Hi,
i'm here at office, thinking about what went wrong with my welding tests yesterday evening.
As suggested in the books i have, i did some tests using a plate with good results, the bed was smooth, not to thin, not to thick.
Now it's some days i'm trying to weld two pieces of tube with very bad results.
Seems the welding bed attach well only to one tube, not to both.
The gap between the tubes is minimal (max 1mm) i spent a lot of time trimming the connection with a file.
So bad i dont have a digital camera for take pictures, i hope my poor english can explain the problem.
I'm using a DECA MIG 145A, argon+co2, 3/4 of the max power, about 1/2 of the max wire speed.
The only doubt i have it's about the wire, i still use the two boxes was included in the cost of the welder. This evening i'll try with a
new box.
Can be a problem of settings? Materials? Or just my fault?
Any help, in this dark, raining day.. is welcome!
-P
Practice, practice, practice... ;o)
Welding into a corner is one of the "medium" skills. You have to ensure that your torch is just about at an equal angle to both pieces
(i.e. 45 degrees from each piece for a 90 degree joint) with the wire going directly onto where the 2 pieces join. I would guess that this is your
major problem.
Some people like to weave very slightly from one side of the weld to the other, but this shouldn't really be necessary.
Gas flow shouldn't be a concern if your flat welds are good, as the shielding will be better into the corner.
Be sure to make life easier for yourself - ensure that the metal is clean and grease-free. Make sure that the wire isn't wobbling around in a
worn tip.
You should only need about the same volts and wire speed as for a flat weld between 2 pieces of steel plate - in fact I've sometimes found that
I've needed to reduce heat input a bit.
Are both pieces the same thickness? If one is thicker than the other then the skill level required rises a bit (you have to put more heat into the
thicker bit by increasing the angle of the torch, and/or weaving fractionally more towards the thick piece and less to the thin one).
Hope this helps!
David
Thank you very much for the help David! A bit of optimism is back now. This evening i'll continue with my tests.
Thanks again
-P
Woudn't it be easier if everybody used an arc (stick)welding set?
It is so much easier/quicker to get nice results.
quote:
Originally posted by welshy
Woudn't it be easier if everybody used an arc (stick)welding set?
It is so much easier/quicker to get nice results.
quote:
Originally posted by welshy
Woudn't it be easier if everybody used an arc (stick)welding set?
It is so much easier/quicker to get nice results.
Now, now, no need to be rude...
I've met a couple of welders who would cheerfully weld 1mm sheet with a stick welder - no blow holes, and the slag clicked off as it cooled,
leaving an immaculate weld.
Trouble is, it took each of them 30 years of practice to get that good!
MIG is best for amateurs like wot most of us are... ;o)
DJ
[Edited on 3/4/03 by David Jenkins]
my slight disagrement with David (who isnt an idiot :0) ) is :
I WOULD recommend, and I think its in several guides, that you SHOULD move the torch in a slight zig zag, or you may tend to get most of the heat in
one part of the steel only.
On my little 100A welder, im pretty sure that its virtually essential to do this.
atb
steve
quote:
Originally posted by stephen_gusterson
my slight disagrement with David (who isnt an idiot :0) ) is :
quote:
Originally posted by David Jenkins
quote:
Originally posted by stephen_gusterson
my slight disagrement with David (who isnt an idiot :0) ) is :
What do you mean by saying that I'm not an idiot! I'm very proud of my status, and have worked hard to achieve that ranking!
erm...
DJ
8-)
Are you welding downhand? If so the weld pool will run over the workpiece giving what looks like a good weld but will have virtually no penetration.
On tube, ALWAYS weld upwards or horizontally, never weave the torch unless you are putting down a second pass over a root weld. Another thing to
remember is to push the torch forward along the weld path, not drawing it back, and at about 80 degrees to the workpiece, but as been said earlier,
split the angle between any joints, but still 80 degrees to the weld path.
My home welder is a clarke 140, about 15 years old but still going strong, my wire speed is about a quarter up the scale when welding with 3/4 power,
if you have the wire too fast you may be compensating by welding too fast and again getting very little penetration. Although my welder is designed to
take 15kg wire spools, the flywheel effect of the larger spool gives a jerky effect to the wire feed and will only get really good results with 5kg
spools.
I hope this does not confuse the issue any further!?!
Mark
On Tube allways weld uphand?????????????????????????????? is it still April 1st??
This is 16swg we are talking here.....if you can't get full penetration downhand on 16swg wether its tube or rhs or whatever then you are doing
something seriously wrong...
Hmmm?....a little controversy here....
