtsfab.com/proxy.php?request=http%3A%2F%2Fi293.photobucket.com%2Falbums%2Fmm54%2Fartieonedge%2FWeld3.jpg&hash=5c3949fcd5aa682336d840b50ddba68d64d82b56)
(https://dtsfab.com/proxy.php?request=http%3A%2F%2Fi293.photobucket.com%2Falbums%2Fmm54%2Fartieonedge%2FWeld4.jpg&hash=850758db5577904117653317c5dd8886ede71491)
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You're running straight CO2 aren't you?
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You're running straight CO2 aren't you?
Nope. argon and co2.
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Isnt there a splatter issue with Co2? We discussed the various gases available on the day. Advice was to stay with this mixture. I think he meant until/unless I was a better welder.... oops better stock up on this stuff then.... ;D
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what you got will be just fine.
Yes CO2 will splatter a lot.
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There's a heap of good stuff there Artie, well done mate! Made me think about a few things..
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;D
welder maintenance sure does make a world of difference
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Even just cleaning ya helmet makes a heap of difference.
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Ya,
I'm a stickler about keepin my helmet, nozzles and tips clean ;D
Yes that statement was BAIT :s
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Ya,
I'm a stickler about keepin my helmet, nozzles and tips clean ;D
Yes that statement was BAIT :s
Just like in golf huh? Keep your balls clean.... yeah Im a stickler for personal hygiene.
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ff:
Ya Keeping a clean nozzle and tips really do help,
I would like to add that there are some good liner conditioners out there...Liner upkeep is also really important to getting "good welds"
Something you touched on that will also be helpful to know is about roll tension, Roll tension is your friend...But too much you get what I call "auto weave"..that is where the wire weaves around when it leaves the gun...Not enouph tension will leave you without wire...a good way to guage your wire tension is to hold the gun at about 50* to the work surface with out the ground on...The wire should just barey slip and bend...if it stops your too loose if it goes or kinks in the lead the rolls are too tight 8)
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Yeah,well, keeping your lens clean so you can see your balls should help also.
Just like in golf huh? Keep your balls clean.... yeah Im a stickler for personal hygiene.
Yeah,well, keeping your lens clean so you can actually see your balls should help also. ;D ;D
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ff:
Ya Keeping a clean nozzle and tips really do help,
I would like to add that there are some good liner conditioners out there...Liner upkeep is also really important to getting "good welds"
Something you touched on that will also be helpful to know is about roll tension, Roll tension is your friend...But too much you get what I call "auto weave"..that is where the wire weaves around when it leaves the gun...Not enouph tension will leave you without wire...a good way to guage your wire tension is to hold the gun at about 50* to the work surface with out the ground on...The wire should just barey slip and bend...if it stops your too loose if it goes or kinks in the lead the rolls are too tight 8)
I've never migged a thing.Good to see some good advice from you guys.
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What do you Tig everything Master?
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I found keeping the stinger (welding ground clamp) as close a possible to where you are welding helps greatly. I assume its less resistance if keep close to where you work.
Chris
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hi
My technique with the handpiece was ok (apparently) and the difference was amazing upon my second attempt.
We discussed the benefits/disadvantages of drawing the hand piece or pushing the hand piece. He was happy for either to happen, whatever I was comfortable with, BUT you tended to get deeper penetration with a drawing hold. I am a natural 'drawer' that is the hand piece is pointing back towards the weld as I move my hand. In his opinion there was no 'correct' style, whatever worked best for the application and the individual. The text book says that pushing or square to the weld plane is the 'correct' style. Whatever.
the correct way is to point the tip in the direction you are going
back hand or dragging should be use when using fluxcore
backhand when mig welding will cause a lack of fusion on the toe of the weld
cheers
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Gas pressure, yeah..uhm.. no idea what it should be ..just enough..?? Cleaned my gauge glass (oops bad huh?) and set it to about 12 to 15 psi.
hi
the gauge is not showing psi it is showing volume l/min
cheers
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What do you Tig everything Master?
TIG and stick.
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hi
the gauge is not showing psi it is showing volume l/min
cheers
CFH, Cubic Feet per Hour for us Normal fellas... ;D
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I just purchased a new mig. I had one that I used to build gates for my fence company. I welded .055 wall galvanized tubing for 10 years. I used staight CO2. I tried argon CO2 mix once, I burned up tubing. I have been playing with new mig. I have been getting those lousy rope looking welds. I tried changing heat and wire speed. I ran out of the wire that came with the welder, it was .023. I had sold my fence company 2 years ago and hadn't used a mig since then. I remembered I always used .030 wire and ran pretty high heat when I built all those gates. I bought some .030 and cranked up the heat. Some of the welds look as good as my tig welds. Tim
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There seems to be the conception that people think that MIG welding is easy to do. In a way it is. But for the people that use it day in day out there the ones you should ask if its easier. I actually think that stick welding is the easiest of them all. To lay down a sweet MIG(especially doing heavy plate) its a fine art.
I work with all types of welders. MIG/TIG/Stick/Flux Cored. Your standard industrial welders. I can get one setup in a flash and running so sweet you couldn't hear it welding the most you hear is the Gas.
I'll share the things i've learnt over the years. Forgive me that its been repeated
1) Clean liners and correct tensions (Spec has the right idea)
2) Have tip cleaners on you. When the wire balls up on the tip you should clean it and it'll stop the wire from stopping half way through a weld
3) Keep the gas shield collet clean. This will keep the gas flow even and stop restricting it causing porosity. Tip dip is ok but i can't be bothered with it. If you set your machine up well you shouldn't get spatter.
4) Gas flow should be set 12-16Lmin in an enclosed area. Any more your just wasting gas.
5) Once your setup here you should know some basics with what welder your using. You will get different results from different welders. The amp range will help determine what to set your machine up for. Here is a basic rule i follow
Welding 3mm plate running .9mm wire single phase welders
160-180 amp machines - 7/8 of the amperage/wire feed will be needed to produce cleans welds
190-220 just under 3/4
220 - 250 1/2
250 - 320 just over 1/4
Thats for good penetrating welds
6mm plate double it.
6) I found that depending on what you feel comfortable with that pushing (as opposed to dragging with stick) produces clean welds. But not as deep penetration as dragging. You get a real nice bacon crackling sound when pushing(higher amps and you don't hear anything at all) But this is more than enough for buggy building. I had to repair a rock breaker arm the other day. Welds didn't even hold it. Clean broke off. They were MIG and pushed(i knew who did the welds) Mine were dragged and they bent the arm the next day(bloody wankers operators break everything)
7) When welding above head adjust the wire feed to suit. Your fighting gravity so a little more wire feed helps.
8 ) Keep you handle at about 45* each direction. Similar to stick.
9) Have about 12mm of stick out. This stops the chance of the wire balling up on the contact tip.
10)I found that before laying a run down that giving the wire a quick burn(arcing the wire so it gets some heat in it) helps stop the weld from raising at the start of a weld. You might need to clean the excess wire off but with practice you shouldn't get any.
11)Finally practice, practice, practice and practice some more. It takes time but you won't regret it.
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There's some good stuff in there Matt thanks for sharing Mate!! ;)
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weldingtipsandtricks.com!!!! great site for stick mig and tig,
one tip i took to heart was to buy a cheap autodarkening welding helmet.
good info matt.
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excellent website. I spent half the night there reading!. Great info
Chris