PerspexIt
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| posted on 3/4/03 at 07:23 AM |
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disappointing welding tests
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
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David Jenkins
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| posted on 3/4/03 at 09:38 AM |
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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
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PerspexIt
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| posted on 3/4/03 at 10:27 AM |
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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
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welshy
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| posted on 3/4/03 at 10:28 AM |
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Woudn't it be easier if everybody used an arc (stick)welding set?
It is so much easier/quicker to get nice results.
I am not Welsh!!!!!!!!!!
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James
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| posted on 3/4/03 at 11:32 AM |
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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.
You can get lovely results with arc if you're an expert- if you're not though it's blinkin hard! I've found arc far easier to
blow holes in the metal and then unless you've done it well you've then got to chip off the slag.
It even says in the book that 16gauge is a little thin for arc.
IMHO of course!
Cheers,
James
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leggin
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| posted on 3/4/03 at 11:51 AM |
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you idiot
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.
MIG IS FAR EASIER THAN ARC AND NEATER
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David Jenkins
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| posted on 3/4/03 at 12:03 PM |
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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]
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stephen_gusterson
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| posted on 3/4/03 at 01:54 PM |
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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
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David Jenkins
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| posted on 3/4/03 at 01:57 PM |
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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-)
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stephen_gusterson
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| posted on 3/4/03 at 02:05 PM |
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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-)
Well, idiot or not, you are a fast one!
I only posted that 2 mins ago.
Looks like we both have a rushed day down at 't mill.
atb
steve
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Mark Allanson
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| posted on 3/4/03 at 05:46 PM |
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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
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Viper
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| posted on 3/4/03 at 09:01 PM |
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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...
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Alan B
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| posted on 3/4/03 at 09:29 PM |
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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.
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Viper
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| posted on 3/4/03 at 09:40 PM |
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Just for the record i am a lloyds registered welder...
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Alan B
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| posted on 3/4/03 at 09:50 PM |
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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....
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Viper
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| posted on 3/4/03 at 09:54 PM |
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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....
Suns out huh?
lucky bugger
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Alan B
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| posted on 3/4/03 at 10:05 PM |
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It's not actually...miserable and overcast..:-(
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Viper
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| posted on 3/4/03 at 10:19 PM |
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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
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Alan B
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| posted on 3/4/03 at 11:12 PM |
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It's 6.12 now...5 hours ahead....make sure you come and say hello if you do come over....:-)
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Alan B
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| posted on 3/4/03 at 11:30 PM |
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erm....that's 5 hours behind...you are ahead..
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79 civic
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| posted on 3/4/03 at 11:33 PM |
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i have a very similar welder, i use max power and i use between 5 and 6 speed
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79 civic
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| posted on 3/4/03 at 11:33 PM |
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i have a very similar welder, i use max power and i use between 5 and 6 speed this has good results
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Mark Allanson
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| posted on 4/4/03 at 07:58 PM |
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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
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Viper
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| posted on 4/4/03 at 08:25 PM |
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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.
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Mark Allanson
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| posted on 4/4/03 at 08:41 PM |
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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
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