(was going to say "fight, fight fight"....but that would be childish!)
I'm with Viper on this in 25 years of welding I've never MIGed anything under 2mm thick upwards...always down...nor am awre of any weld
failures either.....
The debate continues....
No disrespect to Mark BTW who is obviously experienced too.
Just for the record i am a lloyds registered welder...
Looks like I sided with right guy....he he..(joking Mark)
For the record I used to have a Lloyds bank account....(true, but another joke)
Sorry guys I'm just very jovial today....
quote:
Originally posted by Alan B
Looks like I sided with right guy....he he..(joking Mark)
For the record I used to have a Lloyds bank account....(true, but another joke)
Sorry guys I'm just very jovial today....
It's not actually...miserable and overcast..:-(
the wife is bending my ear, she wants to know what time it is over there and is mumbling something about holidays..must keep her away from the vodka
It's 6.12 now...5 hours ahead....make sure you come and say hello if you do come over....:-)
erm....that's 5 hours behind...you are ahead..
i have a very similar welder, i use max power and i use between 5 and 6 speed
i have a very similar welder, i use max power and i use between 5 and 6 speed this has good results
On Tube allways weld uphand?????????????????????????????? is it still April 1st??
Just for the record i am a lloyds registered welder...
Viper,
I am also Lloyds certificated, I have ASME IV 6G MMA, BS4872 in arc, mig, and tig, and have been a part time lecturer at Cornwall College. I have
worked at Hinkley Point Nuclear Power Station as a construction welder and 10 years as a Welder fabricator, but now work in the Crash Repair
Industry.
You and I can weld uphand, down hand and even do little pictures of mickey mouse unsupported using MIG with the wire speed turned up, but the poor
chap who originally posted this thread cannot.
I thought if he is welding down hand, producing a weld pool which is being supported by over advanced wire speed, the weld pool would barely touch the
workpiece and would be 'balanced' on the end of the wire. It is just about the only way I could produce a good looking weld with zero
strength.
If he welds uphand, this would be impossible, and I suspect the wire speed is too fast for the amperage. It is a common fault, most wire feeds are
designed for an entire range of welders and if using 0.6mm wire with moderate amperage, the wire speed control would be in the lower 1/4 of the scale
if the welder is capable of using 0.8mm or even 1.2mm wire.
Have you any further ideas why an externally good looking weld would have no penetration?
No hard feelings
Mark
no hard feelings taken
(asme9 g5 mma)
the first thing that struck me was he said he was getting a good run on one tube only, so no matter how much penetration he is getting the tubes
won't stay together...obvious i know but if the run he is getting is good then is he using a magnet to hold the two tubes? perhaps that is
pulling his arc, this i would have thought he would see unless he is using a very dark lens (god bless modern headshields) it is difficult to diagnose
a problem when you can't see what is going on.
I had not thought about welders hands (magnets) causing the problem, I have never had much of a problem with arc blow with mig, but it can be a real
sod with DC MMA.
Without seeing any images, I think it's a toss up between wire feed and/or torch angle. Bad earth location (doubtful) could cause problems.
Perplexit, can you post any images so we can help you out?
Mark
between you two guys, you ought to be able to give us some definitive advice on welding - like write a short course and post it here - dispel some of
the myths and stress some of the good advice.
I have seen Viper's welding - we use it in most of the machines my company produces and its leak proof even when holding a vat of thin oil.
atb
steve
Hi All!
Thanks all your answers, i had some busy days at office, we have a demo the next week and the program need tests... like my welding.
Hopefully i'll be back home early so i can try again.. the next week i'll buy a digital camera.. so i'll post my horrible welds!
Have a good weekend!
-P
[Edited on 5/4/03 by PerspexIt]
Hi,
This is mainly a question for Mark due to his use of a Clarke welder similar to mine but anyone else feel free to answer too:
I wondered if you might be able to give me a bit of advice on power and wirefeed settings appropriate to welding 2mm thick SHS (25mm sq) (Note 2mm,
not 16swg)
It is a 120 Amp Clarke and I am currently using full power and between 6 and 7 on the wire feed. I always feel like I'm too rushed when welding
because the pool piles up too quickly but penetration seems to be variable. If I get a hot start (short stick out) then I can get good pen. but if I
use a half inch stick out as I think most people recommend then I just get an initially lumpy weld before it starts to penetrate.
I also quite often get little craters at the end of a weld sometimes where it seems like air is bubbling out and causes a void.
Final point is regarding the welding electrode and gas cup relationship. One other thread on this forum said that the gas cup should be positioned
such that the electrode stuck out by a few millimeters and this does seem to improve penetration but my electrodes keeping fouling up. What is
recommended here? Should it stick out or stay within the gas cup?
Thanks for some useful tips already, I hope you get a chance to answer the above too.
Cheers,
Craig.
I use the full 140 amps and a wire setting of just under 4 using .6mm wire. I have the contact tip exactly level with the shroud.
The 'piling up' at the begining of the weld sounds like wire feed too fast or the earth is a bit dodgy, check the clamp still has good
tension in the spring, and that the earth cable has a good connection to the welder, this is often overlooked. The hollow at the end if the weld
sounds like you are stopping the feed too soon, watch carefully at the end of the pass and watch the weld pool swell, basically pause for about 1/2
second at the end of the weld.
I have a pressure guage fitted after the regulator, the gas pressure on my set works best at 10psi closed which equates to 2psi when the gas is
flowing which I find ideal.
If you are using .8mm wire, get some 250 amp tips, these are much bigger and do not expand as much when they get hot, this causes snagging of the wire
and unpredictable welds. If you have the wire feed set right, the amount of wire sticking out of the contact tip should be about what you started
with, 10mm.
Hope this helps a bit, do not go by my settings as gospel as we have different machines, and even identical machines work differently due to
manufacturing tollerances.
Mark
[Edited on 6/4/03 by Mark Allanson]
Mark,
Thanks for that, I will try a few settings to see how I get on, I think my wire feed is indeed too fast. I think that I should be using less wirefeed
and taking more time instead to get a nice flow.
I should have said that I'm using CO2 just now for tack welding but hope to move to Argomix for seam welding. I know CO2 is usually said to give
better penetration but would you expect this to require different settings on the welder when I make the change?
One final clarification, when you say "you use the full 140 Amps" is this for 16 swg or were you meaning this is what you would use for
2mm?
Thanks again,
Craig.
Both, always use the maximum power you can handle without getting any undercut, or massive ditortion
Cheers m8, I'll give it a try tomorrow night.
Craig.
ps. Is 120A enough for 2mm tubing?
Try this file, I can't remember where it came from but it's a good read 
MIG Welding Document
Hi,
I found this document a little while back (Liam's guide to welding). I think it was on the other list in the files section. Thanks for reminding
me though because reading it again is useful.
Craig.
This seems to be the place to ask any welding questions.
I have a 150A welder and am only using it at about half power if that with a slow wire speed and slow movement just allowing the welding pool to move
slowly along and this seems to have ok penetration. If i turn the welder power up i just end up with big holes yet everyone else seems to have welder
set to as high as possible.
Is this wrong? or are you all just moving torch quicker?
[Edited on 10/4/03 by Gremlin]
Hi Gremlin,
I'm no expert but will reiterate something I read elsewhere.
Be aware that just because you have a nice weld pool running into the area between the metals to be joined might not equate to good penetration in
itself. This scares me a bit because a good looking weld might not be strong at all! Very worrying!
The advice I found was to practise on two bits of steel butted together and make sure that you actually see full penetration by looking from behind
and seeing a little bit of drop through and even "blue'ing" of the metal on either side.
HTH,
Craig.
ps. It's a bad sign when I give welding advice so hopefully one of the resident experts will elaborate and/or tell me to shut up 
Have done and seem to. Perhaps because im moving quite slowly to the weld pool has time to heat through material properly?
Thanks for advice i may go away and try slightly higher power.
I have tried braking appart a couple of pieces of material i have welded and the material tears around the weld where the material is weekend by the
heat but the weld has held no problems.
Any other thoughts?
[Edited on 10/4/03 by Gremlin]
Hi, i had time for do other tests in the last days, the result with square tubes it's much much much better.
Was a mix of mistakes, i changes the kind of wire, i rented a big bottle of gas instead the small disposable one.. and now is not the "cream of
the cream" but it's not so bad, and very important, it's STRONG. I can jump up and down on the welded parts without cracks.
Now.. any hints about weld round tubes? I tried, but i got other "disappointing welds"
Many tanks and best regards,
-P
I hate welding round tubes - never managed to get a pretty result.
It's the combination of keeping the correct angle, moving across the work, AND trying to go round a radius that messes me up.
I'm afraid the 'P' word is the answer again - practice!
cheers,
David
Hi,
What size wire are you using? I'm getting good results with .25 or .o25 what ever it is? Non flux coated. I've had to take a couple things
off and even tacked they were hard to remove. Even after I cut the tacks with the grinder.
I like the slight zig zag motion myself.